Campylobacter

(endorsed 1996)

Guideline

Escherichia coli (or alternatively thermotolerant coliforms) can be used to indicate the possible presence of pathogenic Campylobacter. If explicitly sought, Campylobacter spp. should not be detected. If detected, advice should be sought from the relevant health authority or drinking water regulator.

General description

Thermophilic Campylobacter spp. are transmitted by the oral route, and cause gastrointestinal illness. Wild birds and poultry are the most important reservoirs of Campylobacter. Other domestic animals, such as pigs, cattle, dogs and cats, are also reservoirs of thermophilic Campylobacter organisms, and so meat, and particularly poultry products and unpasteurised milk, are important sources of Campylobacter infection. Milk may be contaminated with faeces or by secretion of organisms into the milk of cows with mastitis. Recent studies have shown that raw sewage frequently contains from 10 to 105 thermophilic Campylobacter organisms per 100 mL; high counts can be reduced by wastewater treatment processes. Thermophilic campylobacters have been found in crude sewage sludge, but were not detectable in digested conditioned sludge or filter effluent. Their occurrence in surface waters is dependent on rainfall, water temperature and the presence of water fowl.

Several waterborne outbreaks caused by Campylobacter spp. have been reported in the past decade worldwide. The number of people involved ranged from a few to several thousand. Water was implicated in the only two of these outbreaks where Campylobacter was isolated from patients the main sources were found to be unchlorinated surface water and faecal contamination of water storage reservoirs by wild birds. Communities are at risk of outbreaks of campylobacteriosis from the consumption of unchlorinated or inadequately chlorinated surface waters. Contamination of drinking water reservoirs by excrement of water fowl should be controlled, particularly if Campylobacter contamination is suspected. Hygienic precautions should be improved in case the water is distributed without disinfection, or disinfection is interrupted.

Campylobacter spp., like other bacterial pathogens, survive well at low temperatures, and can survive for several weeks in cold groundwater or unchlorinated tap water.

The presence of thermophilic Campylobacter organisms in piped water supplies, whether treated or untreated, suggests a serious fault in the design or management of the system.

Two closely related genera, Helicobacter and Archobactor, include species previously identified in the Campylobacter genus. Helicobacter pylori may be differentiated from Campylobacter spp. by a strong urease activity. It is a cause of gastritis in humans.

Australian significance

Campylobacter have been identified in some Australian water supplies, but there have been no reports of infections from drinking water in Australia. No information is available on Helicobacter spp. in Australian water supplies.

Treatment of drinking water

Provided the water has low turbidity, standard disinfection procedures are sufficient to prevent the spread of Campylobacter in distribution systems.

Method of identification and detection

Campylobacter are Gram-negative, slender, comma-shaped rods which show a characteristic corkscrew-like motion which can be easily seen by phase contrast microscopy. They also appear S-shaped and gullwinged when in pairs. They are microaerophilic, requiring a low oxygen tension (3–6%) for growth.

The numbers of thermophilic Campylobacter spp. in water can be determined by concentration, followed by enrichment, isolation and confirmation (AS4276.19 2014).

Health considerations

Some of the 14 described species are pathogens for humans and animals (for example C. jejuni, C. coli, C. fetus), while others are considered to be nonpathogenic (for example C. sputorum, C. concisus) (Penner 1988). Most the members of the thermophilic group (growing at 42°C) of campylobacters cause enteritis in humans. In Australia, Campylobacter are very important bacterial causes of acute gastroenteritis.

Several major outbreaks of Campylobacter enteritis have been linked to the ingestion of contaminated food, milk or water.

Derivation of guideline

Campylobacter in drinking water can cause acute gastroenteritis and should be absent from drinking water supplies.

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

References

AS4276.19 (2014). Australian Standard. Water microbiology: Examination for thermophilic Campylobacter spp. – Membrane filtration. Standards Australia, Sydney, NSW.

Penner JL (1988). The genus Campylobacter: A decade of progress. Clinical Reviews in Microbiology,1, 157–172.