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Bacteriophage typing of Vibrio ElTor
Abstract
Résumé On a développé un schéma de lysotypie deVibrio eltor. A l'aide de 5 types de bactériophages on a classé 3464 souches en 6 lysotypes et trouvé un type de bactériophage qui est toujours lytique pour les souches deV. eltor isolées de malades cholériques El Tor.
... It is based on the premise that bacteriophage contribute to the evolution V. cholerae via horizontal gene transfer, genomic recombination and predation. This phenomenon results in selection or clonal enrichment of certain strains of V. cholerae in a geographical location (Basu and Mukerjee, 1968). In the last 60 years, two phage typing schemes have been developed (Chattopadhay et al., 1993). ...
... In the last 60 years, two phage typing schemes have been developed (Chattopadhay et al., 1993). The first typing scheme developed by Basu and Mukerjee (1968) restricted strains into two clonal groups: phage type-2 and phage type-4, while the second typing scheme developed in 1993 provided an opportunity for better discrimination of strains (Mukerjee, 1978). As there are no phage type information about epidemic strains of V. cholera 01 in Nigeria, the present study was planned to determine the distribution and frequency of V. cholerae phage types responsible for cholera epidemics in Nigeria since 2007. ...
... However, the number of distinct phage types ranged from 4 to 8 strains across the studied sites with Ogun and Borno/Kano having the lowest and highest phage diversity of 2 and 5, respectively. Using the old phage type scheme of Basu and Mukerjee (1968), the observed disparity in percentages between T-2 and T4 phage types (55.8% vs. 44.2%; P > 0.05) was not significant ( Table 2) (Table 4). ...
Nigeria has been plagued with seasonal epidemics of cholera with high mortality impact since 2007. Data to understand the molecular epidemiology of strains for developing country-specific control measures are either not available or incomplete in most of the epidemic states. To bridge this information gap, this study determined the phage type profiles of some selected Vibrio cholerae 01 biotype El Tor strains involved in epidemic between 2007 and 2013 in nine states of the country. A total of 52 epidemic strains of V. cholerae from nine states: Abia, Bauchi, Borno, Kano, Gombe, Ilorin, Lagos, Ogun and Osun based on viability and positive serogrouping of 122 stock cultures were phage typed using both the old (two groups) and new (10 groups) typing schemes according to World health Organization (WHO) guidelines. Data were descriptively analyzed for variation and predominance of phage types using STATA 8.0. The proportions of strains belonging to the T2 and T4 phage types were 55.7 and 44.3%, respectively (P>0.05). With the new typing scheme, epidemic strains of phage types ranging from 4 to 8 were found per state. Further analysis revealed phage predominance in the following decreasing order: T-27>T-24>T-23. Other phage types seen were T-7, T-10, T-12, T-14, T-16 and T-17. Phage variation analysis further revealed involvement of strains from multiple phage types ≥3 during the 2010 cholera epidemics versus ≤2 in other cholera epidemics since 2007. Findings from this study indicate that multiple phage types of V. cholerae 01 biotype El Tor with the predominance of T-27 are common in Nigerian cholera epidemic situation since 2007.
... Phage typing at the National Institute of Cholera and Enteric Diseases (NICED), Kolkata, India includes the Basu S and Mukherjee S typing and new phage typing schemes. These two phage-typing schemes are specic for V. cholerae O1 and O139 and are being routinely used for the classication of strains at this institute [7,8]. Cholera can occur throughout the year, but maximum transmission is associated with high temperature, heavy rainfall, and ooding [9]. ...
... Phage typing was done by Basu S and Mukherjee S method and New Phage Typing method and susceptibility to phage IV and V for biotyping was done at NICED, Kolkata, West Bengal India [7,8]. ...
Cholera is an acute diarrheal disease caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. It is a Notiable Disease known to cause serious epidemics and pandemics in developing countries like India. To evaluate the proportion of Aim & objective: Vibrio cholerae positive stool samples along with Find out Biotypes, Serotypes and antimicrobial susceptibility patterns of V. Cholerae isolates. Material and Method: Total 873 stool samples were received and processed in the Bacteriology laboratory, Department of Microbiology, Medical College Baroda, during the period January 2022 to December 2022. Stool specimens were examined microscopically. Further processing, identication, Biotyping & Serotyping of the isolates was done by standard Biochemical tests. Antibiotic susceptibility testing was done & interpreted according to CLSI guidelines. Out of 873 stool samples 42(04.81% ) samples w Result: ere positive for Vibrio cholerae. Where is Classical(71.42%) Biotype & Serotype Ogawa was predominant. Maximum isolation was in rainy season (57.14%).The isolates were sensitive to Ceftriaxone (88.09%), Ciprooxacin (88.09%), Ampicillin(35.71%), Cotrimoxazol (35.71%), Doxycycline (28.57%). Classical Conclusions: Biotype and Serotype Ogawa was predominant. Antibiotic susceptibility pattern of V.cholera shows high sensitivity to Ceftriaxone & Ciprooxacin which should be the preferred agents for chemotherapy.
... Basu and Mukherjee initially proposed a phage typing scheme for V. cholerae O1 biotype ElTor in 1968, which was considered as a primary choice and a gold standard approach for differentiating V. cholerae biotype ElTor strains in the past. [17] Six phage types were identified by Basu and Mukherjee to characterize V. cholerae O1 biotype ElTor strains, among them phage type 2 and 4 are predominant whereas types 1, 3, 5, and 6 are not in circulation due to some unknown reason, investigation of which may require a separate study. A fundamental feature of the phage typing of V. cholerae was its usefulness in differentiating strains into several types as well as for differentiating classical and ElTor biotypes. ...
... Phage typing schemes for V. cholerae O1 and O139 were developed form NICED over the last few decades. [17][18][19][20] Apart from the importance of cholera bacteriophages to discriminate cholera strains, phages have been used as an alternative to antibiotic therapy to circumvent the burden of antibiotic resistance. [21,22] An earlier study has found that V. cholerae isolates from Kolkata, India are strongly correlated with resistance to some antibiotics such as streptomycin, tetracycline, and trimethoprim-sulfamethoxazole. ...
Background:
Cholera is a primordial disease caused by Vibrio cholerae which existed from centuries in different parts of the world and still shows its periodic, endemic and epidemic presence. Thousands of cholera cases are reported from different parts of India and the disease remains endemic throughout the year. At present, we do not have enough knowledge about the phenotypic nature of the circulating V. cholerae strains in this part of the world.
Objectives:
This study was carried out over a period of 6 years with the aim defer with the changes in the prevalence and distribution of biotypes, serotypes and phage types of V. cholerae clinical isolates from various endemic regions of the country to determine phenotypic characteristics of the circulating strains and also to predict the attributes of cholera strains responsible for causing significant outbreaks in future.
Materials and methods:
A total of 1882 V.cholerae O1 isolates from different cholera endemic areas of India were included in this study. V.cholerae strains which were identified as O1 biotype ElTor further analyzed for serotype and phage types using the standard methodologies. Polyvalent O1 and monospecific Inaba and Ogawa antisera were used for serotyping. A panel of five phages of Basu and Mukherjee phage typing scheme and five phages from the new phage typing scheme were used for phage typing analysis following standard methodology.
