Studies on the growth of <i>Vibrio cholerae</i> biotype eltor and biotype classical in foods

Kolvin, Jennifer L.; Roberts, Diane

doi:10.1017/s0022172400070777

Cited by 63 publications

(34 citation statements)

References 9 publications

(9 reference statements)

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“…Contamination of drinking water was lower than that of foods but like other studies (10) it increased during the rainy season. It was observed that foods eaten after 4 (12). Similar results have been obtained in The Gambia where supplementary foods given to children were heavily contaminated with bacteria, particularly if they were allowed to stand after being prepared (13)(14).…”

Section: Discussionsupporting

confidence: 75%

Bacterial contamination of weaning foods and drinking water in rural Bangladesh

et al. 1990

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SUMMARYThe aim of this study was to determine what weaning foods and food preparation practices expose children to a high risk of diarrhoeal disease through exposure to a contaminated diet. Bacterial contamination of 897 food and 896 drinking water samples was assessed in a water and sanitation intervention project.The geometric mean of faecal coliforms per g or ml was 7-5 x 103 in left-over rice, 1-4 x 102 in other types of boiled rice, 2-5 x 102 in milk, 4-8 in household drinking water, and 3-5 in bread. Multiplication of faecal coliforms occurred when there was a delay of more than 4 h between preparation and consumption of food. All samples were more contaminated in the rainy than in the dry season. Strategies to reduce contamination should therefore focus on 'wet' foods, early consumption after preparation, and re-heating of left-over foods. Understanding the reasons for the faulty practices is also essential to the formulation of effective measures.

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Section: Discussionsupporting

confidence: 75%

Bacterial contamination of weaning foods and drinking water in rural Bangladesh

et al. 1990

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“…A negative association between waterborne transmission and desiccation resistance does exist among Shigella sp. [6] and between el tor and classical V. cholerae [26,301,302]. These associations, however, are also consistent with the cultural vectors hypothesis, because contact transmission, desiccation resistance, and benignness should favour each other evolutionarily.…”

Section: The Overall Trend and Alternative Hypothesessupporting

confidence: 71%

Waterborne transmission and the evolution of virulence among gastrointestinal bacteria

Ewald

1991

Epidemiol. Infect.

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SUMMARYDiarrhoeal diseases are primary contributors to millions of deaths annually. Yet, little is known about the evolutionary reasons for the differences in virulence among gastrointestinal pathogens. Applying the comparative, cost/benefit approach of evolutionary biology this paper proposes that waterborne transmission should favour evolution towards high virulence. This hypothesis is supported by a cross-specific test, which shows that waterborne transmission is strongly correlated with the virulence of bacterial gastrointestinal pathogens of humans. Alternative explanations of this correlation are not supported by available data. These findings bear on public health policy because they draw attention to a previously unrecognized long-range benefit gained from purification of water supplies: diarrhoeal pathogens may evolve to lower levels of virulence.

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“…In spite of the fact that clinical symptoms caused by V. cholerae El are less severe than those caused by V. cholerae Cl , V. cholerae El appears to have outcompeted V. cholerae Cl during the current pandemic (26). It has been proposed that this occurred because of the increased environmental fitness of V. cholerae El (23), the differential susceptibility to lytic phages between the biotypes (47), or the ability of V. cholerae El to more productively utilize carbohydrates such as chitin, which V. cholerae metabolizes when associated with zooplankton in the environment (33,54).…”

Section: Discussionmentioning

confidence: 94%

Distinct Sensory Pathways in Vibrio cholerae El Tor and Classical Biotypes Modulate Cyclic Dimeric GMP Levels To Control Biofilm Formation

Hammer

Bassler

2009

J Bacteriol

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Quorum sensing (QS), or cell-cell communication in bacteria, is achieved through the production and subsequent response to the accumulation of extracellular signal molecules called autoinducers (AIs). To identify AI-regulated target genes in Vibrio cholerae El Tor (V. cholerae El ), the strain responsible for the current cholera pandemic, luciferase expression was assayed in an AI ؊ strain carrying a random lux transcriptional reporter library in the presence and absence of exogenously added AIs. Twenty-three genes were identified and shown to require the QS transcription factor, HapR, for their regulation. Several of the QS-dependent target genes, annotated as encoding hypothetical proteins, in fact encode HD-GYP proteins, phosphodiesterases that degrade the intracellular second messenger cyclic dimeric GMP (c-di-GMP), which is important for controlling biofilm formation. Indeed, overexpression of a representative QS-activated HD-GYP protein in V. cholerae El reduced the intracellular concentration of c-di-GMP, which in turn decreased exopolysaccharide production and biofilm formation. The V. cholerae classical biotype (V. cholerae Cl ), which caused previous cholera pandemics and is HapR ؊ , controls c-di-GMP levels and biofilm formation by the VieA signaling pathway. We show that the VieA pathway is dispensable for biofilm formation in V. cholerae El but that restoring HapR in V. cholerae Cl reestablishes QS-dependent repression of exopolysaccharide production. Thus, different pandemic strains of V. cholerae modulate c-di-GMP levels and control biofilm formation in response to distinct sensory pathways.Over the past century, pandemic outbreaks of the diarrheal disease cholera have been caused by only two Vibrio cholerae biotypes (11). The classical biotype (V. cholerae Cl ) was responsible for the sixth pandemic, which lasted from 1899 to 1923. The etiological agent of the current seventh pandemic that began in 1961 is V. cholerae El Tor (V. cholerae El ). V. cholerae is an aquatic organism and its life cycle includes only transient colonization of the human small intestine. In humans, virulence factors elicit diarrhea, which is often fatal to the host but is also critical for efficiently transmitting the bacterium back into the environment (12). In marine habitats, V. cholerae is often found attached to other organisms in microbial communities called biofilms (19,20). Ingestion of contaminated water or food is the mode of transmission into the human gastrointestinal tract. Understanding the mechanisms used by these two V. cholerae biotypes to control virulence factor production and biofilm formation, as well as understanding the factors responsible for the emergence of V. cholerae El as the dominant biotype, have been the focus of active research for decades.A bacterial cell-cell communication process called quorum sensing (QS) is used to control virulence and biofilm formation in V. cholerae El (14,34,56). QS is accomplished through the synthesis, release, and subsequent detection of signaling molecules cal...

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Studies on the growth of Vibrio cholerae biotype eltor and biotype classical in foods

Cited by 63 publications

References 9 publications

Bacterial contamination of weaning foods and drinking water in rural Bangladesh

Bacterial contamination of weaning foods and drinking water in rural Bangladesh

Waterborne transmission and the evolution of virulence among gastrointestinal bacteria

Distinct Sensory Pathways in Vibrio cholerae El Tor and Classical Biotypes Modulate Cyclic Dimeric GMP Levels To Control Biofilm Formation

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