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An Outbreak of Escherichia coli O157:H7 Infections Associated with Leaf Lettuce Consumption
Abstract
In July 1995, 40 Montana residents were identified with laboratory-confirmed Escherichia coli O157:H7 infection; 52 residents had bloody diarrhea without laboratory confirmation. The median age of those with laboratory-confirmed
cases was 42 years (range, 4–86); 58% were female. Thirteen patients were hospitalized, and 1 developed hemolytic-uremic syndrome.
A case-control study showed that 19 (70%) of 27 patients but only 8 (17%) of 46 controls reported eating purchased (not home-grown)
leaf lettuce before illness (matched odds ratio, 25.3; 95% confidence interval, 3.9–1065.6). Pulsed-field gel electrophoresis
identified a common strain among 22 of 23 isolates tested. Implicated lettuce was traced to two sources: a local Montana farm
and six farms in Washington State that shipped under the same label. This outbreak highlights the increasing importance of
fresh produce as a vehicle in foodborne illness. Sanitary growing and handling procedures are necessary to prevent these infections.
... *Source: [146]. irrigation waters has been elucidated [50,116], and secondary vehicles by which E. coli O157:H7 may contaminate the leafy greens were identified: flood irrigation with water contaminated either with animal feces or by contact with surface runoff [117,118]. Experimental and on-field studies indicated the ability of the pathogen to survive for extended periods in water [119,120]. Many different sources of water and methods are used for irrigation of fresh produce [121]. ...
... Finding the sources of bacterial contamination in produce whenever an outbreak occurs can be complex due to several factors, including the short shelf life of the produce, the need for patients to recall their food consumption history, and tracing back the origin of the bacteria strain recovered from the patient back to its source (e.g., water), therefore, addressing produce contamination remains challenging. Nonetheless, agricultural water has been identified as a source of contamination in numerous outbreaks and from a variety of produce, including tomatoes, cucumbers, and leafy greens (Ackers et al., 1998;Greene et al., 2008;Laughlin et al., 2019;CDC, 2019a,b). Water has been associated with two of the most recent significant outbreaks in the United States linked to fresh produce. ...
Fresh produce can be contaminated by enteric pathogens throughout crop production, including through contact with contaminated agricultural water. The most common outbreaks and recalls in fresh produce are due to contamination by Salmonella enterica and Shiga toxin-producing E. coli (STEC). Thus, the objectives of this study were to investigate the prevalence of markers for STEC (wzy, hly, fliC, eaeA, rfbE, stx-I, stx-II) and Salmonella (invA) in surface water sources (n = 8) from produce farms in Southwest Georgia and to determine correlations among the prevalence of virulence markers for STEC, water nutrient profile, and environmental factors. Water samples (500 mL) from eight irrigation ponds were collected from February to December 2021 (n = 88). Polymerase chain reaction (PCR) was used to screen for Salmonella and STEC genes, and Salmonella samples were confirmed by culture-based methods. Positive samples for Salmonella were further serotyped. Particularly, Salmonella was detected in 6/88 (6.81%) water samples from all ponds, and the following 4 serotypes were detected: Saintpaul 3/6 (50%), Montevideo 1/6 (16.66%), Mississippi 1/6 (16.66%), and Bareilly 1/6 (16.66%). Salmonella isolates were only found in the summer months (May-Aug.). The most prevalent STEC genes were hly 77/88 (87.50%) and stx-I 75/88 (85.22%), followed by fliC 54/88 (61.63%), stx-II 41/88 (46.59%), rfbE 31/88 (35.22%), and eaeA 28/88 (31.81%). The wzy gene was not detected in any of the samples. Based on a logistic regression analysis, the odds of codetection for STEC virulence markers (stx-I, stx-II, and eaeA) were negatively correlated with calcium and relative humidity (p < 0.05). A conditional forest analysis was performed to assess predictive performance (AUC = 0.921), and the top predictors included humidity, nitrate, calcium, and solar radiation. Overall, information from this research adds to a growing body of knowledge regarding the risk that surface water sources pose to produce grown in subtropical environmental conditions and emphasizes the importance of understanding the use of abiotic factors as a holistic approach to understanding the microbial quality of water.
... The prevalence of pathogenic microorganisms in the soil is also dependent on its inherent characteristics such as temperature, pH, porosity, particle size, and water retention capacity (van Veen, van Overbeek, and van Elsas 1997;Ackers et al. 1998;Atkinson, Fitzgerald, and Hipps 2010). For example, Lang and Smith (2007) reported that E. coli may survive in both sandy loam and silty clay soil for around 31 wk; greater survivability for E. coli was observed in sandy loam soil compared to silty clay soil. ...
The number of food safety issues linked to wheat milled products have increased in the past decade. These incidents were mainly caused by the contamination of wheat-based products by enteric pathogens. This manuscript is the first of a two-part review on the status of the food safety of wheat-based products. This manuscript focused on reviewing the available information on the potential pre-harvest and post-harvest sources of microbial contamination, and potential foodborne pathogens present in wheat-based products. Potential pre-harvest sources of microbial contamination in wheat included animal activity, water, soil, and manure. Improper grain storage practices, pest activity, and improperly cleaned and sanitized equipment are potential sources of post-harvest microbial contamination for wheat-based foods. Raw wheat flour products and flour-based products are potentially contaminated with enteric pathogens such as Shiga toxin-producing E. coli (STECs), and Salmonella at low concentrations. Wheat grains and their derived products (i.e., flours) are potential vehicles for foodborne illness in humans due to the presence of enteric pathogens. A more holistic approach is needed for assuring the food safety of wheat-based products in the farm-to-table continuum. Future developments in the wheat supply chain should also be aimed at addressing this emerging food safety threat.
... Raw vegetables were the medium of alone bacterial strain in both happening.E. coli O157:H7 was a reportable agent in 1995, which led to foodborne infections within Maine and Montana. These two outbreaks from two regions were researched, and contaminated lettuce was declared as a source [27], [28]. Similarly, the outbreak of salmonellosis in 1990 in the Midwest was a justification for raw tomatoes (sliced) intake [29]. ...
Vegetable spoilage produces various microbes of different origins like parasites, fungi, viruses, and bacteria. This causes infections and diseases in vegetables, and later on, when humans eat these vegetables; diseases induce in humans. So, to prevent human diseases, the symptoms of various infections in vegetables must be known. Moreover, the conditions supporting the infections in vegetables must be understood. So that spoiled vegetable consumption can be prevented. Sometimes spoiled vegetables are regarded as disease free and suitable for consumption. These misconceptions sometimes lead to lethal human diseases, which in history led to major outbreaks. The antimicrobial resistance is faced by microbes which deteriorate the situation and make the cure of diseases.
... Thus, their consumption constitutes a potential risk factor for infection by enteropathogenic bacteria such as Salmonella and Escherichia coli 0157 [7]. Cases of food poisoning linked to the ingestion of contaminated vegetables have been identified all over the world [4,7,8,9]. Indeed, plant contamination can occur at any point in the food chain, from farms to consumer plates, via transport, distribution and markets, with the presence or absence of pathogens [6,10]. In recent years, the quality of foodstuffs on the market has tended to be disregarded by consumers in underdeveloped countries [11,12,13]. ...
Vegetables are an important food source of nutrients, vitamins and dietary fiber, and therefore play a vital role in human health and well-being. Unfortunately, they are perishable products that could be vectors for the transmission of infectious diseases. The aim of this study was to analyses the level of bacteriological contamination of the samples of tomatoes (29), carrots (12), lettuces (47) and onions (12) sold in five (5) markets of community urban of Niamey. To this end, contamination indicator germs such as Total Aerobic Mesophilic Flora (TAMF), Total Coliforms (TC), Faecal Coliforms (FC), Enterobacteria (Ent), Faecal Streptococci (FS), Clostridium perfringens (CP) and Escherichia coli (E. coli) were enumerated, using methods specific to each germ. Analysis of the results showed tomatoes to be highly contaminated with FS, CP and E. coli (9.75±1.81.105; 1.33±2.30.105 and 2.25±2.48.105 CFU/g respectively), carrots with TAMF, FC, Ent (1.37±1.24.107; 4.48±0.34.106; 7.44±0.34.106 CFU/g respectively) and onions with TC (4.45±0.84.106 CFU/g). The sanitary quality of these vegetables is low. Hence the need for strict compliance with good hygiene practices in markets to ensure a healthy vegetable.
... In feedlot settings, approximately 30% of cattle excrete E. coli O157:H7, as reported by Callaway et al. (2009). Several previous studies have revealed that the outbreaks related to E. coli O157:H7 originate from many different sources including salad sprouts (Fukushima et al., 1999) and green lettuce (Ackers et al., 1998). Another noteworthy example is an outbreak that occurred in Germany in 2011 where over 4,000 cases of severe gastroenteritis with more than 850 cases of HUS, together with 49 fatalities, were caused by the STEC infection epidemic (EFSA, 2011). ...
Escherichia coli is a foodborne pathogen that causes severe illnesses in humans worldwide. Cows are a source of E. coli O157:H7, and raw products contaminated with cattle faeces are typical carriers of the pathogen. The consumption of unhygienic fresh fruits and vegetables provides a potential risk factor for microbial contamination-related infections. In this context, the present work was performed to investigate the prevalence rate of E. coli in fresh fruits and vegetables that were commonly distributed and consumed in Zakho City, Iraq. In addition, the present work also aimed to detect the incidence rate of pathogenic strain E. coli O157:H7, thereafter suggesting the best and most efficient sanitiser for the decontamination of fruits and vegetables. A total of 172 samples, comprising various types of fruits and vegetables, were randomly collected for this cross-sectional study from retail markets in Zakho City. A number of laboratory tests, including DuPont BAX System PCR, microbiological, and biochemical-based techniques were performed for the isolation and identification of E. coli microbial contamination. Out of the 172 samples collected, 32 (18.6%) tested positive for E. coli using traditional enrichment and selective media. The DuPont BAX system technique confirmed that all isolates were E. coli, and none of the isolates were identified as E. coli O157:H7 strain. Furthermore, peracetic acid was found to be a more effective sanitiser than aqueous chlorine for cleaning leafy green vegetables. Despite the absence of the pathogenic strain E. coli O157:H7, the present work highlighted the potential health risk to the community due to E. coli contamination of leafy green vegetables.
... Similarly, antimicrobial agents used for crop diseases may contribute to increase pressure on microbes to became resistant or crop could be contaminated from manure used as fertilizer (Figure 3). In the USA, fresh green leafy vegetables have been associated with several outbreaks of enteric pathogens [195,[197][198][199][200]. Similarly, fresh vegetables may carry AMR bacteria such as ESBLs-Ent that can enter the human gut when consumed uncooked [201][202][203]. ...