Results:
Maximum numbers of strains were isolated from cholera-endemic states like Gujarat and Maharashtra. All the isolates were confirmed as V. cholerae O1 biotype ElTor and majority of them were serotype Ogawa (93.2%). New phage typing scheme resulted in almost 100% typeable V. cholerae O1 strains included in this study and phage type 27 was the predominant type. Although 80% of the strains used in this study were sensitive to all the vibrio phages, S5 phage was found most efficient in lysing cholera strains indicating its broader host range.
Conclusion:
The current study identified phage type 27 as the most dominant type and serotype Ogawa was found continuous in circulation throughout the year which has caused recent cholera outbreaks in India during the past years. Phage sensitivity data propose an alternative cost-effective approach to prevent cholera outbreak by therapeutic uses of typing phages irrespective of origin or clonality of the strains.
... A total of 17 isolates of V. cholerae obtained during June 2010 to Dec.2012 were sent to the National Institute of Cholera and Enteric Diseases (NICED), Kolkata, for phage typing and serological confirmation. Phage typing was done by the Vibrio phage reference laboratory of NICED as per earlier published procedures [16,17]. ...
... Phage typing was done using Basu-Mukerjee and New phage typing schemes at NICED. All these isolates belonged to phage type T-2 as per Basu -Mukerjee scheme [16]. According to the new scheme for phage typing developed by NICED [17], 12 isolates were of phage type T-27, 2 were T-13 and 1 was T-26. ...
... Serological identification was carried out by slide agglutination using commercially available antisera against V. cholerae O1 (Ogawa and Inaba) and O139 serogroups. Phage typing was performed based on previously described schemes [14,15]. Susceptibility to antimicrobial agents was determined by the disk diffusion method and interpreted as recommended by Clinical and Laboratory Standards Institute (CLSI) with commercial antimicrobial disks, streptomycin (10 mg), tetracycline (30 mg), chloramphenicol (30 mg), sulfamethoxazole (25 mg), ciprofloxacin (5 mg) and trimethoprim (5.2 mg). ...
... This age distribution of cholera cases reflects that observed across many outbreaks occurring in Chandigarh between January 1999 and December 2007 [11]. The isolates fell predominantly into the single phage types T2 [14] or T27 [15] depending upon the scheme used for typing. The antibiotic sensitivity profiles of the isolates from Chandigarh showed that all isolates tested, except isolate 5202 that was only resistant to trimethoprim, were multi-drug resistant. ...
Background
Cholera infection continues to be a threat to global public health. The current cholera pandemic associated with Vibrio cholerae El Tor has now been ongoing for over half a century.
Methodology/Principal Findings
Thirty-eight V. cholerae El Tor isolates associated with a cholera outbreak in 2009 from the Chandigarh region of India were characterised by a combination of microbiology, molecular typing and whole-genome sequencing. The genomic analysis indicated that two clones of V. cholera circulated in the region and caused disease during this time. These clones fell into two distinct sub-clades that map independently onto wave 3 of the phylogenetic tree of seventh pandemic V. cholerae El Tor. Sequence analyses of the cholera toxin gene, the Vibrio seventh Pandemic Island II (VSPII) and SXT element correlated with this phylogenetic position of the two clades on the El Tor tree. The clade 2 isolates, characterized by a drug-resistant profile and the expression of a distinct cholera toxin, are closely related to the recent V. cholerae isolated elsewhere, including Haiti, but fell on a distinct branch of the tree, showing they were independent outbreaks. Multi-Locus Sequence Typing (MLST) distinguishes two sequence types among the 38 isolates, that did not correspond to the clades defined by whole-genome sequencing. Multi-Locus Variable-length tandem-nucleotide repeat Analysis (MLVA) identified 16 distinct clusters.
Conclusions/Significance
The use of whole-genome sequencing enabled the identification of two clones of V. cholerae that circulated during the 2009 Chandigarh outbreak. These clones harboured a similar structure of ICEVchHai1 but differed mainly in the structure of CTX phage and VSPII. The limited capacity of MLST and MLVA to discriminate between the clones that circulated in the 2009 Chandigarh outbreak highlights the value of whole-genome sequencing as a route to the identification of further genetic markers to subtype V. cholerae isolates.
... 2 Bacteriophages of V. cholerae (Vibriophages) V. cholerae is the host for a variety of bacteriophages, which are generally referred to as ''vibriophages''. These phages include temperate phages represented by kappa-type phage produced by most El Tor biotype strains, and virulent phages, e.g., Mukherjee's cholera phages (Basu and Mukerjee 1968) which were popularly used for phage typing of V. cholerae O1. The use of phage susceptibility as a method of strain differentiation has contributed greatly to the understanding of the epidemiology of cholera. ...
... The use of phage susceptibility as a method of strain differentiation has contributed greatly to the understanding of the epidemiology of cholera. A phage typing scheme for V. cholerae O1 biotype E1 Tor (Basu and Mukerjee 1968) was efficiently used to study the initial spread of the E1 Tor biotype of V. cholerae O1. Later, new phage typing schemes were developed for V. cholerae O1 (Chattopadhyay et al. 1993), andO139 (Chakrabarti et al. 2000), in which new lytic phages were used. ...
Understanding the genetic and ecological factors which support the periodic emergence of toxigenic Vibrio cholerae causing outbreaks of cholera in regions where the disease is endemic, is vital to develop preventive measures. Besides environmental factors which are not precisely defined, bacteriophages bacteriophages , and horizontally transmissible genetic elements genetic elements are known to have a significant role in the epidemiology and evolution of the pathogen. Cholera epidemics are also known to be self-limiting, and hence identifying natural factors which contribute to the collapse of epidemics may have important implications in controlling the disease. Phages have been shown to play a crucial role in modulating cholera epidemics, and enhance V. cholerae V. cholerae evolution through a bactericidal selection process which favors the emergence of new clones.
... Among several typing methods, phage typing is one of the most important and useful methods for the identification and differentiation of V. cholerae strains. A phage-typing scheme was developed by Basu & Mukerjee for V. cholerae O1 biotype El Tor [5] and later a new phage-typing scheme was developed for O1 [6]. Subsequently, a further phage-typing scheme specific for V. cholerae O139 was developed at the National Institute of Cholera and Enteric Diseases (NICED) [7]. ...
... Sixty-seven strains of O1 El Tor, 29 of V. cholerae O139, 23 non-O1/non-O139 and six O1 classical strains were included. V. cholerae O1 biotype El Tor strains MAK 757 (ATCC 51352) and N16961, V. cholerae O1 biotype classical strains CL-154 and O395 and V. cholerae O139 strain NPR-4 were used as controls [5,6,22,23]. All these strains were maintained in nutrient agar stabs and kept in the dark, at the Vibrio Phage Reference Laboratory, NICED. ...
