# Vibrio ## Guideline **Escherichia coli *****(or alternatively thermotolerant coliforms) are used to indicate the presence of pathogenic***** Vibrio *****spp. If explicitly sought, pathogenic***** Vibrio *****spp. should not be detected. If detected, advice should be sought from the relevant health authority or drinking water regulator.*** ## General description *Vibrio* species may be waterborne. Cholera (*V. cholerae* O1 and O139), for example, is usually a water-associated disease and numerous such outbreaks have been documented. Food-borne outbreaks, however, are also common and person-to-person transmission may occur under conditions of extreme crowding and poor hygiene. The transmission of cholera has been extensively reviewed, and although water is undoubtedly an important vehicle for transmission, many aspects of the epidemiology of cholera remain open to debate (Miller et al. 1985). There is evidence to suggest that in some circumstances, *V. cholerae*, including serotype O1 and O139, may occur naturally in some surface waters. ## Australian significance *Vibrio* spp. have been isolated from a number of source waters in Queensland, but not from reticulated waters. There are no published associations between the isolation of Vibrios from source water and health effects in the community. ## Treatment of drinking water Standard disinfection procedures eliminate *V. cholerae* O1 and O139 (the source of the classic cholera epidemics) from reticulated water, provided turbidity is low. ## Method of identification and detection *Vibrio* spp. are nonsporing, slightly curved Gram-negative rods, motile by a single polar flagellum. Their metabolism is both respiratory and fermentative without the production of gas, while their growth is aerobic and facultatively anaerobic. Both catalase and oxidase are formed and nitrates are reduced to nitrites (APHA method 9260H 1992, AS4276.15 2014). ## Health considerations *Vibrio cholerae* is a well-defined species frequently found in source waters. While cases of diarrhoea are caused by other types, only the serovars O1 and O139 are associated with the classical cholera symptoms in which a proportion of cases suffer fulminating and severe watery diarrhoea. The O1 serovar has been further divided into ‘classical’ and ‘El Tor’ biotypes, the latter distinguished by (*inter alia*) the ability to produce a dialysable, heat-labile haemolysin, active against sheep and goat red blood cells. When present in large numbers in the intestinal mucosa, *V. cholerae* O1 produces an enterotoxin (cholera toxin) that alters the ionic fluxes across the mucosa with resulting catastrophic loss of water and electrolytes in liquid stools. Almost all the organisms that are known to cause epidemic cholera are members of the serogroups O1 and O139, though the very similar *V. mimicus* (sucrose nonfermenter) has been isolated from cases of clinical cholera. ## Derivation of guideline The isolation of *V. cholerae* O1 and O139 from water used for drinking is of major public health importance. However, other serogroups of *V. cholerae* are part of the normal flora of some waters. *V. cholerae* and other pathogenic *Vibrio* spp. should be absent from drinking water supplies. ### References APHA Method 9260H, (1992). Detection of pathogenic bacteria: *Vibrio cholerae*. Standard Methods for the Examination of Water and Wastewater, 18th edition. American Public Health Association, Washington DC. AS4276.15 (2014). Australian Standard. Water microbiology: Examination for *Vibrio cholera*. Standards Australia, Sydney, NSW. Miller CJ, Drasar BJ and Feachem RG (1985). Cholera epidemiology in developed and developing countries: New thoughts on transmission, seasonality and control. *Lancet,* i, 261–263. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://guidelines.nhmrc.gov.au/australian-drinking-water-guidelines/part-5/microorganisms/bacteria/vibrio.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.