Helicobacter pylori

(endorsed 2011)

Guideline

No guideline value has been set for Helicobacter pylori in drinking water and its inclusion in routine monitoring programs is not recommended.

A multiple barrier approach from catchment to tap is recommended to minimise the risk of contamination. Protection of water supplies from human waste is a priority. Operation of barriers should be monitored to ensure effectiveness and that microbial health-based targets are being met.

General description

Helicobacter pylori, originally classified as Campylobacter pylori, is a Gram-negative, micro-aerophilic, spiral-shaped, motile bacterium that is able to colonise the stomach. Although not an acidophile, it is able to tolerate the acidic conditions in the stomach. There are at least 14 species of Helicobacter, but only H. pylori has been identified as a human pathogen. It has a narrow host range and is found primarily in humans and some other primates.

H. pylori has been detected in water. Although it is unlikely to grow in the environment, it has been found to survive for more than 4 days in water (Azevedo et al. 2008) and there is evidence that it can be present in biofilms (Park et al. 2001). In a US study, H. pylori was found in a majority of surface water and shallow groundwater samples; its presence was not correlated with the presence of Escherichia coli (Hegarty et al. 1999).

The community prevalence of H. pylori varies: in developing countries it can exceed 80%, while in developed countries, prevalence is typically below 40% and is decreasing. In developing countries infections have been associated with poor and overcrowded living conditions. Interfamilial clustering is common (Kusters et al. 2006).

H. pylori has been detected in saliva, vomit and faeces, but there is evidence that it is sensitive to bile salts, and this will reduce faecal excretion. Person-to-person contact within families has been identified as the most likely source of infection through oral-oral transmission. Faecal-oral transmission is considered possible and consumption of contaminated drinking water has been suggested as a potential source of infection; however, evidence to date is limited to developing countries and further investigation is required to determine whether waterborne transmission occurs (Percival et al. 2004).

Australian significance

Surveys of seroprevalence have indicated a pattern similar to that found in other developed countries. Antibodies to H. pylori have been detected in about 30% of Victorian adults, with seropositivity increasing with age (Robertson et al. 2003).

Preventing contamination of drinking water

H. pylori has been detected in human vomit and faeces but the organism does not grow or survive indefinitely in water. Hence protection of drinking water supplies from human waste will minimise the likelihood of contamination. H. pylori is sensitive to chlorination (Johnson et al. 1997).

Method of identification and detection

There is no standard method for isolating and culturing H. pylori from water; however, it can be grown on culture media.

Health considerations

H. pylori is found in the stomach; although most infections are asymptomatic, the organism is associated with chronic gastritis, which may lead to complications such as peptic and duodenal ulcer disease and gastric cancer. The majority of H. pylori infections are initiated in childhood and, unless treated, are chronic.

Derivation of guideline

No guideline value is proposed for H. pylori and inclusion in routine verification monitoring programs is not recommended. The focus should be on monitoring of control measures for H. pylori, including prevention of contamination by human waste, and effective disinfection. E. coli is not a reliable indicator for the presence/absence of H. pylori.

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NOTE: Important general information is contained in PART II, Chapter 5

References

Azevedo NF, Almeida C, Fernandes I, Cerqueira L, Dias S, Keevil CW, Vieira MJ (2008). Survival of gastric and enterohepatic Helicobacter spp in water: implications for transmission. Applied and Environmental Microbiology, 74:1805-1811.

Hegarty JP, Dowd MT, Baker KH (1999). Occurrence of Helicobacter pylori in surface water in the United States. Journal of Applied Microbiology, 87:697-701.

Johnson CH, Rice EW, Reasoner DJ (1997). Inactivation of Helicobacter pylori by chlorination. Applied and Environmental Microbiology, 63:4969-4970.

Kusters JG, van Vliet AHM, Kuipers, EJ (2006). Pathogenesis of Helicobacter pylori infection. Clinical Microbiology Reviews, 19:449-490.

Park SR, Mackay WG, Reid DC (2001). Helicobacter sp. recovered from drinking water biofilm sampled from a water distribution system. Water Research, 35:1624-1626.

Percival S, Chalmers R, Embrey M, Hunter P, Sellwood J, Wyn-Jones P (2004). Microbiology of Waterborne diseases. Elsevier Academic Press, London UK.

Robertson MS, Cade JF, Savoia HF, Clancy RL (2003). Helicobacter pylori infection in the Australian community: current prevalence and lack of association with ABO blood groups. Internal Medicine Journal, 33:63-167.