This study attempted to examine the relatedness between RAPD-PCR, PFGE and VcA VNTR results with those of conventional phage typing of V. cholerae strains and to evaluate VcA VNTR as an indispensable molecular-typing tool that accomplishes the urgent need for effective epidemiological surveillance. All the O1 El Tor strains were predominantly clustered into phage type T27 with the new phage-typing scheme. Using RAPD-PCR, a total of 69 O1 El Tor strains were grouped under 16 different electrophoretic patterns. A total of 33 pulsotypes were identified in these strains by PFGE. VcA VNTR revealed high VcA polymorphism in all V. cholerae strains incorporated in this study. Our results underline the considerable potential of VcA VNTR analysis as a tool for molecular typing of V. cholerae.
... Inaba contributed 3.5%. Basu and Mukherjee methods of phage typing indicated that type 27 was a predominant phage-type of cholera in India, followed by type 26 [22,25,26]. This definitive long-term study suggests that cholera was endemic over larger areas of India than was previously suggested. ...
Presently, Cholera outbreaks account for 1.3 to 4.0 million cases and causes between 21,000 and 143,000 deaths worldwide. Cholera is preventable by proper sanitization and immunization however in many developing nations such as India, Cholera disease is endemic.
The surveillance system in India does not adequately capture the actual number of cases. Consequently, it is important to utilize limited public health resources correctly in India and other developing counties more effectively to reach vulnerable communities. Here, we analyse how studies make sense of Cholera transmission and spread in India from 1996-2015. Further, how a more sensitive surveillance system can contribute to cholera eradication by giving rise to outbreak preparedness.
... It is thought that in aquatic reservoirs, evolution of resistance and counter-resistance gives rise to cyclical patterns of increasing V. cholerae populations, followed by phage amplification and coincident bacterial decline, leading to phage decline and bacterial blooms once again (Figure 1a). These collective observations, alongside the use of phages to identify types of V. cholerae to address the clonality of cholera outbreaks (5) and renewed interests in harnessing phages for preventing cholera outbreaks (6), have fostered a long-standing interest in cholera-associated phages. This review focuses on one such lytic phage, International Centre for Diarrheal Disease Research, Bangladesh cholera phage 1 (ICP1), which has emerged as a persistent and pervasive phage shaping the evolution of epidemic V. cholerae ( Figure 1). ...
Bacteriophages or phages—viruses of bacteria—are abundant and considered to be highly diverse. Interestingly, a particular group of lytic Vibrio cholerae–specific phages (vibriophages) of the International Centre for Diarrheal Disease Research, Bangladesh cholera phage 1 (ICP1) lineage show high levels of genome conservation over large spans of time and geography, despite a constant coevolutionary arms race with their host. From a collection of 67 sequenced ICP1 isolates, mostly from clinical samples, we find these phages have mosaic genomes consisting of large, conserved modules disrupted by variable sequences that likely evolve mostly through mobile endonuclease-mediated recombination during coinfection. Several variable regions have been associated with adaptations against antiphage elements in V. cholerae; notably, this includes ICP1’s CRISPR-Cas system. The ongoing association of ICP1 and V. cholerae in cholera-endemic regions makes this system a rich source for discovery of novel defense and counterdefense strategies in bacteria-phage conflicts in nature.
Expected final online publication date for the Annual Review of Virology, Volume 8 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
... [2,3] Isolates obtained were sent for phage typing by conventional Basu Mukherjee and new phage typing as per procedures published earlier in authors reference laboratory NICED Kolkata India. [4,5] Vibrio cholerae isolates were obtained from 50 of the 1126 fecal specimens processed giving a positivity rate of 4.4% . ...
... Phage typing has been used to identify V. cholerae strains and has contributed greatly to understanding cholera epidemiology. In 1968, Basu and Mukerjee developed a typing scheme using five groups of phages, allowing them to successfully identify 3,464 strains from different epidemics between 1937 and 1966 [2]. Additional updated phage collection schemes [3,4]. ...
This review highlights recent findings on the evolutionary arms race between the causative agent of cholera Vibrio cholerae and virulent bacteriophages (phages) ICP1, ICP2, and ICP3 isolated from cholera patient stool samples. We discuss mechanisms of phage resistance such as a unique phage-inhibitory chromosomal island and mutations that affect phage receptor expression. We also discuss the molecular characterization of ICP1 and its unique CRISPR-Cas system, which it uses to combat the phage-inhibitory chromosomal island. The role of phages in the life cycle of V. cholerae has been increasingly recognized and investigated in the past decade. This article will review hypotheses as to how the predator-prey relationship may have an impact on infections within individuals and on the self-limiting nature of cholera epidemics. In addition, we put forth a strategy of using phages as an intervention to reduce household transmission of cholera within a community.
... Vibrio cholerae is host to various bacteriophages (vibriophages) including temperate phages (kappa-type phages) and virulent phages (Mukherjee's cholera phages). These phages were commonly used for V. cholerae O1 phage typing (Basu and Mukerjee, 1968). Later, virulent phages were used for the phage typing of V. cholerae O1 (Chattopadhyay et al., 1993) and O139 (Chakrabarti et al., 2000). ...
Bacteriophages are the most common entities on earth and represent a constant
challenge to bacterial populations. To fend off bacteriophage infection, bacteria
evolved immune systems to avert phage adsorption and block invader DNA entry.
They developed restriction–modification systems and mechanisms to abort infection
and interfere with virion assembly, as well as newly recognized clustered regularly
interspaced short palindromic repeats (CRISPR). In response to bacterial immune
systems, bacteriophages synchronously evolved resistance mechanisms, such as the
anti-CRISPR systems to counterattack bacterial CRISPR-cas systems, in a continuing
evolutionary arms race between virus and host. In turn, it is fundamental to the survival
of the bacterial cell to evolve a system to combat bacteriophage immune strategies.
... The number 0 is used to record evidence of lysis from without. The typical reaction patterns for a variety of phage can be found in the published literature, and Public Health Agencies and commercial companies still routinely use these methods for the subtyping of a range of bacteria, such as Salmonella enterica, 46,47 Escherichia coli O157 48,49 Shigella, 50 Vibrio cholerae, 51,52 Staphylococcus aureus, 45,53 Listeria monocytogenes, [54][55][56] and Bacillus spp. 50 ...
... The number 0 is used to record evidence of lysis from without. The typical reaction patterns for a variety of phage can be found in the published literature, and Public Health Agencies and commercial companies still routinely use these methods for the subtyping of a range of bacteria, such as Salmonella enteric, 46,47 Escherichia coli O157 48,49 Shigella, 50 Vibrio cholerae, 51,52 Staphylococcus aureus, 45,53 Listeria monocytogenes, [54][55][56] and Bacillus spp. 50,57,58 use of Phage typing These phage-typing sets have been successfully used in epidemiological studies to monitor changes in the predominant organism causing disease in a population and also the emergence of new dominant clones. ...
... One of the earlier studies on cholera phages was carried out by Nobechi in 1923 and has been summarized (Pollitzer et al., 1959). Subsequently, phage typing was done using Mukerjee's cholera phages (Basu and Mukerjee, 1968). The FK phages of Takeya et al. (1981) later were adopted to differentiate classical and El Tor biotypes. ...
