Incidence and toxigenicity of Vibrio cholerae in a freshwater lake during the epidemic of cholera caused by serogroup O139 Bengal in Calcutta, India

Ghosh, A

doi:10.1016/0168-6496(94)90112-0

Cited by 4 publications

(4 citation statements)

References 19 publications

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“…Non-O1, non-O139 V. cholerae was isolated from all three environmental sites. This is similar to other studies which have demonstrated the ubiquitous nature of these organisms and led to the hypothesis that they, in some way, have a survival advantage over V. cholerae O1 and O139 [12][13][14][15][16]. The reservoirs…”

Section: Discussionsupporting

confidence: 84%

“…It is not clear if this led to the dissemination of these strains into the environment leading to their detection in this study or indeed if the opposite was true and the appearance of these serotypes in the environment led to increased clinical disease. It has been speculated that the introduction of toxigenic strains of V. cholerae O1 and O139 strains into the environment leads to an increase in toxin production amongst the other aquatic serotypes by means of genetic exchange [14]. In this survey none of the non-O1, non-O139 isolates of V. cholerae contained the ctx operon as determined by PCR suggesting that this has not occurred in Vellore.…”

Section: Discussionmentioning

confidence: 68%

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The prevalence of Vibrio spp. in drinking water and environmental samples in Vellore South India

Thomson

Balaji

et al. 1998

Epidemiol. Infect.

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The prevalence of Vibrio cholerae in drinking water, lakes and sewage outfalls during July and August 1996 in Vellore, India was determined. Drinking water samples were collected on single occasions from 12 sites in different geographic areas of the town where cholera had been reported. Samples of water, plankton and sediment were collected from fixed sites at three lakes on three occasions separated by at least 3 days during the course of the study. Samples from open sewers were taken from two representative sites in four areas of the town. Bacteria isolated from samples were identified by standard biochemical tests and isolated strains of V. cholerae tested for their ability to agglutinate O1 and O139 antisera. Water samples from lakes were also tested for the presence of V. cholerae O1 and O139 by fluorescent antibody staining. Non-O1, non-O139 strains of V. cholerae were detected in 41% of drinking water samples and 100% of water, sediment and plankton samples from the test lakes. Eighty-seven per cent of open sewers sampled contained viable non-O1, non-O139 V. cholerae. Fluorescent antibody staining gave positive results for V. cholerae O1 and O139 for all water samples from the three lake sites. Strains of Aeromonas spp. were isolated from 58% of drinking water samples and from 66% of sediment, 77% of plankton and 55% of water samples from lakes. All open sewers sampled contained Aeromonas spp. PCR amplification employing specific primers demonstrated that none of the non-agglutinating V. cholerae isolates contained the ctx operon. The non-O1, non-O139 V. cholerae isolates showed different patterns of antibiotic resistance to ampicillin, ciprofloxacin, chloramphenicol, tetracycline and trimethoprim.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 68%

The prevalence of Vibrio spp. in drinking water and environmental samples in Vellore South India

Thomson

Balaji

et al. 1998

Epidemiol. Infect.

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“…A recent demonstration of the presence of CT-positive but TCP-negative non-O1, non-O139 strains in the environment (13) supports this assumption. It is also interesting that a previous study in India reported an increased incidence of toxigenicity among freshwater isolates of V. cholerae non-O1, non-O139 strains during a cholera outbreak caused by V. chol- erae O139 (12). This emphasizes the importance of further studies to understand the propagation of CTX⌽ and its role in the ecology of V. cholerae.…”