Antimicrobial resistance (AMR) is one of the top global health threats of the 21th century. Recent studies are increasingly reporting the rise in extended-spectrum beta-lactamases producing Enterobacteriaceae (ESBLs-Ent) in dairy cattle and humans in the USA. The causes of the increased prevalence of ESBLs-Ent infections in humans and commensal ESBLs-Ent in dairy cattle farms are mostly unknown. However, the extensive use of beta-lactam antibiotics, especially third-generation cephalosporins (3GCs) in dairy farms and human health, can be implicated as a major driver for the rise in ESBLs-Ent. The rise in ESBLs-Ent, particularly ESBLs-Escherichia coli and ESBLs-Klebsiella species in the USA dairy cattle is not only an animal health issue but also a serious public health concern. The ESBLs-E. coli and -Klebsiella spp. can be transmitted to humans through direct contact with carrier animals or indirectly through the food chain or via the environment. The USA Centers for Disease Control and Prevention reports also showed continuous increase in community-associated human infections caused by ESBLs-Ent. Some studies attributed the elevated prevalence of ESBLs-Ent infections in humans to the frequent use of 3GCs in dairy farms. However, the status of ESBLs-Ent in dairy cattle and their contribution to human infections caused by ESBLs-producing enteric bacteria in the USA is the subject of further study. The aims of this review are to give in-depth insights into the status of ESBL-Ent in the USA dairy farms and its implication for public health and to highlight some critical research gaps that need to be addressed.
... Pathogens may be relocated to the ecosystem by the remedy of inefficiently composted or raw cattle composts or sewage 35-38 . The feces of wild animals may similarly be a resource 39,40 . In laboratory circumstances, infected flies have been revealed to the straight transmission of bacteria to plant leaves or fruits [41][42][43] . ...
Raw salad vegetables are considerable ingredients of vital nourishment but have been associated with relevant days with a
flourishing threat of food poisoning from bacterial pathogens for substantial known health trouble, extremely little is recognized regarding the behavior performance of Salmonella sp. with
raw salad vegetables. The contemporary effort estimates the microbiological
Surat city, Gujarat, India. A sum of 300 samples of 5 discrete largely consumed raw salad vegetables (Tomato N=60,
Cucumber N=60, Cabbage N=60, Spinach N=60, Carrot N=60) from local vegetable markets were endophytic Salmonella sp.in relations of aerobic counts after removing surface microflora. Salmonella sp. has been detected 11.3 % of the total samples. Most Salmonella sp. isolated from above raw salad vegetables observed to have resistance. The investigation statistics reveal that raw salad vegetables may promote the durability of Salmonella sp. within
raw salad vegetables. Endophytic Salmonella cells from salad vegetables could not be removed by simple washing and
intensely highlight the significance of confirming the microbiological safety of raw salad vegetables.
Keywords: Salmonella typhi fitness, Plant contamination, Multidrug resistance, Immune response, Food safety.
... In several USA states, in the period of August-September 2006, illnesses due to outbreaks of Escherichia coli O157:H7 associated with the consumption of packed spinach have been documented (Wendel et al. 2009). Earlier, in the summer of 1995, in Montana state, E. coli associated with the consumption of contaminated lettuce leaves had led to the outbreak of infections of people mainly at age around 40 (Ackers et al. 1998). A representative of the risks for human health imposed by E. coli O104:H4 are also the cases in Europe in the year 2011 when nearly 4000 persons have been infected, 900 of which expressed hemolytic-uremic syndrome, and 54 died (Karch et al. 2012). ...
Adaptation of plant and human pathogenic bacteria to niches of existence differing from their original ones is a sophisticated mechanism for survival. Research indicates that certain plant bacterial pathogens are capable of causing disease in humans, and some human bacterial pathogens can inhabit the plant environment and cause disease in plants. The infection of humans by plant bacteria may occur at direct physical contact with diseased plants and/or via the respiratory tract in mainly immunocompromised or otherwise stressed individuals. Indirect transmitters of plant and human microbes can be wind, rain, dust, insects, and animals. Human pathogenic bacteria may contaminate the soil and irrigation water, colonize the rhizosphere, more rarely also the phyllosphere, and can survive as epiphytes. Thus, the plant environment may become a reservoir of human pathogens. A source of foodborne human pathogenic bacteria can be unprocessed or unwashed fruits and vegetables. Especially during the last decade, the processes underlying the cross-kingdom performance of pathogenic bacteria are intensively researched. However, in reality, the risk for human health at infections by plant bacteria and by human bacterial pathogens surviving in the plant environment is still underestimated. The goal of the current review is to increase the interest in these issues in agricultural and general environments. Some basic strategies for infection and symptoms of diseases caused by the microorganisms under consideration are described. The potency of certain plant bacterial pathogens to surpass barriers towards humans and the interaction of human bacterial pathogens with the plant environment are addressed and the existing information is critically discussed.
... Many of its strains are harmless but some of them are not. They can enter the body mainly through the consumption of polluted food or water that was contaminated with them, but it can also be ingested with the consumption of raw vegetables irrigated with polluted water (WHO 2018, Ackers 1998, Tarr 2001). ...
... Various foods contain such strains: ground beef, fresh milk, apple cider [49][50][51][52][53][54][55], or fermented hard salami [56]. Although the most dangerous EHEC, E. coli O157:H7, has been associated with foods of bovine origin in Michigan and Oregon, USA, in 1982 [57], it was also found in goat's milk, lettuce, and alfalfa sprouts [58][59][60][61]. Investigating the presence of STEC in 4330 Korean food samples, Ryu et al. [62] determined the highest prevalence of the bacterium in yukhoe (forged raw meat), cold bean soup, gimbal (meat broth for cold noodles), and sprouts, as well as that 17.7% of the obtained E. coli strains, were resistant to antibiotics. ...
Toxic ingredients in food can lead to serious food-related diseases. Such compounds are bacterial toxins (Shiga-toxin, listeriolysin, Botulinum toxin), mycotoxins (aflatoxin, ochratoxin, zearalenone, fumonisin), pesticides of different classes (organochlorine, organophosphate, synthetic pyrethroids), heavy metals, and natural antinutrients such as phytates, oxalates, and cyanide-generating glycosides. The generally regarded safe (GRAS) status and long history of lactic acid bacteria (LAB) as essential ingredients of fermented foods and probiotics make them a major biological tool against a great variety of food-related toxins. This state-of-the-art review aims to summarize and discuss the data revealing the involvement of LAB in the detoxification of foods from hazardous agents of microbial and chemical nature. It is focused on the specific properties that allow LAB to counteract toxins and destroy them, as well as on the mechanisms of microbial antagonism toward toxigenic producers. Toxins of microbial origin are either adsorbed or degraded, toxic chemicals are hydrolyzed and then used as a carbon source, while heavy metals are bound and accumulated. Based on these comprehensive data, the prospects for developing new combinations of probiotic starters for food detoxification are considered.
... For example, crisping was suspected as a cross-contamination point in an Escherichia coli (E. coli) O157:H7 outbreak that occurred in Montana (USA) in 1995 (Ackers et al., 1998). Brochures and training materials from industry and commodity groups, such as 'Crisping fresh produce procedures' (IGA Institute, 2005), 'The Network for a Healthy California-Retail program: Retail fruit and vegetable marketing guide' (California Department of Public Health, 2011), 'DeCA manual 40-4.1: ...
The efficacy of commercially available antimicrobials for fresh produce, electrolyzed water (EW; ca. 60 mg/L of free chlorine), a combination of lactic acid and phosphoric acid-based (LPA), and citric acid-based (CA) was compared with tap water (TW) in preventing cross-contamination during the soaking step of crisping at a retail setting. A bunch of cilantro (103.7 ± 14.9 g/bunch) was inoculated with 3-strain cocktail of nalidixic acid-resistant Salmonella enterica and E. coli O157:H7, S. enterica and Listeria monocytogenes, or E. coli O157:H7 and L. monocytogenes (ca. 5.0 log CFU/g). One inoculated and seven non-inoculated cilantro bunches were soaked in 76 L of TW, EW, LPA, and CA for five minutes. Two additional soakings, each with eight bunches of non-inoculated cilantro were performed in the same soaking water. To determine the cross-contamination of inoculated foodborne pathogens via soaking water, the cilantro samples and soaking water following each soaking step were subjected to microbiological analyses using selective media supplemented with nalidixic acid (100 μg/mL). During the first soaking, significantly greater reductions in Salmonella (2.9 ± 0.5 log CFU/g), E. coli O157:H7 (3.0 ± 0.1), and L. monocytogenes (2.7 ± 0.3) on cilantro were achieved with EW compared to soaking with TW, LPA, and CA (P < 0.05). Cross-contamination of foodborne pathogens from inoculated cilantro to non-inoculated cilantro was completely mitigated by EW during three subsequent soaking events. With the exception of TW soaking water, no inoculated foodborne pathogens were detected in the 100 mL soaking water of EW, CA, and LPA collected. Including an appropriate concentration of chemical antimicrobial in water during the soaking step of crisping aids in mitigating cross-contamination of foodborne pathogen(s) in cilantro bunches.
... Fecal contamination of surface water represents a public health hazard, and threatens the economic and recreational value of waterbodies (Rabinovici et al., 2004;Dwight et al., 2005;Given et al., 2006;DeFlorio-Barker et al., 2017;U.S. Environmental Protection Agency SIM., 2018;Calderón-Arrieta et al., 2019). Indeed, fecal contamination of agricultural or recreational water has been identified as the probable cause of multiple enteric disease outbreaks (Ackers et al., 1998;Wachtel et al., 2002;Johnson, 2006;Greene et al., 2008;Barton Behravesh et al., 2011;Food Drug Administration, 2019. For example, a 2008 multistate Salmonella outbreak in the United States was traced back to the use of contaminated water to irrigate hot peppers in 2008. ...
Fecal contamination of surface water has been associated with multiple enteric disease outbreaks and food recalls. Thus, it is important to understand factors associated with fecal contamination of agricultural water sources. Since fecal indicator bacteria (FIB) were used to monitor surface water for potential fecal contamination, the purpose of the present study was to characterize associations between environmental factors, and (i) FIB ( E. coli, Enterococcus , and coliform) levels, and (ii) host-specific fecal marker detection. This study used data collected from 224 sites along 3 waterways, which spanned an urban-rural gradient around Syracuse, New York. Between 2008 and 2017, 2,816 water samples were collected, and E. coli, Enterococcus , and/or coliform concentrations were enumerated. Thirty-one samples were also tested for human and ruminant microbial source-tracking markers. Water quality (e.g., turbidity, nitrate) and weather data were also collected for each site. Univariable Bayesian regression was used to characterize the relationship between each microbial target and land use, water quality, and weather factor. For each model, probability of direction and region of practical equivalence overlap (ROPE) were calculated to characterize the association's direction and strength, respectively. While levels of different FIB were not correlated with each other, FIB levels were associated with environmental conditions. Specifically, FIB levels were also positively associated with temperature, nutrient and sediment levels. Log10 E. coli levels increased by 0.20 (CI = 0.11, 0.31) and log10 Enterococcus levels increased by 0.68 (CI = 0.08, 1.24) for each log10 increase in salinity and nitrate, respectively. These findings may indicate that similar processes drove microbial, sediment, and nutrient contamination of the sampled watersheds. While fecal contamination was strongly associated with land use, the direction of association varied between FIBs and the buffer distance used to calculate land use metrics. E. coli levels and human marker detection were positively associated with percent pasture cover within 122, 366, and 1,098 m of the sampling site, while Enterococcus and coliform levels were only associated with pasture cover within 1,098 m (not 122 or 366 m). Ruminant markers were positively associated with pasture cover within 122 m, but not 366 or 1,098 m. These findings highlight the importance of considering (i) adjacent land use (and associated non-point sources of contamination) when developing strategies for managing fecal hazards associated in agricultural and recreational water, and (ii) spatial scale (e.g., 122 vs. 1,098 m) when developing these strategies.
