Campylobacter

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Changed on: 06.12.2017
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Campylobacter are spiral-shaped or curved rod-shaped bacteria. They are relatively sensitive and place great demands on their environment. The bacteria are most comfortable in a microaerophilic environment (less oxygen than in the air, optimum 5 % oxygen), at pH levels between 4.9 and 9.0 and temperatures from 30°C to a maximum of 47 °C. They are rather short lived when exposed directly to air, as they react very sensitively to higher oxygen levels. Although sensitive, they are the most common agents that cause food-borne, bacterial infections in the developed world. At present, there are about four times more Campylobacter infections (Campylobacteriosis) in Austria than there are salmonella infections.

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Campylobacter are spiral-shaped or curved rod-shaped bacteria. They are relatively sensitive and place great demands on their environment. The bacteria are most comfortable in a microaerophilic environment (less oxygen than in the air, optimum 5 % oxygen), at pH levels between 4.9 and 9.0 and temperatures from 30°C to a maximum of 47 °C. They are rather short lived when exposed directly to air, as they react very sensitively to higher oxygen levels. Although sensitive, they are the most common agents that cause food-borne, bacterial infections in the developed world. At present, there are about four times more Campylobacter infections (Campylobacteriosis) in Austria than there are salmonella infections.

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Humans

Campylobacter can cause light to severe diarrhoea in humans. In rare cases, secondary diseases may follow, such as reactive arthritis or the Guillain-Barré Syndrome. Campylobacteriosis occurs worldwide and is one of the most common food-borne infections in Austria and other European countries. Campylobacteriosis has replaced salmonellosis as the predominant intestinal bacterial infection in Austria since 2006.
It takes only a very small amount of the pathogen to cause an infection in the human body. The bacterium is mainly ingested through eating. Important sources of infection are:

  • Raw or insufficiently heated poultry meat and poultry meat products
  • Ready-to-eat meals or food products that have been contaminated with Campylobacter bacteria after cooking or during storage (cross contamination)
  • Unpasteurised milk 
  • Contaminated, untreated drinking water (predominantly in developing countries)
  • Contact with animals (primarily young cats and dogs suffering from diarrhoea).

Animals

The bacteria species Campylobacter is found in numerous apathogenic (harmless) and, in some circumstances, pathogenic (morbid) species of domestic and wild animals. The pathogenic Campylobacter species include both veterinary and human pathogens. The most important veterinary Campylobacter species are Campylobacter fetus types (C. fetus ssp. venerealis, C. fetus ssp. fetus) and C. jejuni.

The most important human pathogenic Campylobacter species found in animals are C. jejuni and C. coli.

These forms can be detected in almost all species of animal to varying distribution levels, prevalence and concentrations. They are widespread among domestic animals, in particular in poultry, but are also common in pigs, ruminants, dogs, cats and pets (rabbits, guinea pigs etc.).

Veterinary Symptoms

Veterinary Campylobacter species (C. fetus species) often result in fertility problems and miscarriages (cattle, sheep) in animals. Illnesses such as diarrhoea in young animals and animals with weak immune systems (poultry, cattle, dogs, cats) or miscarriages (sheep) caused by other species, e.g. C. jejuni, are rarely observed.

Combating methods/Prevention

Combating methods regulated by law are solely in place for C. fetus ssp. venerealis, which is an animal epidemic that must be reported to the authorities.

Combating and prevention methods for all other species of Campylobacter -- in particular with regards to the transmission of the bacteria to humans -- can only be compiled from general, EU-wide and national hygiene regulations for food-producing businesses. These preventative measures include hygiene and pest control on farms and in slaughterhouses (industrial hygiene), as well as staff hygiene for individuals working in meat production and processing.

Detection Methods

Microbiology cultural methods are the main ones used to detect Campylobacter, according to ISO standards. The cultivation of the pathogens requires specific, selective culture mediums or liquid culture mediums with selective additives inhibiting the accompanying bacterial flora -- depending on the test material with or without prior enrichment. The media must be incubated for at least 48 hours at 37-42 °C in a low-oxygen environment (microaerophile).

Additionally, there are also a number of molecularbiological (esp. PCR) and immunological methods (e.g. quick tests) for Campylobacter diagnosis.

Food

To date, there are no limits for Campylobacter in foodstuffs specified in laws or directives at EU and international levels. As a result, it is expert practice to assess ready-to-eat food products in which Campylobacter was detected as harmful. Campylobacter found in food that is not ready to eat is not subject to a complaint as the bacteria should be destroyed during the appropriate preparation process (heating above 70 °C).

Campylobacter was detected in 245 of 365 poultry samples (67%) in 2013; this included 83 cases in 111 samples (75 %) as part of a focus campaign for fresh, raw chicken/chicken parts, 55 cases in 62 samples (89 %) of fresh chicken meat in processing facilities or 61 cases in 100 samples taken from retailers. Milk (products, incl. unpasteurised milk and cheese) was tested 29 times. No Campylobacter was found in any of these samples. Campylobacter was isolated in three out of 46 meat samples (7 %) from various animal species (no poultry). Beef and pork is tested less frequently as Campylobacter does not survive the production conditions (meat is aged, the meat surface dries out), making these foods only a very minor source of infection in humans. There was no evidence of Campylobacter in 84 samples taken from other foods, such as fish, fruit or ready-to-eat products.

How can I protect myself from a food-borne infection?

Food contaminated with Campylobacter cannot be detected by its visual appearance or smell. At present, it is impossible to get 100 % Campylobacter-free chicken broods. As a result, it must be assumed that the pathogen will very likely be present in fresh poultry.

The inappropriate preparation of food, in particular poultry, can easily result in the transmission of the bacteria to other foods (cross contamination). This transmission of pathogens is particularly dangerous, if the contamination occurs to pre-prepared food (Example: thawing liquid drips from a piece of meat onto Tiramisu).

Even if the pathogen generally cannot reproduce in food, the amount could suffice to cause an infection. Deep freezing does not destroy all Campylobacter, just reduces levels present. Only heating food above 70 °C (core temperature, keep for a minimum of 10 minutes) destroys the germs.

Diseases

A total of 5,726 individuals suffered of Campobacteriosis in Austria in 2013, according to the National Zoonosis Report.

There were 133 food-borne infections with a total of 568 patients (108 of whom were hospitalised) documented in Austria in 2013. Fifty-eight outbreaks (44 %) were caused by Campylobacter sp. Thus, Campylobacter sp. was also the predominant outbreak agent in 2013. The infections resulting from the Campylobacter outbreaks made up 23 % of all infection outbreaks (n=128). This correlates with international observations that show Campylobacter outbreaks were mainly identified as minor household outbreaks (two or more members of one single household). The average number of individuals affected by Campylobacter sp. outbreaks was 2.2.

In 14 Campylobacter spp. outbreaks with a reported infection source, eight different food categories were named - most commonly poultry meat (six times), mixed foods (four times) and twice eggs and egg products.


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