Fig 2 - uploaded by Aleksandra Maria Kocot
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The cell counts of L. monocytogenes A1 ( ) and E. coli A14 ( ) in dualspecies biofilms formed in batch (A) and fed-batch (B) system for 48 h. The bars represent the mean values ± standard deviations. Asterisks indicate significant differences between counts of L. monocytogenes A1 and E. coli A14 (p < 0.05).
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Biofilms pose a serious challenge to the food industry. Higher resistance of biofilms to any external stimuli is a major hindrance for their eradication. In this study, we compared the growth dynamics and benzalkonium chloride (BAC) resistance of dual species Listeria monocytogenes-Escherichia coli 48 h biofilms formed on stainless steel (SS) coupo...
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Context 1
... of biofilm formation on SS coupons in batch and fed-batch conditions are shown in Fig. 2. The number of cells of both strains increased in the following hours of biofilm growth, regardless of the experimental conditions and after 48 h of biofilm development reached the values of 6.98 and 8.03 log CFU/coupon and 4.98 and 6.35 log CFU/ coupon for L. monocytogenes and E. coli under batch and fed-batch conditions, ...
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Listeria monocytogenes is considered as a foodborne pathogen of serious concern capable to form multispecies biofilms with other bacterial species, such as Pseudomonas spp., adhered onto stainless steel (SS) surfaces. In an attempt to link the biofilms’ morphology and resistance to biocides, dual-species biofilms of L. monocytogenes, in co-culture...
Citations
... Our results are in good agreement with these data. It is important to note that batch-fed conditions can significantly increase the resistance of bacterial biofilm (e.g., E. coli) to BAC [41]. Below-optimal often leads to a decrease in enzyme activity and slower microbial metabolism. ...
Benzalkonium chloride (BAC) is one of the most commonly used quaternary ammonium compounds in the pharmaceutical, cosmetic, and food industries. The aim of our study was to compare the physiological responses of Escherichia coli MSCL 332, Pseudomonas putida MCCL 650, and Staphylococcus epidermidis MSCL 333 on 50 mg/L BAC in rich and poor medium (100% and 5% tryptone soya broth (TSB)) in the temperature range from 8 °C to 37 °C, under static and shaking conditions. A high-throughput, 96-well microplate method was used to compare a broad range of cultivation conditions. The effect of BAC on growth, biofilm formation activity, and dehydrogenase and fluorescein diacetate hydrolysis activity was evaluated. Addition of BAC to 100% TSB inhibited biofilm formation at 37 °C by 2.4, 1.8, and 1.6 times for E. coli, P. putida, and S. epidermidis, respectively. In turn, BAC stimulated biofilm formation in E. coli in 5% TSB at 37 °C and 100% TSB at 8 °C, i.e., 1.4 and 1.3 times, respectively. Statistical optimization of broth composition with emphasis on biofilm formation and further testing under experimental conditions was performed with P. putida.
... Among cationic antimicrobial agents, quaternary ammonium compounds (QACs) like BAC can effectively remove the mixed biofilm of L. monocytogenes and E. coli O157:H7 (Kocot, Wróblewska, and Cabo 2021). However, QACs were susceptible to resistance that mediated through multidrug efflux pumps (Heir, Sundheim, and Holck 1999). ...
Listeria monocytogenes is an important foodborne pathogen. It can adhere to food or food contact surface for a long time and form biofilm, which will lead to equipment damage, food deterioration, and even human diseases. As the main form of bacteria to survive, the mixed biofilms often exhibit higher resistance to disinfectants and antibiotics, including the mixed biofilms formed by L. monocytogenes and other bacteria. However, the structure and interspecific interaction of the mixed biofilms are very complex. It remains to be explored what role the mixed biofilm could play in the food industry. In this review, we summarized the formation and influence factors of the mixed biofilm developed by L. monocytogenes and other bacteria, as well as the interspecific interactions and the novel control measures in recent years. Moreover, the future control strategies are prospected, in order to provide theoretical basis and reference for the research of the mixed biofilms and the targeted control measures.