... *Source: [146]. irrigation waters has been elucidated [50,116], and secondary vehicles by which E. coli O157:H7 may contaminate the leafy greens were identified: flood irrigation with water contaminated either with animal feces or by contact with surface runoff [117,118]. Experimental and on-field studies indicated the ability of the pathogen to survive for extended periods in water [119,120]. Many different sources of water and methods are used for irrigation of fresh produce [121]. ...
Consumption of fresh leafy greens has been repeatedly reported and linked to pathogenic Escherichia coli-associated foodborne illnesses outbreaks. Leafy greens are mostly eaten raw, based on the increased consumers' preferences for natural, nutritious diets. Recent studies indicate the incidence of infections caused by patho-genic Escherichia coli remained almost unchanged or even increased. In this context, fresh produces increased the awareness about their primary contamination level, namely the pre-harvest phase. Fully eliminating pathogenic Escherichia coli from pre-harvest environment proved to be impossible. Emphasis must be placed on the pre-harvest factors that affect the food safety and, subsequently, on the identification of possible mitigation strategies that can be used on-farm for reducing the risk of leafy greens contamination with pathogenic Escherichia coli.
... can reduce water quality as well. Livestock can contaminate stream water through direct contact or from runoff contaminated with feces and urine (Line et al. 2000, Davies-Colley et al. 2004, and subsequent use of contaminated water has been linked to disease outbreaks in humans (Ackers et al. 1998, Jay et al. 2007, Lindqvist et al. 2008. Other water quality indicators such as sediment particles, suspended solids, nutrients, and dissolved oxygen can be influenced by livestock presence in watersheds (Line et al. 2000, Line 2003, Ranganath et al. 2009). ...
Wild pigs (Sus scrofa) are a highly invasive species in the United States and millions of dollars are spent annually on removal efforts and damage reduction. Wild pigs may act as ecosystem engineers in areas where they are established, so it is important to fully understand their impacts to predict how environments they invade may change. Changes in riparian ecosystems should be of special concern as they provide important ecosystem services and are susceptible to disturbance. We examined changes in biogeochemical processes at the terrestrial-aquatic interface at a property that was densely populated by wild pigs. Nitrogen mineralization rates were estimated for floodplain soils disturbed by wild pig rooting, and erosion and accretion of stream bank sediment was recorded to estimate the effects of wild pigs on bank stability. Water quality parameters and fecal bacteria concentrations were measured to determine the impacts of wild pigs on water quality in small forested watersheds. Although the effects of wild pigs may vary depending on local environmental conditions and habitat types, our findings suggest that wild pigs impact nutrient cycling and water quality in riparian areas.
... Following a 2018 Shiga-toxin producing Escherichia coli outbreak linked to romaine lettuce, investigators identified irrigation water contaminated by cattle feces as the probable source (Bottichio et al., 2019). Such a conclusion is not uncommon, and fecal contamination of surface water has been repeatedly identified as the probable cause of enteric disease outbreaks (Johnson, 2006;Ackers et al., 1998;Wachtel et al., 2002;Greene et al., 2008;Barton Behravesh et al., 2011;Food and Drug Administration, 2019;Food and Drug Administration, 2020). As a result, nonpathogenic fecal indicator bacteria (FIBs), like E. coli, are used to assess when and where fecal contaminants, including food and waterborne pathogens, may be present in agricultural and recreational waterways. ...
Since E. coli is considered a fecal indicator in surface water, government water quality standards and industry guidance often rely on E. coli monitoring to identify when there is an increased risk of pathogen contamination of water used for produce production (e.g., for irrigation). However, studies have indicated that E. coli testing can present an economic burden to growers and that time lags between sampling and obtaining results may reduce the utility of these data. Models that predict E. coli levels in agricultural water may provide a mechanism for overcoming these obstacles. Thus, this proof-of-concept study uses previously published datasets to train, test, and compare E. coli predictive models using multiple algorithms and performance measures. Since the collection of different feature data carries specific costs for growers, predictive performance was compared for models built using different feature types [geospatial, water quality, stream traits, and/or weather features]. Model performance was assessed against baseline regression models. Model performance varied considerably with root-mean-squared errors and Kendall’s Tau ranging between 0.37 and 1.03, and 0.07 and 0.55, respectively. Overall, models that included turbidity, rain, and temperature outperformed all other models regardless of the algorithm used. Turbidity and weather factors were also found to drive model accuracy even when other feature types were included in the model. These findings confirm previous conclusions that machine learning models may be useful for predicting when, where, and at what level E. coli (and associated hazards) are likely to be present in preharvest agricultural water sources. This study also identifies specific algorithm-predictor combinations that should be the foci of future efforts to develop deployable models (i.e., models that can be used to guide on-farm decision-making and risk mitigation). When deploying E. coli predictive models in the field, it is important to note that past research indicates an inconsistent relationship between E. coli levels and foodborne pathogen presence. Thus, models that predict E. coli levels in agricultural water may be useful for assessing fecal contamination status and ensuring compliance with regulations but should not be used to assess the risk that specific pathogens of concern (e.g., Salmonella, Listeria) are present.
... However, the consumption of raw lettuce has been closely linked to food poisoning. Although the route of contamination in lettuce has not been established, there were reports of hemolytic-uremic syndrome and bloody diarrhea caused by enterohemorrhagic Escherichia coli serotype O157:H7 contamination [3,4]. In addition, Aeromonas spp. ...
It's indicated the effect of the gut microbiome on both allergy and autoimmunity dermatological diseases by several recent studies. Chronic spontaneous urticaria （CSU）is a disease involving allergy and autoimmunity. There is no report detailing the role of microbiota alterations in its development. This study was performed to identify the fecal microbial composition of CSU patients and investigated the different compositions and potential genetic functions on the fecal microbiota between CSU patients and normal controls. The gut microbiota of CSU patients and healthy individuals were obtained by 16s rRNA massive sequencing. Gut microbiota diversity and composition were compared, and bioinformatics analysis of the differences was performed. Gut microbiota composition showed that Firmicutes, Bacteroidetes, Proteobacteria, and Verrucomicrobia were dominant microbiota in CSU patients. The differential analysis showed that relative abundance of the Proteobacteria (p=0.03), Bacilli (p=0.04), Enterobacteriales (p=0.03), Enterobacteriaceae (p=0.03) was significantly increased in CSU patients. In contrast, the relative abundance of Megamonas, Megasphaera, and Dialister (all p<0.05) in these patients significantly decreased compared with healthy controls. The different microbiological compositions impacted normal gastrointestinal functions based on function prediction, resulting in abnormal pathways, including transport and metabolism. We found CSU patients exhibited gut microbiota dysbiosis compared with healthy controls. Our results indicated CSU is associated with gut microbiota dysbiosis and pointed out the bacterial taxa increased in CSU patients, which might be involved in the pathogenesis of CSU. These results provided clues for future microbial-based therapies on CSU.
... However, the presence of livestock and wildlife in a watershed may reduce water quality as well. Livestock may contaminate stream water through direct contact or from runoff contaminated with feces and urine (Davies-Colley et al., 2004;Line et al., 2000), and subsequent use of contaminated water has been linked to disease outbreaks in humans (Ackers et al., 1998;Jay et al., 2007;Lindqvist et al., 2008). Wildlife species have also been documented as a source of waterborne fecal bacteria pollution. ...
Wild pigs (Sus scrofa) are a highly invasive species in many regions of the world and can act as ecosystem engineers in areas where they are established. In riparian ecosystems, wild pigs may affect water quality parameters and introduce fecal bacteria, although previous studies have reported conflicting results. We propose four conditions that we believe are needed for an accurate assessment of wild pig impacts on water quality and address each one in our study. Water samples were collected between May 2018 and June 2019 in riparian watersheds on a privately owned property in Alabama that was densely populated by wild pigs (treatment) and in watersheds at a nearby national forest without an established population. Samples were analyzed for concentrations of water quality parameters, such as anions and cations, dissolved oxygen, total suspended solids, N, dissolved organic C, and Escherichia coli and other fecal coliforms. An additional 38 samples were analyzed using quantitative polymerase chain reaction for swine fecal bacteroidetes. At treatment watersheds, specific conductivity and concentrations of organic N and C, SO4²⁻, and Ca²⁺ were between 2 and 11 times that of reference watersheds. Escherichia coli values at treatment watersheds were 40 times reference watershed values. DNA from swine fecal bacteroidetes was detected in 70% of treatment samples and 0% of reference samples. Wild pigs are a threat to water quality in riparian areas, and our results indicate that it may be important to control populations upstream of major drinking water sources and recreational areas.
... E. coli O157:H7 is the main EHEC serotype that causes the majority of EHEC human infections. As one of the most commonly found foodborne pathogens, it can be transmitted by contaminated food such as cattle, milk, eggs and vegetables, rice cakes, and others (Ackers et al., 1998;Jacob et al., 2013;Marder et al., 2014). The methods are laborintensive and time-consuming and cannot meet the requirement of rapid monitoring. ...
O157 Escherichia coli is one of the most important foodborne pathogens causing disease even at low cellular numbers. Thus, the early and accurate detection of this pathogen is important. However, due to the formation of viable but non-culturable (VBNC) status, the golden standard culturing methodology fails to identify O157 E. coli once it enters VBNC status. Crossing priming amplification (CPA) is a novel, simple, easy-to-operate detection technology that amplifies DNA with high speed, efficiency, and specificity under isothermal conditions. The objective of this study was to firstly develop and apply a CPA assay with propidium monoazide (PMA) for the rapid detection of the foodborne E. coli O157:H7 in VBNC state. Five primers (2a/1s, 2a, 3a, 4s, and 5a) were specially designed for recognizing three targets, which were rfbE, stx1, and stx2, and evaluated for its effectiveness in detecting VBNC cell of E. coli O157:H7 with detection limits of pure VBNC culture at 103, 105, and 105 colony-forming units (CFUs)/ml for rfbE, stx1, and stx2, respectively, whereas those of food samples (frozen pastry and steamed bread) were 103, 105, and 105 CFUs/ml. The application of the PMA-CPA assay was successfully used on detecting E. coli O157:H7 in VBNC state from food samples. In conclusion, this is the first development of PMA-CPA assay on the detection of VBNC cell, which was found to be useful and a powerful tool for the rapid detection of E. coli O157:H7 in VBNC state. Undoubtedly, the PMA-CPA method can be of high value to the food industry owing to its various advantages such as speed, specificity, sensitivity, and cost-effectiveness.
