# Salmonella ## Guideline **Escherichia coli *****(or alternatively thermotolerant coliforms) are used to indicate the possible presence of***** Salmonella *****spp. If explicitly sought,***** Salmonella *****spp. should not be detected. If detected, advice should be sought from the relevant health authority or drinking water regulator.*** ## General description *Salmonella* spp. are widely distributed in the environment and gain entry into water systems though faecal contamination from livestock, native animals, drainage waters and incompletely treated waste discharges. Faecal contamination of water which is inadequately treated or inadequately disinfected is the main cause of waterborne outbreaks of salmonellosis. ## Australian significance *Salmonella* has been isolated from a number of source waters in Australia and occasionally from reticulated waters. However, published associations between the isolation of *Salmonell*a from drinking water and health effects in the community are mainly anecdotal. Most illnesses resulting from *Salmonella* infection are derived from contaminated foodstuffs, e.g. poultry and livestock. Waterborne *Salmonella* spp. play only a minor role in causing disease. ## Treatment of drinking water Treatment by disinfection using chlorine is usually effective against *Salmonella* spp., provided the water has low turbidity. ## Method of identification and detection The numbers of *Salmonella* in water can be determined by concentration followed by enrichment, isolation and confirmation (AS4276.14 2014). ## Health considerations *Salmonella* spp., with the exception of those that cause enteric fever in humans (Lloyd 1983), are pathogens of animals, which provide important reservoirs for the infection of humans. *Salmonella* Typhi, however, is a specific human pathogen. In particular, *S*. Typhi, *S*. Paratyphi A, and *S*. Paratyphi B are able to invade tissues and cause a septicaemia with high temperature rather than diarrhoea. This is known as enteric fever. In humans, most of the other serovars cause a transient intestinal infection which results in acute gastroenteritis with diarrhoea. Certain serovars are highly pathogenic for humans, while others appear nonpathogenic. Many *Salmonella* infections are symptomless. Epidemiological and volunteer studies show that the infective dose of *Salmonella* varies considerably. Method of intake, individual host susceptibility, and virulence of the particular strain are important in determining the dose required to produce an infection. Waterborne outbreaks due to substantial contamination are usually characterised by rapid onset. The majority of cases develop over a period of a few days, and these may be followed by secondary cases. The spatial distribution of infections in major outbreaks is often strongly correlated with the water supply system. ## Derivation of guideline The presence of faecal indicator bacteria is useful to determine the possible presence of *Salmonella* spp. However, as with many other pathogens, *Salmonella* spp. may occasionally be present when indicators are absent, particularly where a supply may have been subject to faecal contamination by amphibians (frogs) and reptiles. It is also important, therefore, to test directly for Salmonellae if contamination is suspected. The direct effect on the community of noncompliance with the guideline will depend on the *Salmonella* species involved. The numbers of *Salmonella* may be amplified through contamination of foodstuffs. ## References AS4276.14, (2014). Australian Standard. Water microbiology: Detection of *Salmonella* spp. Standards Australia, Sydney, NSW. Lloyd B (1983). *Salmonella,* enteric fever and salmonelloses. In: Feachem RG, Bradley DJ et al. (editors). *Health aspects of excreta and wastewater management*. Chichester, John Wiley and Sons, pp 251–286. --- # 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/salmonella.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.