Vibrio cholerae, the etiological agent of cholera, has been a scourge for centuries. Cholera remains a serious health threat for developing countries and has been responsible for millions of deaths globally over the past 200 years. Identification of V. cholerae has been accomplished using a variety of methods, ranging from phenotypic strategies to DNA based molecular typing and currently whole genomic approaches. This array of methods has been adopted in epidemiological investigations, either singly or in the aggregate, and more recently for evolutionary analyses of V. cholerae. Because the new technologies have been developed at an ever increasing pace, this review of the range of fingerprinting strategies, their relative advantages and limitations, and cholera case studies was undertaken. The task was challenging, considering the vast amount of the information available. To assist the study, key references representative of several areas of research are provided with the intent to provide readers with a comprehensive view of recent advances in the molecular epidemiology of V. cholerae. Suggestions for ways to obviate many of the current limitations of typing techniques are also provided. In summary, a comparative report has been prepared that includes the range from traditional typing to whole genomic strategies.
... Culture of specimens, identification, biochemical characterization, serotyping and antibiotic sensitivity of isolates were done as per standard technique.[2,3]Isolates obtained were sent for phage typing by conventional Basu Mukherjee and new phage typing as per procedures published earlier in authors reference laboratory NICED Kolkata India.[4,5]Vibrio cholerae isolates were obtained from 50 of the 1126 fecal specimens processed giving a positivity rate of 4.4% . ...
A retrospective analysis was done over a period of 3 years (January 2010- December 2012) in a tertiary care hospital, Pune, to note the changes in the prevalence and distribution of biotypes, serotypes, antibiotic susceptibility pattern and phage types of Vibrio cholerae isolates from clinical samples so as to be vigilant and curtail major outbreak in future. Vibrio cholerae isolates were obtained from 4.4% of the 1126 fecal specimens processed from cases of acute watery diarrhea. Majority of the isolates were identified as V. cholerae O1 biotype El Tor serotype Ogawa (98%); Phage 27 was the predominant type (77.5%). Majority
of the cases were encountered during the months June-August (68%). Antibiogram over a period of 3 years showed that isolates were consistently resistant to Ampicillin (90%) and Furazolidone (88%). Low level of resistance was seen with Norfl oxacin (8%), Gentamicin (8%) and Tetracycline (6%). All isolates were susceptible to Chloramphenicol.
... Although reports of the use of phage therapy in Western medicine are rare (9), phages have been used to differentiate bacterial species and strains (10)(11)(12)(13). Bacterium-phage specificity has been exploited for various bacterial typing schemes for decades; examples include Salmonella, Listeria, Vibrio cholerae, and Mycobacterium (14)(15)(16)(17). Phages have been used for developing many rapid diagnostic tools for bacterial detection, and it is also conceivable to design universal systems by modifying the specificities on the surface of the phage (18)(19)(20). ...
In order to better characterize the Bacillus anthracis typing phage AP50c, we designed a genetic screen to identify its bacterial receptor. Insertions of the transposon mariner or targeted deletions of the structural gene for the S-layer protein Sap and the sporulation genes spo0A, spo0B, and spo0F in B. anthracis Sterne resulted in phage resistance with concomitant defects in phage adsorption and infectivity. Electron microscopy of
bacteria incubated with AP50c revealed phage particles associated with the surface of bacilli of the Sterne strain but not
with the surfaces of Δsap, Δspo0A, Δspo0B, or Δspo0F mutants. The amount of Sap in the S layer of each of the spo0 mutant strains was substantially reduced compared to that of the parent strain, and incubation of AP50c with purified recombinant
Sap led to a substantial reduction in phage activity. Phylogenetic analysis based on whole-genome sequences of B. cereus sensu lato strains revealed several closely related B. cereus and B. thuringiensis strains that carry sap genes with very high similarities to the sap gene of B. anthracis. Complementation of the Δsap mutant in trans with the wild-type B. anthracis sap or the sap gene from either of two different B. cereus strains that are sensitive to AP50c infection restored phage sensitivity, and electron microscopy confirmed attachment of
phage particles to the surface of each of the complemented strains. Based on these data, we postulate that Sap is involved
in AP50c infectivity, most likely acting as the phage receptor, and that the spo0 genes may regulate synthesis of Sap and/or formation of the S layer.
... Details of other phages, strains and methods of culture and assay have been reported elsewhere (Siddiqui and Bhattacharyya, 1982). Lytic phage of the eltor typing series (Basu and Mukerjee, 1968) are prefixed with E to distinguish them from temperate phage; e.g., Group-I11 typing phage is designated E3. ...
The role of temperate phage p in determining the serology and eltor-lytic phage sensitivity in Vibrio cholerae was investigated. The only serological change found in six host strains was a change to roughness. This was accompanied by failure to adsorb several of the lytic phages. Various phage-sensitivity changes were induced by phage fl in two hosts at the post-adsorption level. In strain HP47, three types of progeny were obtained of which one was universally resistant to lytic phages. These untypable lysogens were culturally stable but gave rise to segregants of the rare phage-type 6 on single colony selection.
... Biotype determination involved the following tests: chicken erythrocyte agglutination, hemolysis of sheep erythrocytes, Voges–Proskauer reaction, sensitivity to polymyxin B, and susceptibility to Mukerjee classical (CL) phage IV and Mukerjee ET phage V (18). To complement the biotype characterization, polymerase chain reaction (PCR) assays targeted to detect tcpA (CL and ET variants) (19) and to determine the type of rstR gene encoding the phage transcriptional regulator were carried out using previously described methods (20). ...
Vibrio cholerae is an estuarine bacterium associated with a single peak of cholera (March�May) in coastal
villages of Bangladesh.For anunknownreason, however, cholera occurs in a unique dual peak (March�May and September�November) pattern in the city of Dhakathat is bordered by a heavily polluted freshwater river system and flood embankment. In August 2007, extreme flooding was accompanied by an unusually severe diarrhea outbreak in Dhaka that resulted in a record high illness. This study was aimed to understand the unusual outbreak and if it was related to the circulation of a new V. cholerae clone. Nineteen V. cholerae isolated during the peak of the 2007 outbreak were subjected to extensive phenotypic and molecular analyses, including multilocus genetic screening by polymerase chain reaction (PCR), sequence-typing of the ctxB gene, and pulsed-field gel electrophoresis (PFGE). Factors associated with the unusual incidence of cholera were determined and analysis of the disease severity was done. Overall, microbiological and molecular data confirmed that the hypervirulent V. cholerae was O1 biotype El Tor (ET) that possessed cholera toxin (CT) of the classical biotype. The PFGE (NotI) and dendrogram clustering confirmed that the strains were clonal and related to the pre-2007 variant ET from Dhaka and Matlab and resembled one of two distinct clones of the variant ETconfirmed to be present in the estuarine ecosystem of Bangladesh. Results of the analyses of both diarrheal case data for three consecutive years (2006-�2008) and regional droclimatology over three decades (1980�2009) clearly indicate that the pattern of cholera occurring in Dhaka, and not seen at other endemic sites, was associated with flood waters transmitting the infectious clone circulating via the fecal-oral route during and between the dual seasonal cholera peaks in Dhaka. Circular river systems and flood embankment likely facilitate transmission of infectious V. cholerae throughout the year that leads to both sudden and off-season outbreaks in the densely populated urban ecosystem of Dhaka. Clonal recycling of hybrid ElTor with increasing virulence in a changing climate and in a region with a growing urban population represents a serious public health concern for Bangladesh.