... The occurrence of multiple foodborne disease outbreaks, over the past two decades, that were potentially linked to the use of contaminated water to irrigate fresh produce has increased concerns over the use of surface water for produce production (Ackers et al., 1998;Centers for Disease Control and Prevention, 2008;Greene et al., 2008;Söderström et al., 2008;Food and Drug Administration, 2018, 2020. For example, the outbreak strains in three, separate E. coli O157:H7 outbreaks linked to romaine lettuce grown in Yuma, Arizona (Food and Drug Administration, 2018), and Salinas, California (Food and Drug Administration, 2019, 2020) were also isolated from canals or reservoirs used to source water for irrigation. ...
While the Food Safety Modernization Act established standards for the use of surface water for produce production, water quality is known to vary over space and time. Targeted approaches for identifying hazards in water that account for this variation may improve growers' ability to address pre-harvest food safety risks. Models that utilize publicly-available data (e.g., land-use, real-time weather) may be useful for developing these approaches. The objective of this study was to use pre-existing datasets collected in 2017 (N = 181 samples) and 2018 (N = 191 samples) to train and test models that predict the likelihood of detecting Salmonella and pathogenic E. coli markers (eaeA, stx) in agricultural water. Four types of features were used to train the models: microbial, physicochemical, spatial and weather. “Full models” were built using all four features types, while “nested models” were built using between one and three types. Twenty learners were used to develop separate full models for each pathogen. Separately, to assess information gain associated with using different feature types, six learners were randomly selected and used to develop nine, nested models each. Performance measures for each model were then calculated and compared against baseline models where E. coli concentration was the sole covariate. In the methods, we outline the advantages and disadvantages of each learner. Overall, full models built using ensemble (e.g., Node Harvest) and “black-box” (e.g., SVMs) learners out-performed full models built using more interpretable learners (e.g., tree- and rule-based learners) for both outcomes. However, nested eaeA-stx models built using interpretable learners and microbial data performed almost as well as these full models. While none of the nested Salmonella models performed as well as the full models, nested models built using spatial data consistently out-performed models that excluded spatial data. These findings demonstrate that machine learning approaches can be used to predict when and where pathogens are likely to be present in agricultural water. This study serves as a proof-of-concept that can be built upon once larger datasets become available and provides guidance on the learner-data combinations that should be the foci of future efforts (e.g., tree-based microbial models for pathogenic E. coli).
... In the United States, STEC O157 outbreaks were first linked to contaminated leafy greens in 1995 and non-O157 STEC outbreaks in 2010 (4)(5)(6). In Canada, STEC O157 outbreaks have been linked to leafy greens since 2012 (Public Health Agency of Canada [PHAC], unpub. ...
Shiga toxin–producing Escherichia coli (STEC) cause substantial and costly illnesses. Leafy greens are the second most common source of foodborne STEC O157 outbreaks. We examined STEC outbreaks linked to leafy greens during 2009–2018 in the United States and Canada. We identified 40 outbreaks, 1,212 illnesses, 77 cases of hemolytic uremic syndrome, and 8 deaths. More outbreaks were linked to romaine lettuce (54%) than to any other type of leafy green. More outbreaks occurred in the fall (45%) and spring (28%) than in other seasons. Barriers in epidemiologic and traceback investigations complicated identification of the ultimate outbreak source. Research on the seasonality of leafy green outbreaks and vulnerability to STEC contamination and bacterial survival dynamics by leafy green type are warranted. Improvements in traceability of leafy greens are also needed. Federal and state health partners, researchers, the leafy green industry, and retailers can work together on interventions to reduce STEC contamination.
... Algunos brotes han sido asociados al consumo de alimentos como agua, hortalizas, melón y cidra (Besser et al., 1993;Millard et al., 1994). Dentro de los principales microorganismos patógenos de humanos que se han encontrado involucrados en estos brotes están las bacterias como Escherichia coli 0157:H7 (Besser et al., 1993;Ackers et al., 1998;Hilborn et al., 1999), Salmonella (Cook et al., 1998;Isaacs et al., 2005) y Listeria monocytogenes (Lin et al., 2002). El agente causal de la mayoría de los brotes de enfermedades ha sido Salmonella spp. ...
... Carrot is a rich source of essential nutritional components and suitable for being used as a fresh-cut vegetable or salad (Vandekinderen et al., 2008). However, a number of outbreaks have been traced to fresh-cut vegetables (Ackers et al., 1998;Greene et al., 2008). In particular, several foodborne illness outbreaks have been associated with carrots (Gaynor et al., 2009;Kangas et al., 2008). ...
In the present study, the synergistic disinfection efficacy of low concentration electrolyzed water (LcEW) (free available chlorine, 4mg/L) combined with brief heat enhancement was evaluated and the bactericidal mechanism was investigated by atomic force microscopy (AFM). The inactivation kinetics of Escherichia coli O157:H7 and Salmonella Typhimurium on organic carrot were fitted with Weibull model to evaluate the synergistic effects. LcEW is effective at inactivating E. coli O157:H7 and S. Typhimurium on organic carrots, and the efficacy is dependent on the temperature. The combined treatment with LcEW at 80°C resulted in decimal reductiontime(TR)of7.42and3.27sforE.coliO157:H7andS.Typhimurium,respectively.Thereactiveoxygen species generated from LcEW were responsible for the microbial inactivation. In addition, AFM observation of E. coli O157:H7 and S. Typhimurium revealed morphological alterations in the bacterial cell structure, which illustrated the damage of cell membrane injury and intracellular component leakage. Quality attributes of carrot treated with LcEW and short-time heating (70°C, 1min) were not significantly different from controls. Compared to the control group, the combined treatment exhibited significantly (P < 0.05) greater inhibition of naturally occurring microbiota on organic carrots during storage at 4°C. Consequently, the application of LcEW combined with short-time heat improved safety of organic carrot, without negatively affecting the sensory properties, which can be explored by the organic industry.
... However, the consumption of raw lettuce has been closely linked to food poisoning. Although the route of contamination in lettuce has not been established, there were reports of hemolytic-uremic syndrome and bloody diarrhea caused by enterohemorrhagic Escherichia coli serotype O157:H7 contamination [3,4]. In addition, Aeromonas spp. ...
Beringraja pulchra, Cham-hong-eo in Korean, is a mottled skate which is belonging to the cartilaginous fish. Although this species is economically valuable in South Korea as an alkaline-fermented food, there are few microbial studies on such fermentation. Here, we analyzed microbial changes and pH before, during, and after fermentation and examined the effect of inoculation by a skin microbiota mixture on the skate fermentation (control vs. treatment). To analyze microbial community, the V4 regions of bacterial 16S rRNA genes from the skates were amplified, sequenced and analyzed. During the skate fermentation, pH and total number of marine bacteria increased in both groups, while microbial diversity decreased after fermentation. Pseudomonas, which was predominant in the initial skate, declined by fermentation (Day 0: 11.39±5.52%; Day 20: 0.61±0.9%), while the abundance of Pseudoalteromonas increased dramatically (Day 0: 1.42±0.41%; Day 20: 64.92±24.15%). From our co-occurrence analysis, the Pseudoalteromonas was positively correlated with Aerococcaceae (r= 0.638) and Moraxella (r= 0.474), which also increased with fermentation, and negatively correlated with Pseudomonas (r= -0.847) during fermentation. There are no critically significant differences between control and treatment. These results revealed that the alkaline fermentation of skates dramatically changed the microbiota, but the initial inoculation by a skin microbiota mixture didn't show critical changes in the final microbial community. Our results extended understanding of microbial interactions and provided the new insights of microbial changes during alkaline fermentation.
... E. coli O157:H7 was responsible for several multistate outbreaks linked to fresh produce including spinach (CDC, 2006), shredded lettuce (Sodha et al., 2011), romaine lettuce (CDC, 2019;CDC, 2020), and spring mix blend (CDC, 2012). Fresh produce associated E. coli O157:H7 outbreaks have been traced back to be originated from the contaminated water (Ackers et al., 1998;Hilborn et al., 1999;Jay et al., 2007). In addition, irrigation water has been identified as the source for Salmonella Newport outbreak in tomatoes (Greene et al., 2008) and Salmonella Saintpaul outbreak in serrano peppers (Hanning, Nutt, & Ricke, 2009). ...
Effect of irrigation with groundwater (GW), primary‐treated wastewater (PTWW), secondary‐treated wastewater (STWW), and roof‐collected rainwater (RCR) on the microbial quality of lettuce cultivars “Annapolis,” “Celinet,” and “Coastline” grown in high tunnel was investigated. Lettuce plants were spray irrigated with irrigation waters once a week for 2 weeks and analyzed for indicator and pathogenic bacteria. PTWW irrigation resulted in the highest Escherichia coli recovery on the lettuce plants (4.7 log MPN/g) as compared to irrigation with other three waters on 0 day postirrigation (dpi). Lettuce cultivars affected the bacterial die‐off rate, where E. coli populations reduced the most by 1.5 log MPN/g on “Annapolis” lettuce on 2 dpi. The STWW and RCR irrigation did not significantly influence indicator bacterial populations on lettuce as compared to GW irrigation. The STWW and RCR containing low populations of indicator bacteria may be suitable for lettuce irrigation in Mid‐Atlantic area without affecting its microbial quality.
... Poor water quality, improper food handling practices and poor hygienic conditions of places of food premises can be a major factor in the contamination of faecal coliform to the food and drinks they served the customer (Pandey, Kass, Soupir, Biswas and Singh, 2014). Other than that, ice can also be one of the sources of contamination of pathogenic bacteria because it is directly in contact with drinks and indirectly by refrigerating foods in the freezer (Ackers et al., 1998). The connection between contaminated ice and enteric diseases and the connection of infections and contaminated ice used in hospitals were mainly reported regarding the issue (Banatvala et al., 2008). ...
