# Klebsiella ## Guideline ***Coliforms detected in a water supply may include***** Klebsiella spp*****.*** ## General description *Klebsiella* spp. are inherently environmental organisms that survive and sometimes multiply in suitable waters. They are associated with roots of plants and can grow to high levels on the leaves of vegetables. They are frequently present in raw waters, and can increase to high levels in waters containing pulp mill wastes. They are also found in the faeces of a significant proportion of healthy people. *K. pneumoniae* and *K. oxytoca* are significant opportunistic pathogens in hospitals, but the relationship between infections and drinking water is at best dubious, given the wide distribution of members of this genus in the environment. The genus is heterogenous and has been difficult to classify. Four species are now included: *K. pneumoniae, K. oxytoca, K. planticola, and K. terrigena*. A fifth species, *K. mobilis,* has been proposed, but it remains controversial whether this should be classified in this genus or that of *Enterobacter* (Grimont et al. 1991). As the organisms have similar sensitivity to disinfection to *E. coli* and some bacterial enteric pathogens, their presence in drinking water indicates that disinfection has been inadequate. ## Australian significance *Klebsiella* spp. have been detected in Australian drinking water, but there is no evidence that they have caused disease. ## Method of detection and identification *Klebsiella* spp. are Gram-negative nonsporing oxidase-negative rod-shaped bacteria, capable of aerobic and facultatively anaerobic growth in the presence of bile salts or other surface active agents with similar growth-inhibiting properties. They are able to ferment lactose, with the production of acid and gas within 48 hours at 35–37°C. Most *Klebsiella* spp. can be quantified in water by either multiple tube dilution, or membrane filtration methods (AS1095.4.1), which are followed by suitable tests for identification of the genus. ## Health considerations *Klebsiella* may colonise patients in hospital, being spread mainly by the frequent handling which occurs in intensive care units. Those most at risk are people with impaired defence mechanisms, such as the elderly or the very young, people with burns or excessive wounding, those undergoing immunosuppressive therapy, or those with acquired immune deficiency syndrome (AIDS). From colonisation, invasive infections may occur. On rare occasions *Klebsiella* may cause infections, including destructive pneumonia, in apparently healthy people. These problems appear to be associated with *K. pneumoniae* and *K. oxytoca.* ## Derivation of guideline No guideline value is established, if used for operational monitoring, numbers should be established on a system specific basis, taking into consideration relevant historical data and an understanding of the characteristics of the system. *Klebsiella* spp. form a significant proportion of the organisms identified as coliforms in standard tests for indicator bacteria, and these organisms are thus covered by the guideline for coliforms. *** NOTE: Important general information is contained in PART II, Chapter 5 ## References AS1095.4.1 (1981). Microbiological examination of water for dairy purposes. Microbiological methods for the dairy industry. Australian Standard, Standards Association of Australia, Sydney, NSW. Grimont F, Grimont PAD and Richard C (1991). The genus *Klebsiella*. In: Balows A, Truper HG, Dworkin. M, Harder W and Schleifer KH, *The prokaryotes.* Springer-Verlag Publishers, 2nd edition, New York, United States, pp 1217–1224 and 1249–1261. --- # 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/klebsiella.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.