... The strains were biotyped by group IV classical phage [7] and group 5 El Tor phage [8] using procedures described previously [9]. For polymyxin B sensitivity, the test strains were inoculated in tryptic soy broth and incubated under shaking condition for 2 h. ...
This study reports the results of a molecular analysis of the CTX prophages in classical biotype strains of Vibrio cholerae O1 of clinical origin isolated between 1970 and 1979 in India. All strains were sensitive to group IV classical phage and polymyxin B but resistant to group 5 El Tor phage. These phenotypic traits are consistent to that exhibited by the classical biotype. PCR studies reconfirmed their biotype assignment and showed the presence of intact CTX prophages and the presence of the recently described toxin linked cryptic plasmid. Restriction fragment length polymorphism of rRNA genes and pulsed-field gel electrophoresis showed clonal diversity among the strains. The most notable observation was the finding that one strain (GP13) has three CTX prophages while another (GP147) has four CTX prophages. This is the first time heterogeneity is reported in the arrangement of the CTX prophages among classical strains of V. cholerae O1.
... During a cholera outbreak, it is often important to know quickly the serotype and biotype of the causative strain, and bacteriophages have proven invaluable in as-Ghosh /Nair /Sarkar Intervirology 2 certaining this. A phage-typing scheme was developed to differentiate V. cholerae O1 El Tor by Basu and Mukerjee [2] (1968) in Kolkata (previously called Calcutta). NICED is a WHO collaborating center for research and training in diarrheal diseases and is recognized as a vibriophage reference laboratory. ...
In countries where cholera is endemic, Vibrio cholerae O1 bacteriophages have been detected in sewage water. These have been used to serve not only as strain markers, but also for the typing of V. cholerae strains. Vibriophage N4 (ATCC 51352-B1) occupies a unique position in the new phage-typing scheme and can infect a larger number of V. cholerae O1 biotype El Tor strains. Here we characterized the complete genome sequence of this typing vibriophage.
The complete DNA sequence of the N4 genome was determined by using a shotgun sequencing approach.
Complete genome sequence explored that phage N4 is comprised of one circular, double-stranded chromosome of 38,497 bp with an overall GC content of 42.8%. A total of 47 open reading frames were identified and functions could be assigned to 30 of them. Further, a close relationship with another vibriophage, VP4, and the enterobacteriophage T7 could be established. DNA-DNA hybridization among V. cholerae O1 and O139 phages revealed homology among O1 vibriophages at their genomic level.
This study indicates two evolutionary distinctive branches of the possible phylogenetic origin of O1 and O139 vibriophages and provides an unveiled collection of information on viral gene products of typing vibriophages.
... Phage typing of V.cholerae isolates was done by Basu and Mukherjee method at the Phage typing center, NICED, Kolkata (4,5) . ...
Background : Diarrhoeal diseases are a leading cause of morbidity and mortality among children in developing countries requiring hospitalisation. AIDS and indiscriminate use of antibiotics have further worsen the condition. Objectives : To assess the etiological agents causing diarrhea with the aim to limit indiscriminate use of antimicrobial agents. Methods : A cross-sectional study was done involving children and adults (of all age groups) suffering from gastrointestinal infection attending the OPD or admitted to Guru Teg Bahadur Hospital. The study was analysed using chi-square test and crosstab chi-square test. Results : Of the 2534 stool samples processed, 23.2% were positive for pathogens. 4.6% were positive for Shigella species, 2.37% for Salmonella species and 1.5% for Escherichia coli (E.coli). Vibrio cholerae OI El Tor serotype Ogawa (82.55%) was more common than serotype Inaba (19.5%). Vibrio cholerae strains were generally resistant to all drugs except Ciprofloxacin, Gentamicin, and Cefotaxime. Multidrug resistant Shigella and Salmonella species was also an important observation made. However parasitic and viral (rota virus) associated diarrhea did not exceed the bacterial causes. Conclusions : New pathogens have emerged as causative organisms of diarrhoa. Indiscriminate use of antibiotics can lead to drug resistance necessitating monitoring of drug susceptibility and formulation of drug policy in hospitals.
... Mutants were phage typed with the four classical and five El Tor phages of Mukerjee (3,22), five lysogenic phages from Newman (23), and four Calcutta sewage phages from S. Bhattacharya. Roughs were identified by resistance to the smooth-specific classical VCII phage (24) and to the lysogenic Newman phages PVc 117, PVc 120 sm, and PVc 301 (personal observation). ...
Mutants of Vibrio cholerae was isolated on the basis of reduced ability to induce diarrhea in orally challenged infant mice. Nitrosoguanidine-treated clones were screened for low fluid accumulation ratios in individual mice, and presumptive mutants were confirmed in additional mouse tests. Mutants were examined for alterations in phage type, motility, toxin production, proteolytic activity, neuraminidase production, amylase production, morphology, growth requirements, carbohydrate fermentations, in vitro growth patterns, and cell surface alterations. The types of mutants found included several with previously recognized virulence-associated markers (rough, nonmotile, toxin deficient, protease deficient); several types with pleiotropic alterations (cell morphology, decreased extracellular products); and several with no previously recognized virulence-deficient phenotype (purine requiring, cell surface altered, rapid death in vitro, no defect found). Dose-response kinetics showed that most mutants could provoke diarrhea if given in 100-fold greater numbers than the dose used for screening. Recovery of viable organisms from the gut late in infection showed reduction of survival and/or multiplication capacity for the mutants, with variation in the degree of reduction for the different classes.
... Bacteriophage typing of Vibrio cholerae, the causative agent of human cholera, is widely accepted as a convenient and highly discriminating method of identifying strains for epidemiological studies. The international set of typing phages, namely group I to V eltor phages (Basu & Mukerjee, 1968), has certain limitations as most of the strains are restricted to only two phage types. In order to develop a new phage typing scheme for V. cholerae biotype E1 Tor, a total of 13 phages from environmental sources were isolated of which five were found to be useful for typing purposes. ...
Five bacteriophages have been isolated for phage typing of Vibrio cholerae biotype El Tor. The morphology of these phages has been studied by electron microscopy.
... Although these biotypes differ in some biochemical properties (Finkelstein, 1973), they can be distinguished most conveniently on the basis of their susceptibility to different phages (Mukherjee, 1978). A number of phage typing schemes have been proposed (Mukherjee, 1978; Newman & Eisenstark, 1964; Basu & Mukherjee, 1968), the most recent one with 14 phages (Lee & Furniss, 1981). Cholera phages thus have received considerable attention but most of the studies have focused on serological properties and morphology on the basis of electron microscopy. ...
