Campylobacter

Pathogenic Campylobacter

Campylobacter is a genus of bacteria consisting of non-spore-forming, curved or spiral-shaped, motile 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 diseases in humans:

• Campylobacter jeujini, Campylobacter coli And Campylobacter lari: they represent, in descending order, the species most commonly associated with infection in humans; they mainly cause intestinal infections that accompany 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 all over 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 for pathogenic Campylobacter.

In industrialized countries, Campylobacter infections are much more common than one might think; in the US, for example, campylobacteriosis affects no less than 2 million people each year, and is thought to outweigh Salmonella and Shigella infections combined.

Infection

Most pathogenic Campylobacteria infections result from ingesting drinks or food contaminated with fecal matter from infected animals. Unpasteurized milk is also an excellent vehicle, as is close contact with infected houseplants.Among the foods most at risk we also remember undercooked chicken meat, and minced meat (such as burgers) in general.

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

As compared to Salmonella spp. And Staphylococcus aureus, Campylobacter do not resist for long on surfaces such as Teflon and steel, due to the ability to adhere to them. Consequently, work surfaces and utensils are not called into question as a source of pollution for food. Furthermore, given the low resistance due to adverse environmental conditions and gastric acidity, the risk of foodborne infection by pathogenic Campylobacter is mostly linked to the consumption of raw or undercooked foods, which have suffered from recent fecal pollution.

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

Symptoms

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

Complications

In most cases, the infection remains confined to the intestine and represents a self-limiting pathology, although in the absence of treatment the recovery can take up to a couple of weeks. Only in pediatric subjects, or immunocompromised and severely debilitated, can extra-intestinal infections occur that involve other tracts of the digestive system (pancreatitis, cholecystitis), the joints (reactive arthritis) or the nervous system (Guillan-Barrè syndrome).

Treatment

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

Prevention

As anticipated, the pathogenic Campylobacter are not very resistant in the external environment; for example, they quickly inactivate when exposed to oxygen and low ambient humidity. Even the acidity of the stomach is an "excellent defense against" infection, although not always sufficient to prevent contagion; in this regard, we recall how individuals treated with antisecretory drugs, such as proton pump inhibitors and H2 antagonists are at greater risk of contracting Campylobacter infections.

Given the poor resistance of the bacterium to adverse environmental conditions, cases of epidemic alimentary campylobacteriosis are rare. Prevention is based on cooking food, consuming only drinking water (in a sealed bottle when going to developing countries) and thorough hand cleaning (washing with hot water and soap) after being in contact with animals, including pets, before food preparation and between the handling of raw food and food that has already been prepared.