Contamination of drinks with E. coli O157:H7 served in food premises such as restaurants can cause haemorrhagic colitis and haemolytic uremic syndrome to humans. The presence or absence of faecal pathogen was demonstrated using coliform group as indicator microorganisms. Therefore, this study was conducted to detect the presence of E. coli O157:H7 in drinking water from food restaurant premise in Kota Samarahan and Kuching to ensure safe and potable drinking water is served to the consumer. A total of thirty (n=30) drink samples including six types of each of the samples are cold plain water, iced tea, iced milo, syrup and iced milk tea. Most Probable Number (MPN) procedure was used in this study to enumerate the MPN values of coliform bacteria in each drink collected. A total of 53.33% (16/30) of the drink samples showed positive E. coli detection. Then, the PCR assay showed 6.25% (one out of 16 isolates) samples were positive and carried stx1 gene produced by E. coli O157:H7 in iced milo sample types. This study showed the drinks collected from food premises was contaminated with faecal contamination, which was not safe to drink by the consumer. Therefore, preventive actions should be taken to prevent foodborne illness outbreak in future
... Escherichia coli O157:H7, and possibly other Shiga-toxinproducing E. coli strains, can contaminate fresh produce in different ways, for example, contaminated manure, irrigation or wash water, contact with infected animals and humans (Beuchat and Ryu 1997). Outbreaks of diseases caused by STEC have been associated with the consumption of leaf lettuce (Ackers et al. 1998), potatoes (Chapman et al. 1997), radish sprouts (Michino et al. 1999; Watanabe et al. 1999), alfalfa sprouts (Anon. 1997; Taormina et al. 1999) and raw vegetables (Pebody et al. 1999). ...
Raw fruits and vegetables have been increasingly associated with human infections caused by Shiga toxin-producing Escherichia coli. This study evaluates the isolation and detection of E. coli O26, O111 and O157 from vegetable samples using immunomagnetic particles.
Standard cultivation and immunomagnetic separation (IMS) procedures were compared. It was found that immunomagnetic particles could efficiently concentrate E. coli cells, detecting significantly more bacteria than with standard cultivation procedures.
Bacteria were detected in 93-100% of the inoculated samples using the IMS procedure, but only 36-93% samples tested by standard cultivation procedures were found to be positive.
The results indicate that E. coli O26, O111 and O157 immunomagnetic particles can be a very useful and efficient tool for the detection of E. coli strains in raw vegetables, and could probably be used with samples of animal origin.
Aims
While fecal indicator bacteria (FIB) testing is used to monitor surface water for potential health hazards, observed variation in FIB levels may depend on scale of analysis (SOA). Two decades of citizen science data, coupled with random effects models, were used to quantify variance in FIB levels attributable to spatial versus temporal factors.
Methods and results
Separately, Bayesian models were used to quantify the ratio of spatial to non-spatial variance in FIB levels and identify associations between environmental factors and FIB levels. Separate analyses were performed for three SOA: waterway, watershed; and statewide. As SOA increased (from waterway to watershed to statewide models), variance attributable to spatial sources generally increased and variance attributable to temporal sources generally decreased. While relationships between FIB levels and environmental factors, such as flow conditions (base versus stormflow), were constant across SOA, the effect of land cover was highly dependent on SOA and consistently smaller than the effect of stormwater infrastructure (e.g. outfalls).
Conclusions
This study demonstrates the importance of SOA when developing water quality monitoring programs or designing future studies to inform water management.
We carried out an investigation to determine the occurrence of Escherichia coli O157:H7 in dairy herds in the Delaware County watershed and to identify the factors that play a role in the likelihood of presence of this organism among animals on these farms. The pathogen poses risk of environmental degradation and health to the inhabitants. A total of 2162 fecal samples were collected per rectum from a representative sample of cattle on 27 dairy farms. The samples were investigated for the presence of E. coli O157:H by initially enriching using a bacteriological media and detection of the pathogen using real‐time polymerase chain reaction technique. Escherichia coli O157:H7 was detected in 74% of the herds in the target population and in 3.7% of samples collected. An additional 54 animals were identified that were infected with O157 non‐H7 strains of E. coli among 15 farms. Several putative risk factors were associated with the detection of the pathogen on the enrolled farms included age, housing calves indoors, group housing for calves, housing calves in the calf barn, presence of dogs on the farm, and housing post‐weaned calves in a cow barn or heifer barn versus a greenhouse. In conclusion, E. coli O157:H7 was present on the dairy farms of Delaware County and may pose a threat to the people that live and work there. The risk associated with the detection of this pathogen could be reduced by adjusting management factors that were identified in this study.
Post-infectious hemolytic uremic syndrome (HUS) is caused by specific pathogens in patients with no identifiable HUS-associated genetic variants or autoantibodies. The majority of HUS cases are due to infection by Shiga toxin (Stx) producing Escherichia coli (STEC). This chapter reviews the epidemiology and pathogenesis of STEC-HUS, including bacterial-derived factors and host responses. STEC disease is characterized by hematological (microangiopathic hemolytic anemia and thrombocytopenia), kidney (acute kidney injury) and extrarenal organ involvement. Clinicians should always strive for an etiological diagnosis through the microbiological or molecular identification of Stx-producing bacteria and Stx or, if negative, serological assays. Treatment of STEC-HUS is supportive; more investigations are needed to evaluate the efficacy of putative preventive and therapeutic measures, such as non-phage-inducing antibiotics, volume expansion and anti-complement agents. The outcome of STEC-HUS is generally favorable, but chronic kidney disease, permanent extrarenal, mainly cerebral complications and death (in less than 5%) occur and long-term follow-up is recommended. The remainder of this chapter highlights rarer forms of post-infectious-HUS due to Shigella dysenteriae type 1, S. pneumoniae, Clostridium spp., influenza virus, SARS-CoV-2 and HIV, and discusses potential interactions between these pathogens and the complement system.KeywordsClostridiumCOVID-19Enterohemorrhagic Escherichia coliHuman immunodeficiency virusInfluenza A(H1N1)NeuraminidasepnHUSShiga toxin
Shigella dysenteriae
STEC
Streptococcus pneumoniae
SARS-CoV-2Thrombotic microangiopathyTMAThrombotic thrombocytopenic purpuraTTPVerocytotoxin
Microbial disease outbreaks related to fresh produce consumption, including leafy green vegetables, have increased in recent years. Where contamination occurs, pathogen persistence may represent a risk for consumers' health. This study analysed the survival of E. coli and L. innocua on lettuce plants watered with contaminated irrigation water via a single irrigation event and within stored irrigation water. Separate lettuce plants (Lactuca sativa var. capitata) were irrigated with water spiked with Log10 7 cfu/mL of each of the two strains and survival assessed via direct enumeration, enrichment and qPCR. In parallel, individual 20 L water microcosms were spiked with Log10 7 cfu/mL of the individual strains and sampled at similar time points. Both strains were observed to survive on lettuce plants up to 28 days after inoculation. Direct quantification by culture methods showed a Log10 4 decrease in the concentration of E. coli 14 days after inoculation, and a Log10 3 decrease in the concentration of L. innocua 10 days after inoculation. E. coli was detected in water samples up to 7 days after inoculation and L. innocua was detected up to 28 days by direct enumeration. Both strains were recovered from enriched samples up to 28 days after inoculation. These results demonstrate that E. coli and L. innocua strains are able to persist on lettuce after a single contamination event up until the plants reach a harvestable state. Furthermore, the persistence of E. coli and L. innocua in water for up to 28 days after inoculation illustrates the potential for multiple plant contamination events from stored irrigation water, emphasising the importance of ensuring that irrigation water is of a high quality.
Escherichia coli O157:H7 is a common food pathogen which has a serious effect on human health. We report here the complete genome sequence of Escherichia coli O157:H7 strain Al Ain, isolated from camel feces in the United Arab Emirates.
Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 mounts specific acid-resistance systems against acid stress, making it more difficult to eradicate in food industry. To date, RNAseq-based analysis focusing on the virulence factors within an acidic environment is restricted to asmall part of virulence gene clusters. In this study E.coli O157:H7 survived HCl stress at pH 3.0 for up to 1 h preceded by acid adaptation at pH 5.5 for 1 h. At the same time, bacteria without stimulus were cultured in neutral TSB broth for 2 h.Then, transcriptome analysis was performed to compare virulence-related genes at neutral and acidic pH. Though transcripts indicated adownshift of the flagellar, fimbriae and LEE-associated genes, the increased expression of adhesin-related genes, iron uptake genes and some potential virulence factors were identified. Comparison of the gene expression with respect to virulence factors revealed strongest cell response to the relevant stress and increased protective response for survival in the acidic pH. This suggests that E.coli O157:H7 might be still virulent following HCl stress.
Accurate data on the incidence of foodborne illness and food histories for affected individuals represent two important barriers to enteric outbreak surveillance and response. Innovative tools to collect and analyze this type of public health intelligence will play an important role in research efforts to improve understanding of the extent, impact of and risk factors for foodborne disease in Canada and around the world. Ethica, a smartphone based application used to acquire, store, and analyze data on human behaviour, provided an opportunity to gather information on the occurrence of enteric illness and the food consumption behaviour of 96 university students over a 10-week period. Nausea or vomiting were reported by 34% of participants, and 29% reported diarrhea at least once during the study using at least one of the available reporting options, but only 7% reported they sought medical care. Real-time data collected through digital images, meal descriptions, and microsurveys were used as a reference to measure the sensitivity and specificity of traditional food history questionnaires administered through an email link after 7 or 18 days (2.5 weeks). The validity of food history data collected after 7 days was found to be consequentially low with sensitivities ranging from 14.3% for sprouts to 100% for leafy greens and specificities ranging from 30.4% for beef to 80.4% for peanuts. Similarly, the sensitivities of questions administered after 18 days ranged from 15.8% for sprouts to 77.8% for tomatoes, with specificities ranging from 21.2% for leafy greens to 92.1% for melons. The impact of recall bias on the accuracy of food history data was found to vary with food type. Bayesian latent class analysis was conducted to determine the sensitivities and specificities in the absence of a true gold standard – the results support those of frequentist approach. These findings serve as a first step in measuring the occurrence of self-reported foodborne illness and the implications of recall bias on outbreak investigations so that these biases can be accounted for research and public health practice.
Background and Aim: Escherichia coli is an important pathogen and microorganism of the normal intestinal flora of humans and animals. One of the important serotypes of E. coli is O157: H7. Because of the excessive and arbitrary use of antibiotics, multiple drug resistance has increased against these organisms. The main problem in treating infections caused by E. coli is its dependence on the administration of a large number of common antibiotics and the resistance of some strains to antibiotics. Phage therapy refers to the therapeutic use of phages to eliminate bacterial infections. In the first step, it is necessary to separate and identify bacteriophages that affect the target bacteria. Therefore, the present study was performed to isolate the phage that was effective on enterohemorrhagic E. coli isolates.
Materials and Methods: In this study, after collection of sewage samples, bacteriophages were isolated by filtration and enrichment in an enterohemorrhagic E. coli overnight culture. The presence of bacteriophage was detected by plaque observation in a double layer agar and confirmed by TEM electron microscopy.
Results & Conclusion: The results of the observation with electron microscopy revealed the presence of bacteriophage with the appearance of the Cystoviridae, Myoviridae and Podoviridae families. Unfortunately, although the titration of phages and molecular study were not performed in the current study due to the lack of budget, we found antibacterial activity of isolated phages using plaque formation observation, and the presence of phages belonging to Cystoviridae, Myoviridae and Podoviridae families was confirmed by TEM microscopy. Therefore, the effective phage against O157: H7 was successfully identified, isolated, and purified.