Biophysical characteristics of Vibrio eltor phage e4, a key phage in the Vibrio cholerae typing scheme were studied. This icosahedral phage was found to contain 12 structural polypeptides with mol. wt. ranging from 25,000 to 120,000. One of these polypeptides of mol. wt. 50,000 accounted for most of the structural proteins present and was probably the major phage capsid protein. The phage genome comprised a single linear, double-stranded DNA molecule, 69.2 kbp in length (45.6 X 10(6) mol. wt.) as determined by electron microscopy and restriction fragment analyses. The G + C content was 34.6%. Electron microscopy data indicated that unlike the DNAs of other cholera phages, phage e4 DNA is not circularly permuted. Adsorption under normal conditions was biphasic with rate constants of 1.02 X 10(-9)/ml/min up to 60% adsorption and 3 X 10(-10)/ml/min thereafter. Intracellular phage multiplication was characterized by a latent period of 27 min. The burst size was approximately 100 phage particles per infected cell.
Purpose: A retrospective analysis was done to note changes in prevalence, distribution of biotypes, serotypes, antibiotic susceptibility patterns and phage types of Vibrio cholerae isolated in Mahatma Gandhi Institute of Medical Sciences, Sevagram over a period of 16 years. Methods: A total of 535 strains of V. cholerae were isolated from 10,406 stool samples and rectal swabs from January 1990 to December 2005. These comprised of serogroups O1 - 427 (79.89%), O139 - 86 (16.07%) and non O1, non O139 - 22 (4.11%). No classical V. cholerae was isolated. Results: Vibrio cholerae serogroup O1 serotype Ogawa was the predominant isolate till 1992. During 1993, serogroup O139 became the main isolate; however, it completely disappeared during 1995-1996 only to reappear in 1997. Serotype Inaba in our area was conspicuous by its absence with only two strains being isolated till June 1999, but during July-December 1999, 11 out of 15 V. cholerae O1 isolates were El Tor Inaba. T4 was the predominant phage type till 1990, T2 during 1991-1994 and T27 (as per the new scheme) thereafter. Resistance to tetracycline varied between 2 and 17% for V. cholerae O1. Conclusions: The paper reports on the changing epidemiological markers of V. cholerae isolated from a rural hospital over a period of 16 years.
Objectives
We have isolated a total of five newer cholera phages which are novel broad host range to incorporate with the existing phage typing schemes for an extended typing scheme.
Materials and Methods
These newly isolated phages were well characterized including the electron micrograph. A total of 300 Vibrio cholerae strains were isolated from the different endemic region in India were included in phage typing study.
Results
These phages were found different from the existing phages. Electron microscopic results showed that the phages belonged to myophage and podophage group. Characterization of the phages based on pH, temperature, and organic solvent sensitivity showed differences among the phages used in this study. All the strains of Vibrio O1 were typeable (100%) with the five set of cholera phages. Of these, 40% strains were clustered under Type-1.
Conclusion
The newer Vibrio phages are novel and broad host range and will be useful to incorporate with the existing phage typing system for more precisely discriminate the strains of Vibrio cholerae.
Objectives
Cholera is a major gastroenteric disease with reports on fluctuation and resistance. Hence, the objective is to determine the trend in seasonality, resistance pattern, prevalent biotypes, serotypes and phage types between 2004 and 2013 among Vibrio cholerae isolates.
Design
A retrospective cross-sectional study.
Settings
A single-centre study was carried out at a tertiary care hospital in a metropolitan city (Mumbai) of a developing country (India).
Methods
Records of stool specimen cultures of patients with suspected cholera from January 2004 to December 2013 were analysed. The organisms were identified as per standard protocol. Antimicrobial susceptibility testing was performed as per Clinical Laboratory Standard Institute. Biotyping, serotyping and phage typing were carried out. From the confirmed cases of cholera, demographic and laboratory details were noted. Descriptive analysis was used and the data were presented in the form of percentages.
Results
Vibrio cholerae was predominant in males and was isolated from 9.41% (439/4664) of stool specimens. Variability was found in terms of the gross appearance of stool specimens, seasonal trend and antibiotic resistance pattern. The antimicrobial susceptibility showed a waxing and waning pattern for most of the antibiotics (ampicillin, cefuroxime, chloramphenicol, tetracycline) tested, while for a few others the strains were either uniformly sensitive (gentamicin, norfloxacin) or resistant (trimethoprim-sulfamethoxazole, nalidixic acid). All isolates belonged to subgroup O1 and biotype El Tor. The most common serotype was Ogawa. The predominant phage type was T2 (old scheme) and T27 (new scheme).
Conclusions
The predominant biotype, serotype and phage type were El Tor, Ogawa and T27 phage, respectively. The changing trends in antimicrobial resistance pattern over the years necessitate continued epidemiological and microbiological surveillance of the disease.
The first vibrio phages were identified by d’Herelle in 1926, and by the 1950s several distinct types of bacteriophage acting on V. cholerae had been described. These studies of cholera bacteriophages have been reviewed by Pollitzer.1 Most early studies were directed towards the use of cholera phages for treatment or prophylaxis rather than strain discrimination. Interest in cholera phages revived with the spread of the seventh pandemic and the appearance in the 1960s of the El Tor biotype, and has proceeded along two distinct lines—the development of phage-typing schemes using lytic phages and classification using lysogeny.
Our paper focuses on the characteristic of mammalian and bacterial viruses in aquatic environments. We described their role and occurrence in different types of environmental water. It is known that the role of viruses present in a water environment can be negative or positive. A negative role is connected with pathogenic viruses and positive with bacteriophages. Pathogenic viruses can cause diseases, whereas bacteriophages in water environment are an important component of the microbial loop in terms of their potential roles in regulating microbial mortality, production, community structure, and biochemical cycling.
La especificidad entre bacteriófagos y bacterias es una característica utilizada exitosamente para la detección de varias especies microbianas, Por este motivo, la detección de vibriófagos es una herramienta útil de investigación y podría ser un método rápido y conveniente de diagnóstico de Vibrio cholerae. El objetivo de este estudio fue detectar vibriófagos en muestras de aguas marinas someras y determinar las características morfológicas de estos vibriófagos. Se determinó la cinética de crecimiento de una cepa de Vibrio cholerae serotipo Inaba. Se analizaron cualitativa y cuantitativamente muestras tomadas de cinco puntos de un sector adyacente a la playa La Chira y de las desembocaduras del río Rímac y río Chillón, usándose distintos inóculos y varios periodos de incubación. Los bacteriófagos fueron concentrados y teñidos para el estudio morfológico por microscopía electrónica de transmisión. Los resultados obtenidos indican que la detección de vibriófagos podría ser una herramienta importante como indicador de la presencia de Vibrio cholerae.
A Vibrio cholerae O1 phage-typing scheme, developed in the USSR, has been used to type 120 strains of V. cholerae O1 isolated in Africa and Asia, and 56 non-O1 V. cholerae isolated in England and Wales from infections contracted abroad. 90.9% of V. cholerae O1 were typable. Phage type 13 predominated among African strains whereas types 11 and 15 were more common among strains from Asia. Only 14.3% of non-O1 V. cholerae reacted with the phages.