Section: Resultsmentioning

confidence: 92%

Analysis of Clinical and Environmental Strains of Nontoxigenic Vibrio cholerae for Susceptibility to CTXΦ: Molecular Basis for Origination of New Strains with Epidemic Potential

et al. 1998

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Toxigenic Vibrio cholerae strains are lysogens of CTXΦ, a filamentous phage which encodes cholera toxin. The receptor for CTXΦ for invading V. cholerae cells is the toxin-coregulated pilus (TCP), the genes for which reside in a larger genetic element, the TCP pathogenicity island. We analyzed 146 CTX-negative strains of V. cholerae O1 or non-O1 isolated from patients or surface waters in five different countries for the presence of the TCP pathogenicity island, the regulatory genetoxR, and the CTXΦ attachment sequence attRS, as well as for susceptibility of the strains to CTXΦ, to investigate the molecular basis for the emergence of new clones of toxigenicV. cholerae. DNA probe or PCR assays for tcpA,tcpI, acfB, toxR, andattRS revealed that 6.85% of the strains, all of which belonged to the O1 serogroup, carried the TCP pathogenicity island,toxR, and multiple copies of attRS, whereas the remaining 93.15% of the strains were negative for TCP but positive for either one or both or neither of toxR andattRS. An analysis of the strains for susceptibility to CTXΦ, using a genetically marked derivative of the phage CTX-KmΦ, showed that all TCP-positive CTX-negative strains and 1 of 136 TCP-negative strains were infected by the phage either in vitro or in the intestines of infant mice. The phage genome integrated into the chromosome of infected V. cholerae O1 cells forming stable lysogens. Comparative analysis of rRNA gene restriction patterns revealed that the lysogens derived from nontoxigenic progenitors were either closely related to or distinctly different from previously described clones of toxigenic V. cholerae. To our knowledge, this is the first demonstration of lysogenic conversion of naturally occurring nontoxigenic V. cholerae strains by CTXΦ. The results of this study further indicated that strains belonging to the O1 serogroup of V. cholerae are more likely to possess the TCP pathogenicity island and hence to be infected by CTXΦ, leading to the origination of potential new epidemic clones.

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“…Some microbes also synthesize a long-lived super agonist of guanylin. For example the LT (heat labile toxin)/CT (cholera toxin) secreted by E. coli like ETEC (Enterotoxicogenic E. coli ) 30 and V. cholerae O1, O139, 59 , 60 that interact with the monosialotetrahexosyl ganglioside 1 (GM1) gangliosides and increase adenosine monophosphate (AMP) levels, decrease sodium–potassium and chlorine absorption and aid in the etiology of diarrhoeae. 8 , 61 , 62 What is interesting here is the question of whether changes like these, that help a microbe survive as a pathogen in the short term, help it become a commensal eventually in the long run.…”

Section: Mimicking the Host Physiology Aids Colonizationmentioning

confidence: 99%

Appraisal of Microbial Evolution to Commensalism and Pathogenicity in Humans

Ghosh¹

2013

Clin Med Insights Gastroenterol

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The human body is host to a number of microbes occurring in various forms of host-microbe associations, such as commensals, mutualists, pathogens and opportunistic symbionts. While this association with microbes in certain cases is beneficial to the host, in many other cases it seems to offer no evident benefit or motive. The emergence and re-emergence of newer varieties of infectious diseases with causative agents being strains that were once living in the human system makes it necessary to study the environment and the dynamics under which this host microbe relationship thrives. The present discussion examines this interaction while tracing the origins of this association, and attempts to hypothesize a possible framework of selective pressures that could have lead microbes to inhabit mammalian host systems.

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Incidence and toxigenicity of Vibrio cholerae in a freshwater lake during the epidemic of cholera caused by serogroup O139 Bengal in Calcutta, India

Cited by 4 publications

References 19 publications

The prevalence of Vibrio spp. in drinking water and environmental samples in Vellore South India

The prevalence of Vibrio spp. in drinking water and environmental samples in Vellore South India

Analysis of Clinical and Environmental Strains of Nontoxigenic Vibrio cholerae for Susceptibility to CTXΦ: Molecular Basis for Origination of New Strains with Epidemic Potential

Appraisal of Microbial Evolution to Commensalism and Pathogenicity in Humans

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