... A major disadvantage of research on biofilms is also their formation under laboratory conditions in a static system, which does not reflect the conditions of a food industry plant, where cell adhesion is hindered due to the flow of semifinished products as well as by washing and disinfection procedures. Under these conditions they form biofilms with greater resistance than their planktonic counterparts (Kocot et al., 2021), and further research is needed on the application of phages against biofilms, taking into account the conditions that better mimic the conditions of food production plants. Alternatively, a newer avenue of investigation is the use of phage lysins, which are less prone to promoting the development of resistance and often active against biofilms (Fischetti, 2018). ...
One of the biggest challenges faced by food producers is ensuring microbiological safety. Despite strict criteria for food products, foodborne diseases are a global problem and pose a real risk to consumers. Therefore, it is necessary to identify new and more effective methods for eliminating pathogens from food and the food processing environment. According to the European Food Safety Authority (EFSA), the most common foodborne diseases are caused by Campylobacter, Salmonella, Yersinia, Escherichia coli, and Listeria. Out of the five listed, four are Gram‐negative bacteria. Our review focuses on the use of bacteriophages, which are ubiquitous bacterial viruses, and bacteriophage endolysins to eliminate Gram‐negative pathogens. Endolysins cleave specific bonds within the peptidoglycan (PG) of the bacterial cell, causing the cell to burst. Single phages or phage cocktails, which are, in some instances, commercially available products, eliminate pathogenic bacteria in livestock and various food matrices. Endolysins have matured as the most advanced class of antibacterial agents in the clinical sector, but their use in food protection is highly unexplored. Advanced molecular engineering techniques, different formulations, protein encapsulation, and the addition of outer membrane (OM) permeabilization agents enhance the activity of lysins against Gram‐negative pathogens. This creates space for groundbreaking research on the use of lysins in the food sector.
... In this line, several authors have considered the biofilm complexity and its antimicrobial resistance as two related phenomena (Pan et al., 2006;Saá Ibusquiza et al., 2012a). On the contrary, Kocot et al. (2021) demonstrated that in L. monocytogenes-E. coli dualspecies biofilms cultured in a batch (i.e., polystyrene plates) or fed-batch (i.e. ...
Listeria monocytogenes is considered as a foodborne pathogen of serious concern capable to form multispecies biofilms with other bacterial species, such as Pseudomonas spp., adhered onto stainless steel (SS) surfaces. In an attempt to link the biofilms’ morphology and resistance to biocides, dual-species biofilms of L. monocytogenes, in co-culture with either Pseudomonas aeruginosa, P. fluorescens or P. putida, were assayed to ascertain their morphological characteristics and resistance towards benzalkonium chloride (BAC) and neutral electrolyzed water (NEW). Epifluorescence microscopy analysis revealed that each dual-species biofilms was distributed differently over the SS surface and that these differences were attributable to the presence of Pseudomonas spp. Confocal laser scanning microscopy (CLSM) assays demonstrated that despite these differences in distribution all biofilms had similar maximum thicknesses. Along with this, colocalization analyses showed a strong trend of L. monocytogenes to share location within the biofilm with all Pseudomonas assayed whilst the latter distributed throughout the surface independently of the presence of L. monocytogenes. A fact that was especially evident in those biofilms in which cell clusters were present. Finally, a modified Gompertz equation was used to fit biofilms’ BAC and NEW dose-response data. Outcomes demonstrated that L. monocytogenes was less susceptible to BAC when co-cultured with P. aeruginosa or P. fluorescens whereas susceptibility to NEW was reduced in all three dual-species biofilms that can be attributable to both the mechanism of action of the biocide and the architectural features of each biofilm. Therefore, results herein provided can be used to optimize already existing and develop novel target-specific sanitation treatments based on mechanism of action of the biocide and the biofilms’ species composition and structure.