Phage N4 is one of the five newly isolated phages used in a new phage typing scheme for Vibrio cholerae O1 biovar EITor strains and belongs to the Podoviridae family. Electron microscopic studies showed that the phage N4 has a DNA of 40.4 ± 0.1 kb. A partial denaturation map of the N4 DNA has been constructed. It has been shown with the help of this partial denaturation map that phage N4 genome is nonpermuted. Circularization of the phage genome on treatment with exonuclease III, followed by incubation in 50% formamide, indicates a terminal redundancy.Key words: vibriophage N4, DNA, Vibrio cholerae, denaturation mapping.
The bacteriophage VP3 is used in a phage-biotyping scheme as one of the typing phages of Vibrio
cholerae O1 biotype El Tor strains. Here, we have sequenced and analyzed its genome. The genome consists of 39,481 bp with an overall G + C content of 42.6 %. Fifty-two open reading frames (ORFs) were predicted. Within the genome, 17 highly conserved phage promoters and 6 rho-independent terminators were predicted. When assessed with Rluc as a reporter gene, 12 of 16 cloned VP3 promoters showed activity in the host strain V.
cholerae biotype El Tor. Based on the temporal expression pattern detected using reverse transcription PCR (RT-PCR), VP3 ORFs can be classed into four groups, arranged according to their order in the VP3 genome. Terminators T1 and T6 are presumed to work efficiently. Sequencing of the typing phage VP3 of V.
cholerae reveals its evolutionary subdivisions from the members of T7-like phages of Escherichia
coli. Knowledge of VP3 expands the known host range of T7-like phages and will promote understanding the different infection mechanisms used by members of this genus.
Cholera is a disease of bacterial origin. It is not only important to recognize the disease clinically, but also to attempt as complete an identification of the causative organism as possible using various epidemiological typing procedures. This chapter explains the practical procedures currently available for the characterization, as well as a working background of the relevant theoretical knowledge. V. cholera is asporogenous, single curved or rigid rod with a single polar flagellum. It is indophenols oxidase positive and produces acid without gas from glucose. The aim of all typing systems is to identify strains within a species with a degree of precision that makes it safe to assume that all the isolates from an epidemic are truly identical and have therefore originated from a single parent strain. Of the three methods of typing V. cholera—serotyping, phage-typing and bacteriocin biotyping—serological typing was the earliest to be developed.
The disease cholera has persisted in Asia since time immemorial. Almost all the pandemic phases of cholera had its origin
from the Indian subcontinent. Historically, waves of cholera have wiped many million lives in this region mainly due to the
general insanitary conditions and poor management of the disease. All the three cholera causing vibrios namely classical,
El Tor, and the O139 have emerged from Asia at different times and one was replaced by the other by overcoming the acquired
immunity. Antimicrobial resistance was not a big problem in the early 1960s as its use was very limited. With the use of third-generation
drugs, Vibrio cholerae has acquired many resistance mechanisms over the passage of time and also due to prevailing antibiotic pressure. With its
biotypes/serotypes there are considerable variations at the genetic level and many clones of V. cholerae have been detected. Recently, the hybrid strain of El Tor has spread in many Asian countries causing several cholera outbreaks.
However, the importance of such genetic changes was not fully strengthened in epidemiological perspective. The perspectives
of cholera vaccines have shown to be encouraging in many recent vaccine trials in Asia. Traditional medicine has lost its
glory as it lacks the scientific evidence in curing infectious diseases. Some of the herbal formulations are now reconsidered
for extensive research. The control measures for preventing cholera are yet to gain momentum in many Asian countries, as it
involves coordination of government and the public with adequate funds to revamp the water supply and waste disposal systems.
On the other hand, the clinical management of cholera and other diarrheal diseases are largely under the control in Asia.
KeywordsEndemic cholera-Epidemics-Antimicrobial resistance-Sanitation-Molecular typing-Vaccines
Thirty-three cholera phages were studied by electron microscopy. Phages were tailed, had icosahedral heads and belonged to three families and seven morphological types, the Myoviridae (types X29, kappa and II), Styloviridae (type IV), and Podoviridae (types I, III and 4996). Types P2, III and IV closely resembled coliphages P2, T7 and T5, respectively. Certain phages produced abnormal particles, including irregular smooth polyheads, mottled and «petite heads and segmented and non-segmented polysheaths. The typing sets of Mukerjee (biovar cholerae) and Basu and Mukerjee (biovar eltor) should be used with caution, since some lysates contain several phages or because the original phage may have been replaced by a contaminant. Two other typing sets are incomplete. The Lee and Furniss set is recommended for phage typing of V. cholerae.RésuméTrente-trois phages de Vibrio cholerae ont été examinés au microscope électronique. Tous les phages ont une tête icosaédrique et une queue. Ils appartiennent aux trois familles et sept types morphologiques suivants: Myoviridae (types X29, kappa et II). Styloviridae (type IV) et Podoviridae (types I, III et 4996). Les types X29, III et IV ressemblent étroitement aux coliphages respectifs, P2, T7 et T5. Certains phages produisent des particules anormales, comprenant des polytêtes irrégulières lisses, des têtes tachetées ou «petites et des polymanchons segmentés ou non segmentés. Les bactériophages des schémas de lysotypie de Mukerjee (biovar cholerae) et de Basu et Mukerjee (biovar eltor) sont à utiliser avec prudence, puisque certains lysats contiennent plusieurs phages ou puisque le phage original peut avoir été remplacé par un contaminant. Deux autres jeux de phages sont incomplets. Le jeu de Lee et Furniss est recommandé pour la lysotypie de V. cholerae.
Cholera has been a prevalent disease worldwide since the early 19th century. Vibrio cholerae O1 and O139 are the two serogroups that have been mainly implicated in causing cholera. This study reports the results of biotyping, serotyping and phage typing of V. cholerae O1 and O139 (1998-2007) strains received from different parts of India for the identification of the trends in the occurrence and spread of cholera in the country. However, there has been a notable steep decline in the occurrence of V. cholerae O139 strains over the past few years resulting in no strain of V. cholerae O139 being received from any part of India in 2007 and 2008. Of the total strains received, 79.1% were serotyped as Ogawa and the remaining 20.9% were found to be Inaba, which indicates that Ogawa was the predominant serotype. Almost 100% typeability was observed with the new scheme of V. cholerae O1, with type 27 being the dominant phage type and V. cholerae O139 strains were clustered into the predominant phage type T-1. From the phage typing and serotyping results, it can be concluded that V. cholerae O1 (T-27) and O139 (T-1) strains circulate throughout the country at any given time.