Photocatalysis disinfection has great potential for irrigation water disinfection to improve fresh produce safety. Titanium dioxide (TiO2) nanoparticle (NP)-embedded cellulose acetate (CA) film has shown effectiveness against Escherichia coli (E. coli) O157:H7 in water. The current study evaluated the effect of natural water compounds on the photo-disinfection efficacy of TiO2 NP-embedded CA film. Humic acid, calcium carbonate (CaCO3), and kaolin clay solutions were prepared at four concentrations, respectively. When concentration increased from 0 to 20 ml/L, inactivation of E. coli O157:H7 in humic acid, CaCO3, and kaolin clay solutions decreased from 6 log to 5, 4, and 2 log CFU/ml, respectively after 3 h treatment. Turbidity, UVT-254, water hardness, total suspended solids (TSS), and total organic carbon (TOC) of the solutions were measured. UVT-254 and turbidity had the highest correlation with the inhibition effect of water compounds on photo-disinfection efficacy. A prediction equation was developed with UVT-254 and water hardness as independent variables to predict photo-disinfection efficacy in natural water. E. coli O157:H7 decreased by 1 and 2.5 log CFU/ml in unfiltered and filtered natural creek water samples after treatment. The results from this study showed promise in the use of TiO2 NP-embedded CA film to inactivate pathogens in natural water. HIGHLIGHTS
Natural water compounds affect TiO2 photo-disinfection efficacy in different degrees.;
UV transmittance and water hardness are important water quality parameters that can affect TiO2 photo-disinfection efficacy.;
Prediction equation was developed to predict TiO2 photo-disinfection efficacy in natural water.;
Filtration is an effective pre-treatment method for improving TiO2 photo-disinfection in natural water.;
RESUME Objectifs : L'objectif de cette étude est d'évaluer l'influence de quelques sources de contamination bactériologiques et d'identifier quelques entérobactéries présentes sur la laitue cultivée à Maroua. Méthodologie et résultats : Les échantillons d'eau, de sol et de laitue ont été prélevés sur 10 sites de production de la laitue dans la ville de Maroua. Les analyses physico-chimiques des eaux d'arrosage portant sur la température, le pH, la conductivité électrique (CE), la salinité et les solides totaux dissous (STD) ont été effectuées. Au cours des analyses microbiologiques, le dénombrement de la flore aérobie mésophile totale, des Clostridium sulfitoréducteurs, des coliformes totaux et fécaux, des salmonelles, des streptocoques fécaux a été effectué et les entérobactéries ont ensuite été identifiées. Les analyses physico-chimiques ont permis d'obtenir des valeurs moyennes de 31.7°C ; 6,67 ; 633,6 µS/cm ; 315,1 ppm et 269,8 mg/mL respectivement pour la température, le pH, CE ; la salinité et STD. Les analyses microbiologiques ont révélé les abondances de FMAT moyennes de 10,8 ; 9,84 et 10,46 LogUFC/mL, respectivement pour les échantillons de sol, de laitue et d'eau. Les streptocoques fécaux ont été détectés dans tous les échantillons de sols ; 80% échantillons de laitue et 70% d'échantillons d'eau. Les concentrations moyennes en coliformes totaux sont de 2,70 LogUFC/g (sol) ; 2,51 LogUFC/g (laitue) et 2,01 LogUFC/mL (eau) tandis que celles des coliformes fécaux sont de 1,74 LogUFC/g (sol) ; 1,80 LogUFC/g (laitue) et 0,55 LogUFC/ml (eau). Les Clostridium sulfitoréducteurs ont été détectés dans tous les échantillons de sol, dans 60% d'échantillons de laitue et dans 20% d'échantillons d'eau. Les espèces d'entérobactéries telles que Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris, Citrobacter frundii, et Serratia marcescens ont été isolées et identifiées de la laitue. Conclusion et application des résultats: La qualité de la laitue consommé à Maroua est ainsi la fortement influencée par le type d'amendement des sols et l'eau d'arrosage. Il est vivement recommandé aux consommateurs et aux vendeurs de désinfecter la laitue avant toute consommation compte tenu de l'abondance de bactéries. Mot clés : Contamination bactériologique, laitue, Entérobactéries, Maroua Maïwore et al., J. Appl. Biosci. 2020 Influence de quelques sources bactériologiques de contamination sur la qualité de la laitue consommée à Maroua (Cameroun), identification des entérobactéries 15927 ABSTRACT Objectives: The objective of this study is to assess the influence of sources of bacterial contamination and to identify some enterobacteria present on lettuce grown in Maroua. Methodology and results: Water, soil and lettuce samples were taken from 10 lettuce production sites in the city of Maroua. Physico-chemical analysis of sprinkler water was performed on temperature, pH, electrical conductivity (CE), salinity and total dissolved solids (TDS). During the microbiological analysis, the enumeration of the total mesophilic aerobic flora (TMAF), sulfite-reducing Clostridium, total and fecal coliforms, salmonella, faecal Streptococcus was carried out and the enterobacteria were then identified. The physico-chemical analyzes revealed average values of 31.7 ° C; 6.67; 633.6 µS / cm; 315.1 ppm and 269.8 mg / mL respectively for temperature, pH, EC; salinity and TDS. Microbiological analyzes revealed the mean TMAF abundances of 10.8; 9.84 and 10.46 LogUFC/mL, respectively for soil, lettuce and water samples. Faecal streptococci were detected in all soil samples; 80% lettuce samples and 70% water samples. The average total coliform concentrations are 2.70 LogUFC/g (soil); 2.51 LogUFC/g (lettuce) and 2.01 LogUFC/mL (water) while those of fecal coliforms are 1.74 LogUFC/g (soil); 1.80 LogUFC/g (lettuce) and 0.55 LogUFC/ml (water). sulfite-reducing Clostridium was detected in all soil samples, in 60% of lettuce samples and in 20% of water samples. Enterobacteria such as Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris, Citrobacter frundii, and Serratia marcescens were isolated and identified from lettuce. Conclusion and application of results: The quality of the lettuce consumed in Maroua is thus strongly influenced by the type of soil improvement and the irrigation water. Consumers and sellers are strongly advised to disinfect lettuce before consumption due to the abundance of bacteria.
The assessment was based on interviews result and experiment laboratory assay with the three organic kyuri farmers in Saga City focus prevention activities of microbiological contamination. Each farm the 21 samples (soil, kyuri seedlings, natural fertilizer, and water resource) were taken during six times visited or one cultivation production cycle. The object was a focus on hygiene attribute (coliforms) and safety (Salmonella spp and E. coli O157: H7), the evaluation activities of farmers' food safety practice used GAP standard as an indicator. The laboratory results in both of three kyuri farmers, coliforms ranging from 3.0 to 4.7 log 10 cfu/g, E.coli O157: H7 was detected only at the farm 3 and Salmonella spp was not detected. The evaluating activities through self-assessment tool describe all three farms have two major hazards focus, one is chemical control such as synthetic substances uses, pesticide residue and chemical contaminations, two is a microbial hazard due to contact with raw material, and natural characteristics. The overall study, the farmers in the middle level of application food safety practice.
Application of organic amendments to agricultural land improves soil quality and provides nutrients essential for plant growth; however, they are also a reservoir for zoonotic pathogens whose presence poses a significant risk to public health. The persistence of bacteria in manure-amended soil, and differences in manure handling practices, are important issues from a food safety perspective. The primary objective of this study was to quantitatively summarize the variations in the rate of decline of Escherichia coli and Salmonella spp. in manure-amended soil under laboratory and field conditions, and to assess the impact of environmental factors. Available literature data on persistence of E. coli and Salmonella spp. in manure-amended soil from 42 primary research studies were extracted and statistically analyzed using a mixed-effect regression model. The results indicated that temperature (soil and air combined) was the most prominent factor affecting persistence of both E. coli and Salmonella spp. under laboratory conditions (P < 0.001), and of E. coli under field conditions (P < 0.05). The time required for a log reduction of E. coli under field conditions was significantly higher at low temperature (0 to 10°C) than at high temperature (greater than 20°C) (P < 0.05). In addition, application method was identified as a significant factor, with manure incorporation to soil inducing longer survival compared with surface application by approximately 1.2 times. The significant variation observed among primary research studies of bacterial persistence has highlighted that mitigation strategies associated with the use of manures in fresh produce production need to be improved by addressing factors such as climate, soil management, application method, and initial microbial levels. These findings may be used to support guidelines establishing exclusion periods between manure fertilization and the grazing or harvesting of crops, and may be useful for the generation of quantitative microbial risk models for fresh produce.
HIGHLIGHTS
Les Escherichia coli entérohémorragiques (EHEC) sont responsables de toxi– infections alimentaires conduisant à des co lites hémorragiques pouvant se compliquer d’un syndrome hémolytique et urémique. Le facteur ma jeur de pathogénicité est la production de Shiga-toxines (Stx), dont la t oxine Stx2. Nous avons étudié la production de toxine Stx2 in vitro par des souches STEC provenant de diverses or igines (bovine ou clin ique), appartenant à divers séropathotypes, et coda nt pour différents variants St x2. Nous avons montré que les souches O157:H7 les plus pathogènes possèdent le variant stx 2 et produisent de fortes quantité de Stx2 en conditions basales comme en pr ésence d’un inducteur du système SOS. Les souches non-O157 présentant ces caractéristique s pourraient représenter un risque pour la santé humaine. Nous avons ensuite étudié l’effet de molécules prés entes dans le tube digestif sur la synthèse de Stx2 par E. coli O157:H7. Les auto-inducteur s AI-2 et AI-3 du quorum sensing, produits par le microbi ote intestinal, n’influencent pa s la synthèse de Stx2, non plus que l’hormone intestinale norépin éphrine. Cependant, la protéi ne régulatrice QseA impliquée dans une voie de signalisation par le quorum sensing serait un activateur transcriptionnel de stx 2 . Enfin, nous avons étudié la production de Stx2 par la souche EHEC O157:H7 EDL 933 dans un milieu se rapprochant le plus possible de celui rencontré in vivo par les EHEC, en particulier grâce à un modèle de rats associés au microbiote intestinal humain. Nous avons ainsi montré que le microbiote hum ain inhibe la transcription de stx2 par l’inhibition de la transcription de recA même lors de l’induction du système SOS, et que cette inhibition peut être en partie attribuée à l’espèce Bacteroides thetaiotaomicron
Fresh produce shall be thoroughly washed at the retail level prior to serving to the consumer with potable water. Foodborne pathogens if present on a product may transfer to the wash water and cross-contaminate other products immersed in the water. Typically, an entire carton of lettuce (24 heads) is washed together increasing the likelihood of cross-contamination due to the close contact between each head. This study aimed to compare the effects of two wash batch volumes – “low” (8 heads) and “high” (24 heads) on the efficacy of two commercial water antimicrobials and cross-contamination. Red leaf lettuce was spot-inoculated (~5.0 log CFU/g) with Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes. In the first batch of washing, inoculated lettuce was washed with non-inoculated lettuce, followed by reuse of the water/antimicrobials twice washing only non-inoculated lettuce. Samples of inoculated and non-inoculated lettuce were collected to determine aerobic plate count (APC) as well as the populations of STEC and L. monocytogenes. Microbiological analysis of the wash water was also conducted. Wash volume (8 versus 24 lettuce heads) had limited effects on the antimicrobial activities of the inventions evaluated. Instead, high-volume wash increased the rate of cross-contamination between non-inoculated and inoculated lettuce, and cross-contamination of non-inoculated lettuce through wash water reuse. Retailers should consider volume of product processed per batch, reuse of wash water, and use of an appropriate water antimicrobial in consideration of mitigating potential product cross-contamination.
