Pathogenic Campylobacter

Campylobacter is a genus of bacteria consisting of motile rod-shaped, curved or spiral-shaped, non-sporing bacilli.

Microaerophilic, gram negative , thermophilic and very labile in the external environment, bacteria belonging to the genus Campylobacter are among the microbial contaminants of greatest concern for human infections from contaminated food .

In particular, among the 15 Campylobacter species currently identified, only four are commonly associated with human disease:

  • Campylobacter jeujini , Campylobacter coli and Campylobacter lari : represent, in descending order, the species most commonly associated with human infection; they mainly cause intestinal infections that are accompanied by the classic symptoms of gastroenteritis .
  • Campylobacter fetus : responsible for extraintestinal infections in the newborn and in immunocompromised subjects.

Campylobacter infections are zoonoses (diseases transmitted by animals) spread throughout the world, which do not spare even the most industrialized countries.

These bacteria are in fact common commensals of many warm-blooded animals, both wild and domestic (cattle, sheep, pigs, dogs, cats, rodents and all varieties of birds), whose gastrointestinal tract represents the main reservoir of pathogenic Campylobacter.In industrialized countries, Campylobacter infections are much more common than one might think; in the USA, for example, campylobacteriosis affects no fewer than 2 million people each year, and is thought to outnumber Salmonella and Shigella infections combined.



Most infections with pathogenic Campylobacteria result from the ingestion of food or drink contaminated with faecal material from infected animals. Unpasteurized milk is also an excellent vehicle, as is close contact with infected apartment animals. Among the foods most at risk we also mention chicken meat that is not cooked enough, and ground meat (such as hamburgers ) in general.

Direct person-to-person transmission via the fecal-oral route is also possible .

Compared to Salmonella spp. and Staphylococcus aureus , Campylobacter do not resist for long on surfaces such as Teflon and steel, due to the incapacity to adhere to them. Consequently, work surfaces and utensils are not implicated as a source of food pollution. Furthermore, given the poor resistance to adverse environmental conditions and gastric acidity , the risk of foodborne infection with pathogenic Campylobacter is mostly linked to the consumption of raw or undercooked foods, which have recently undergone faecal contamination.

In temperate climates, Campylobacter infections are more frequent in the summer and autumn months, affecting to a greater extent pediatric subjects compared to adults and the elderly, who are more resistant to contagion also thanks to the acquisition of specific immunity as a result of previous infections.



The incubation period in humans lasts an average of 2 to 5 days, after which the affected patients complain of symptoms characterized by watery diarrhea , often bloody, with abdominal pain , fever , myalgia , headache , prostration and nausea . therefore indistinguishable from that associated with diseases caused by other enteric pathogens. These symptoms are caused by the powerful enterotoxins released by the bacterium, responsible for a food poisoning that severely damages the cells of the intestinal mucosaand facilitates bacterial invasion. However, the intensity of the symptoms is very variable, so much so that in subjects affected by mild forms the disease can proceed asymptomatically , while in the more severe ones it can take on aspects similar to ulcerative colitis and Crohn’s disease .



In most cases the infection remains confined to the intestine and represents a self-limiting pathology, even if in the absence of treatment healing can take up to a couple of weeks. Extra-intestinal infections involving other tracts of the digestive system ( pancreatitis , cholecystitis ), the joints ( reactive arthritis ) or the nervous system ( Guillan-Barrè syndrome ) can occur only in subjects of pediatric age, or immunocompromised and highly debilitated. .



Being a disease often self-limiting, the body tends to heal spontaneously in the space of a few days, without the need to administer antibiotics . These, in particular erythromycin (the antibiotic of first choice for Campylobacter enteritis ), clarithromycin and azithromycin , can still be useful for accelerating healing and reducing the period in which the bacterium can be passed in the faeces . Unfortunately, antibiotic-resistant strains of Campylobacter have appeared over the years , especially to cephalosporins and penicillin, which complicate the treatment of the infection in the most severe cases. The administration of liquids and electrolytes (rehydration therapy) always represents the essential point of the treatment; in the most severe forms it must be performed intravenously .



As anticipated, the pathogenic Campylobacter are not very resistant in the external environment; for example, they rapidly inactivate when exposed to oxygen and low ambient humidity. Stomach acidity is also an excellent defense against infection, even if not always sufficient to prevent contagion; in this regard, we recall that individuals treated with antisecretory drugs, such as proton pump inhibitors and H2 antagonists , are more exposed to the risk of contracting Campylobacter infections.

Given the low resistance capacity of the bacterium to adverse environmental conditions, cases of food epidemic campylobacteriosis are rare. Prevention is based on cooking food , on the consumption of exclusively potable water (in sealed bottles when traveling to developing countries) and on thorough hand cleaning (washing with hot water and soap) after being in contact with with animals, including pets, before food preparation and between the handling of raw food and already prepared food.



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