The scenario of cholera that existed previously changed in 1992 and 1993 with the emergence of toxigenic Vibrio cholerae O139 in India. The genesis of the new serogroup formed the impetus to search for O139 phages in and around the country. A total of five newly isolated phages lytic to V. cholerae O139 strains were used for the development of this phage typing scheme. These phages differed from each other and also differed from the existing O1 phages in their lytic patterns, morphologies, restriction endonuclease digestion profiles, and immunological criteria. With this scheme, 500 V. cholerae O139 strains were evaluated for their phage types, and almost all strains were found to be typeable. The strains clustered into 10 different phage types, of which type 1 (38.2%) was the dominant type, followed by type 2 (22.4%) and type 3 (18%). Additionally, a comparative study of phage types in 1993 and 1994 versus those from 1996 to 1998 for O139 strains showed a higher percentage of phage type 1 (40.5%), followed by type 3 (18.8%) during the period between 1993 and 1994, whereas phage type 2 (32. 1%) was the next major type during the period from 1996 to 1998. This scheme comprising five newly isolated phages would be another useful tool in the study of the epidemiology of cholera caused by V. cholerae O139.
Cholera is endemic in Chandigarh and its surrounding areas. This retrospective study was undertaken over a period of nine years (January 1999-December 2007) from a tertiary care hospital in north India to understand the changing epidemiology aspects and antibiotic resistance patterns in Vibrio cholerae isolates.
A total of 277 isolates of V. cholerae were included in the study. V. cholerae was identified by standard microbiological procedures. Antibiotic sensitivity testing was performed by disc diffusion method and isolates phage typed.
All the isolates were identified as V. cholerae O1 biotype El Tor serotype Ogawa; phage 27 was the predominant type. Men were more commonly affected with maximum number in the age group 0-5 yr. Majority of the isolates were resistant to furazolidone but sensitive to gentamicin and cefotaxime. Resistance pattern to amoxycillin was variable. Three isolates were found to be resistant to ciprofloxacin. All the patients presented during June-October coinciding with the monsoon season and a majority were from suburbs.
The emergence of resistance amongst V. cholerae especially towards ciprofloxacin may significantly influence the control strategies in future outbreaks. Phage 27 remained the predominant type in all the years. Continuous surveillance with regard to drug resistance, early detection and a strong regional commitment may help contain the disease.
Salmonella weltevreden has been found to be one of the commonest Salmonella serotypes isolated from diverse sources in India and has also been isolated in a number of other countries. A phage typing scheme was developed for this serotype using a set of six typing phages. These phages had been selected out of 146 phage strains isolated and purified from stool samples of man, laboratory animals and other animals, sewage and surface water sources, and the lytic mutants of temperate phages from S. weltevreden.
The phage typing scheme was applied systematically to type the 946 strains from India isolated during 1958–1974 and 148 strains originating from Australia, Burma, England, Gan Island, Holland, Hong Kong, Malaysia, New Zealand, Papua New Guinea, The Philippines, Thailand, The United States and Vietnam during 1953–1971. The scheme was particularly studied to evaluate its utility in mapping the epidemiologically related strains from various sources.
The S. weltevreden strains could be classified into ten phage types. Phage types 2 and 7 were found exclusively amongst Indian strains, type 6 from Vietnam and type 8 from Burma, Thailand and Vietnam. Phage types were found to be stable and consistent with the independent epidemiological data available.
The epidemiological value of phage typing of El Tor vibrios in West Africa was assessed by testing 211 representative strains from all outbreaks of the cholera epidemic in Togo (1970-73) with the prophage typing method of Nicolle et al. and the lytic El Tor phages of Basu & Mukerjee. Prophage typing proved to be of limited epidemiological value in Togo since 203 of the 211 strains tested belonged to the same phage type-namely, type 2 of Nicolle et al., which corresponds to the Celebes type of Takeya. Six strains belonged to type 1, 1 strain to type 4, and 1 strain was untypable.Tested by the lytic El Tor phages, 175 strains were found to belong to type 4 of Basu & Mukerjee, 35 strains to type 1, and 1 strain was untypable. All but two strains of type 1 were isolated from 3 outbreaks in which this phage type was found almost exclusively. The results are in good agreement with epidemiological data collected during the epidemic. El Tor phage V reacted with a specificity of over 99% when tested against 601 strains of El Tor and NCV vibrios from Togo and may be recommended for the rapid identification of El Tor vibrios.
The ability of motile strains of the Ogawa and Inaba serotypes of classical Vibrio cholerae and of the El Tor biotypes to kill suckling mice after oral challenge with 10-8 colony-forming units (representing at least 100 to 1,000 minimal lethal doses) was compared to that of nonmotile derivatives of the same strains. Loss of motility, in each case, resulted in a marked reduction in virulence. The mortality (at 36 h) caused by 10 of the 13 nonmotile strains was 32% or less. whereas the motile wild-type strains resulted in nearly 100% deaths. The reduced virulence of the nonmotile strains was associated with reduced capacity to adsorb to the surface of segments of mouse intestine. The mutants were tested for alterations in enterotoxin production and surface properties. The results suggest that motility may contribute to virulence by increasing the chance for association of the vibrios with the intestinal mucosa.
Transfer RNAs were isolated from uninfected and phage e4-infected Vibrio eltor Mak 757 cells. These tRNAs were then aminoacylated with 3H-labeled amino acids and hybridized to DNA isolated from phage e4. Significant hybridization was observed only with tRNA isolated from phage e4-infected cells. Restriction enzyme digestion of phage e4 DNA followed by Southern blot using [32P]tRNA from infected cells revealed that tRNA genes were contained in a 3.4-kb Kpnl fragment. The tRNA genes were located on the physical map of the phage genome 19 kb from one of the termini.
91 strains of Vibrio cholerae O1, isolated in Bangladesh in January 1986, were examined for their biological behaviour and sensitivity to 6 antimicrobial
agents. Biotyping indicated that 60 of the isolates belonged to the classical biotype and 31 to the El Tor biotype. 21 El
Tor strains revealed β-haemolysis on blood agar plates, but only 8 showed complete haemolysis in broth. Serotyping indicated
79 Ogawa, 10 Inaba, and 2 Hikojima. Phage typing showed that all classical vibrios belonged to Mukerjee#x0027;s phage type
1. El Tor vibrios were classified into 4 groups: one strain each in type 1 and type 5, 19 in type 4, and 10 in an untypable
group. Prophage typing of El Tor vibrios identified 14 strains of Ubol type, 16 of cured Celebes type, and one of original
Celebes type. No strain was resistant to tetracycline, minocycline, chloramphenicol, streptomycin, amoxicillin or nalidixic
acid. The classical vibrios differed from those isolated before 1973 in toxin production pattern.
The effect of varying levels of extracellular protease production on the bacteriophage type of Vibrio cholerae 1621 serotype 01, biotype E1 Tor, has been investigated. It has been shown that the production of high levels of exoprotease can alter the apparent type of the strain by rendering it insensitive to infection by a number of bacteriophages. Prevention of a productive infection appears to be due to altered surface characteristics rather than to specific damage to the bacteriophages. Such altered surface characteristics may be due to auto-digestion. The importance of this observation to epidemiological studies of V. cholerae is noted and discussed.
Thesis (Ph. D.)--Kansas State University, 1962.