The fate of enterohemorrhagic Escherichia coli O157:H7 was determined in three different lots of commercial mayonnaise, including four different samples from a lot implicated in an outbreak of E. coli O157:H7 infection. The initial pH of the products ranged from 3.6 to 3.9. Products were inoculated with 6.5 × 103 E. coli O157:H7/g and incubated at 5 or 20°C. Escherichia coli O157:H7 did not grow at either temperature but survived for 34 to 55 days at 5°C and for 8 to 21 days at 20°C, depending on the lot. Survival was greatest in real mayonnaise purchased at retail among six mayonnaise samples which included a reduced calorie mayonnaise. Escherichia coli O157:H7 populations decreased between 2- and 100-fold by 3 weeks at 5°C, and between 10- and 1,000-fold by 7 days at 20°C. There was little or no change in pH (<0.1 unit), aerobic plate count, mold and yeast count or Lactobacillus count (<1 log10 CFU/g) for the duration of the study. Commercial mayonnaise manufactured under good manufacturing practices is not a public health concern. Abusive handling of mayonnaise resulting in cross-contamination with E. coli O157:H7-contaminated food or contamination by an infected foodhandler is the principal basis for concern.
The first recognized outbreak of haemorrhagic colitis due to Escherichia coli O 157.H7 in the United Kingdom affected at least 24 persons living in East Anglia over a 2-week period. The illnesses were characterized by severe abdominal pain and bloody diarrhoea of short duration. Eleven patients were admitted to hospital and there was one death. Patients were mainly adult women who had not eaten out of the home in the 2 weeks before onset. Unlike previously reported outbreaks hamburgers were not the vehicle of infection, and a case-control study suggested that handling vegetables, and particularly potatoes, was the important risk factor.
Escherichia coli O157.H7 was found in 10 of 3570 (0.28%) faecal samples from dairy cattle in 5 of 60 herds (8.3%). Several tentative associations with manure handling and feeding management practices on dairy farms were identified. Faecal/urine slurry samples, bulk milk samples, and milk filters from dairy herds were negative for E. coli O157.H7. E. coli O157.H7 was also isolated from 10 of 1412 (0.71%) faecal samples from pastured beef cattle in 4 of 25 (16%) herds. The prevalence of E. coli O157.H7 excretion in feedlot beef cattle was 2 of 600 (0.33%). The identification of cattle management practices associated with colonization of cattle by E. coli O157.H7 suggests the possibility that human E. coli O157.H7 exposure may be reduced by cattle management procedures.
Shiga-like-toxin (SLT)-producing Escherichia coli strains, especially serotype O157:H7, are important causes of bloody diarrhea and are associated with the development of hemolytic-uremic syndrome (HUS). Enzyme-linked immunosorbent assays (ELISAs) were developed for the serologic detection of immunoglobulin M (IgM), IgG, and IgA to Shiga toxin (ST) and SLT-I, IgG to SLT-II, and IgM and IgG reactive against E. coli O157 lipopolysaccharide (LPS). Serum samples were collected from 27 HUS patients (25 pediatric and 2 adult) and tested in the ELISAs. Of 27 patients, 10 (37%) were positive for at least one class of antibody to ST/SLT-I. None of the patients were positive for IgG antibody to SLT-II. Twenty-one of the 27 patients (78%) were positive for antibody to E. coli O157 LPS; 19 of 27 (70%) were positive for IgM, and 20 of 27 (74%) were positive for IgG. None of 48 control serum samples were positive in any of the toxin assays, and only 1 of 48 (2%) and 2 of 48 (4%) were positive for IgM and IgG, respectively, to E. coli O157 LPS. Twelve of the 24 patients (50%) from whom stool specimens were collected were positive by culture for E. coli O157. Overall, serology and culture produced confirmation of infection by SLT-producing organisms in 23 of 27 (85%) HUS patients. A combination of ELISA for antibodies to E. coli O157 LPS and culture provided evidence for 22 of 27 (82%) of these patients. The results indicate that while ELISAs for ST/SLT-I and SLT-II antibodies were of limited diagnostic value, the ELISAs for IgM and IgG to E. coli O157 LPS provided valuable and sensitive adjuncts to culture.
The influence of modified-atmosphere packaging, storage temperature, and time on survival and growth of Escherichia coli O157:H7 inoculated onto shredded lettuce, sliced cucumber, and shredded carrot was determined. Growth of psychotrophic and mesophilic microorganisms and changes in pH and sensory qualities of vegetables, as judged by subjective evaluation, were also monitored. Packaging under an atmosphere containing 3% oxygen and 97% nitrogen had no apparent effect on populations of E. coli O157:H7, psychotrophs, or mesophiles. Populations of viable E. coli O157:H7 declined on vegetables stored at 5 degrees C and increased on vegetables stored at 12 and 21 degrees C for up to 14 days. The most rapid increases in populations of E. coli O157:H7 occurred on lettuce and cucumbers stored at 21 degrees C. These results suggest that an unknown factor(s) associated with carrots may inhibit the growth of E. coli O157:H7. The reduction in pH of vegetables was correlated with initial increases in populations of E. coli O157:H7 and naturally occurring microfloras. Eventual decreases in E. coli O157:H7 in some samples, e.g., those stored at 21 degrees C, are attributed to the toxic effect of accumulated acids. Changes in visual appearance of vegetables were not influenced substantially by growth of E. coli O157:H7. The ability of E. coli O157:H7 to growth on raw salad vegetables subjected to processing and storage conditions simulating those routinely used in commercial practice has been demonstrated.
The sensitivities of several plating and broth enrichment methods for the detection of Escherichia coli O157:H7 in (i) bovine fecal samples directly inoculated with E. coli O157:H7, (ii) fecal samples from cattle in herds previously positive for E. coli O157:H7, and (iii) fecal samples from calves shedding E. coli O157:H7 after experimental oral inoculation were compared. Three enrichment protocols and three plating protocols were evaluated with directly inoculated fecal samples. All broth enrichment methods were superior to direct plating when they were combined with subsequent plating on sorbitol-MacConkey with cefixime and tellurite (SMACct). SMACct was the most sensitive plating medium, and the three alternative broth enrichment methods gave similar improvements in sensitivity. Of 351 fecal samples from known positive herds, 24 samples (6.8%) were positive by one or more methods. By the most sensitive plating method, cultures of 10-g samples were slightly more sensitive (19 of 351 [5.4%]) than cotton-tipped swab fecal samples (14 of 351 [4.0%]); however, this difference was not significant. For samples from calves orally inoculated with E. coli O157:H7, separation by immunomagnetic beads was slightly more sensitive (79%) than broth enrichment followed by plating at two dilutions (10(-3) and 10(-4)) (71%); however, this difference was not significant. The combination of overnight enrichment of swab fecal samples (0.1 g) and plating on SMACct at two dilutions (10(-3) and 10(-4)) appears to be a sensitive method for detection in large-scale studies involving hundreds of samples per week.
We found naturally occurring, potentially virulent Escherichia coli O157:H7 strains in sheep. The incidence of E. coli O157:H7 was transient and ranged from 31% of sheep in June to none in November. The use of a sensitive culture technique and the choice of the proper sampling season were both essential for detecting this bacterium in sheep. DNA hybridizations showed that 80% of the E. coli O157:H7 isolates had at least two of the Shiga-like toxin types I or II or the attaching-effacing lesion genes.
Shiga-like toxin-producingEscherichia coli O157:H7 are important causes of bloody diarrhea and hemolytic uremic syndrome. To facilitate the epidemiologic study of these organisms, we developed enzyme-linked immunosorbent assays (ELISAs) for antibodies to Shiga-like toxin I (SLT I), Shiga-like toxin II (SLT II), andE. coli O157 lipopolysaccharide (LPS). We tested serum samples from 83 patients in two outbreaks ofE. coli O157:H7 diarrhea and from 66 well persons. Forty-three patients (52%) had at least one serum sample positive for anti-O157 LPS antibodies; among 26 culture-confirmed patients, 24 (92%) had at least one positive serum sample. Two (3%) of 66 control sera had positive anti-O157 LPS titers. ELISA results for SLT I and II were compared with those of HeLa cell cytotoxicity neutralization assays on both patient and control sera. Neutralization assays detected anti-SLT I antibodies in at least one serum sample from each of 17 (20%) patients and 7 (10.6%) controls, while 16 (19%) patients and 7 controls had positive titers by anti-SLT I ELISA. Although all serum samples, including control sera, showed nonspecific neutralization of SLT II, no antibody titers to SLT II were detected by either neutralization or ELISA. These results indicate that ELISAs for SLT I and SLT II antibodies are comparable to HeLa cell cytotoxicity neutralization assays. Both the ELISAs and neutralization assays are insensitive in detecting infected patients. However, the ELISA for antibodies toE. coli O157 LPS is both sensitive and specific, and may be more useful than assays for antitoxic antibodies in detecting persons withE. coli O157:H7 infection.
To describe and determine the source of a large outbreak of Escherichia coli O157:H7 (ECO157) infections in Missouri.
A case-control study and a household survey.
A small city in a rural Missouri township that had an unchlorinated water supply.
Case patients were residents of or visitors to Burdine Township with bloody diarrhea or diarrhea and abdominal cramps occurring between 15 December 1989 and 20 January 1990.
Escherichia coli O157 was isolated from 21 stool specimens. All isolates were resistant to sulfisoxazole, tetracycline, and streptomycin; produced Shiga-like toxins I and II; and had one 60-megadalton plasmid.
Among the 243 case patients, 86 had bloody stools, 32 were hospitalized, 4 died, and 2 had the hemolytic uremic syndrome. In the case-control study, no food was associated with illness, but ill persons had drunk more municipal water than had controls (P = 0.04). The survey showed that, during the peak of the outbreak, bloody diarrhea was 18.2 times more likely to occur in persons living inside the city and using municipal water than in persons living outside the city and using private well water (P = 0.001). Shortly before the peak of the outbreak, 45 water meters were replaced, and two water mains ruptured. The number of new cases declined rapidly after residents were ordered to boil water and after chlorination of the water supply.
This was the largest outbreak of ECO157 infections, the first due to a multiply resistant organism, and the first shown to be transmitted by water. System-wide chlorination as well as hyperchlorination during repairs might have prevented this outbreak. Both bloody and nonbloody diarrhea may be common manifestations of this infection, which is probably underdiagnosed because of the failure of routine stool cultures to identify the organism. Cities with deteriorating water systems using untreated water risk widespread illness from contaminated drinking water.
Escherichia coli serotype O157:H7 is a recently recognized human pathogen associated with hemorrhagic colitis. Unlike most E. coli strains, E. coli O157:H7 does not ferment sorbitol. Therefore, the efficacy of MacConkey agar containing sorbitol (SMAC medium) instead of lactose as a differential medium for the detection of E. coli O157:H7 in stool cultures was determined in comparison with MacConkey agar. The relative frequency of non-sorbitol-fermenting (NSF) organisms other than E. coli O157:H7 in feces was low at 10 to 20% (95% confidence limits), and NSF organisms also occurred mostly in small numbers. In a field trial involving over 1,000 diarrheal stools, E. coli O157:H7 was isolated from 18 stools, all of which were from patients with bloody diarrhea. In every instance, the growth of E. coli O157:H7 on SMAC medium was heavy and occurred in almost pure culture as colorless NSF colonies in contrast to fecal flora, which are mostly sorbitol fermenting and hence appear pink on this medium, whereas on MacConkey agar cultures, the growth of E. coli O157:H7 was indistinguishable from fecal flora. SMAC medium permitted ready recognition of E. coli O157:H7 in stool cultures. Detection of E. coli O157:H7 on SMAC medium had a sensitivity of 100%, a specificity of 85%, and an accuracy of 86%. SMAC medium stool culture is a simple, inexpensive, rapid, and reliable means of detecting E. coli O157:H7, and we recommend routine use of SMAC medium especially for culturing bloody stools.
Two hundred thirty-three isolates of Escherichia coli O157:H7 were analyzed by both pulsed-field gel electrophoresis (PFGE) and bacteriophage typing. All 26 isolates from persons whose illness was associated with a recent multistate outbreak of E. coli O157:H7 infections linked to the consumption of undercooked hamburgers and all 27 isolates from incriminated lots of hamburger meat had the same phage type and the same PFGE pattern. Twenty-five of 74 E. coli O157:H7 isolates from Washington State and 10 of 27 isolates from other states obtained during the 6 months before the outbreak had the same phage type as the outbreak strain, but only 1 isolate had the same PFGE pattern. PFGE thus appeared to be a more sensitive method than bacteriophage typing for distinguishing outbreak and non-outbreak-related strains. The PFGE patterns of seven preoutbreak sporadic isolates and five sporadic isolates from the outbreak period differed from that of the outbreak strain by a single band, making it difficult to identify these isolates as outbreak or non-outbreak related. Phage typing and PFGE with additional enzymes were helpful in resolving this problem. While not as sensitive as PFGE, phage typing was helpful in interpreting PFGE data and could have been used as a simple, rapid screen to eliminate the need for performing PFGE on unrelated isolates.
Escherichia coli O157:H7 causes hemorrhagic colitis and the hemolytic uremic syndrome. In the fall of 1991, an outbreak of E coli O157:H7 infections in southeastern Massachusetts provided an opportunity to identify transmission by a seemingly unlikely vehicle.
Case-control study to determine the vehicle of infection. New England cider producers were surveyed to assess production practices and determined the survival time of E coli O157:H7 organisms in apple cider.
Illness was significantly associated with drinking one brand of apple cider. Thirteen (72%) of 18 patients but only 16 (33%) of 49 controls reported drinking apple cider in the week before illness began (odds ratio [OR], 8.3; 95% confidence interval [CI], 1.8 to 39.7). Among those who drank cider, 12 (92%) of 13 patients compared with two (13%) of 16 controls drank cider from cider mill A (lower 95% CI, 2.9; P < .01). This mill pressed cider in a manner similar to that used by other small cider producers: apples were not washed, cider was not pasteurized, and no preservatives were added. In the laboratory, E coli O157:H7 organisms survived for 20 days in unpreserved refrigerated apple cider. Addition of sodium benzoate 0.1% reduced survival to less than 7 days.
Fresh-pressed, unpreserved apple cider can transmit E coli O157:H7 organisms, which cause severe infections. Risk of transmission can be reduced by washing and brushing apples before pressing, and preserving cider with sodium benzoate. Consumers can reduce their risk by only drinking cider made from apples that have been washed and brushed.
Dairy cattle have been identified as a principal reservoir of Escherichia coli O157:H7. The fate of this pathogen in bovine feces at 5, 22, and 37 degrees C was determined. Two levels of inocula (10(3) and 10(5) CFU/g) of a mixture of five nalidixic acid-resistant E. coli O157:H7 strains were used. E. coli O157:H7 survived at 37 degrees C for 42 and 49 days with low and high inocula, respectively, and at 22 degrees C for 49 and 56 days with low and high inocula, respectively. Fecal samples at both temperatures had low moisture contents (about 10%) and water activities ( < 0.5) near the end of the study. E. coli O157:H7 at 5 degrees C survived for 63 to 70 days, with the moisture content (74%) of feces remaining high through the study. Chromosomal DNA fingerprinting of E. coli O157:H7 isolates surviving near the completion of the study revealed that the human isolate strain 932 was the only surviving strain at 22 or 37 degrees C. All five strains were isolated near the end of incubation from feces held at 5 degrees C. Isolates at each temperature were still capable of producing both verotoxin 1 and verotoxin 2. Results indicate that E. coli O157:H7 can survive in feces for a long period of time and retain its ability to produce verotoxins. Hence, bovine feces are a potential vehicle for transmitting E. coli O157:H7 to cattle, food, and the environment. Appropriate handling of bovine feces is important to control the spread of this pathogen.
Epidemiologic research Belbreak due to contaminated salad — Idaho
- D Kleinbaum
- L Kupper
- Morgenstern
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Investigation of a lettuce-borne prevalence of Escherichia coli O157:H7 in dairy and beef cattle in Washington State Escherichia coli O157:H7 outbreak in a hospital [abstract J106]
- R Davidson
- P Proctor
- M Preston
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Investigation of largescale outbreak of Escherichia coli O157:H7 infection among school Recent advances in verocytotoxin-producing Escherichia coli infections
- H Michino
- K Araki
- S Minami
- S Takaya
- N- Sakai
- Karmali Ma
- Goglio
Michino H, Araki K, Minami S, Takaya S, Sakai N. Investigation of largescale outbreak of Escherichia coli O157:H7 infection among school- Karmali MA, Goglio AG, eds. Recent advances in verocytotoxin-producing Escherichia coli infections. Amsterdam: Elsevier Science, 1994: children in Sakai City, 1996 [abstract]. In: Abstracts of the 32nd Joint Conference United States – Japan Cooperative Medical Science Pro-7 – 12.
Survival and growth of Eschegram , Cholera and Related Diarrheal Diseases Panel (Nagasaki, Japan) richia coli O157:H7 on salad vegetables
- Um Abdul-Raof
- Lr Beuchat
- Ammar
Abdul-Raof UM, Beuchat LR, Ammar MS. Survival and growth of Eschegram, Cholera and Related Diarrheal Diseases Panel (Nagasaki, Japan), 1996:84–8. richia coli O157:H7 on salad vegetables. Appl Environ Microbiol 1993; 59:1999 – 2006.
Outbreak of E. coli O157: H7 infections among boy scouts in Maine [abstract K44] In: Program Western Growers Association, 1997. / 9d46$$ju40 04-14-98 18:39:54 jinfal UC
- J Mermin
- P Mead
- K Gensheimer
- Griffin
Mermin J, Mead P, Gensheimer K, Griffin P. Outbreak of E. coli O157: H7 infections among boy scouts in Maine [abstract K44]. In: Program Western Growers Association, 1997. / 9d46$$ju40 04-14-98 18:39:54 jinfal UC: J Infect by guest on July 13, 2011 jid.oxfordjournals.org Downloaded from
Investigation of large-scale outbreak of Escherichia coli O157:H7 infection among school-children in Sakai City
- H Michino
- K Araki
- S Minami
- S Takaya
- Sakai
Michino H, Araki K, Minami S, Takaya S, Sakai N. Investigation of large-scale outbreak of Escherichia coli O157:H7 infection among school-children in Sakai City, 1996 [abstract]. In: Abstracts of the 32nd Joint Conference United States–Japan Cooperative Medical Science Pro-gram, Cholera and Related Diarrheal Diseases Panel (Nagasaki, Japan), 1996:84–8
Escherichia coli O157:H7 diarrhea out-break due to contaminated salad—Idaho
- Cg Hahn
- M Snell
- B Jue
Hahn CG, Snell M, Jue B, et al. Escherichia coli O157:H7 diarrhea out-break due to contaminated salad—Idaho, 1995 [abstract]. In: Abstracts of the 45th Annual Epidemic Intelligence Service Conference. Atlanta: Centers for Disease Control and Prevention, 1996:18
A multistateoutbreak ofEscherichia coli O157:H7 infections associated with mesclun mix lettuce [abstract] In: Abstracts of the 46th Annual Epidemic Intelligence Service Confer-ence
- Ed Hilborn
- J Mermin
- P Mshar
Hilborn ED,Mermin J,Mshar P,et al.A multistateoutbreak ofEscherichia coli O157:H7 infections associated with mesclun mix lettuce [abstract]. In: Abstracts of the 46th Annual Epidemic Intelligence Service Confer-ence. Atlanta: Centers for Disease Control and Prevention, 1997:33
Survival and growth of Eschegram , Cholera and Related Diarrheal Diseases Panel
- Um Abdul-Raof
- Lr Beuchat
- Ms Ammar
Abdul-Raof UM, Beuchat LR, Ammar MS. Survival and growth of Eschegram, Cholera and Related Diarrheal Diseases Panel (Nagasaki, Japan),
1996:84–8.
A waterborne outbreak in biologically plausible vehicle because growth studies on lettuce Missouri of Escherichia coli O157:H7 associated with bloody diarrhea have shown that bacterial populations of E. coli O157:H7 inand death
- Dl Swerdlow
- Ba Woodruff
- Rc Brady
have been harvested, distributed, and consumed. Lettuce is a
3. Swerdlow DL, Woodruff BA, Brady RC, et al. A waterborne outbreak in
biologically plausible vehicle because growth studies on lettuce
Missouri of Escherichia coli O157:H7 associated with bloody diarrhea
have shown that bacterial populations of E. coli O157:H7 inand death. Ann Intern Med 1992; 117:812 – 9.
Outbreak of E. coli O157: H7 infections among boy scouts in Maine
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The risk of such outbreaks may 9 Sorbitol-MacConkey medium for detection of Eschbe reduced by the use of uncontaminated irrigation water and erichia coli O157:H7 associated with hemorrhagic colitis
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