Campylobacter

Campylobacter (meaning "curved bacteria") is a genus of Gram-negative bacteria. Campylobacter typically appear comma- or s-shaped, and are motile. Some Campylobacter species can infect humans, sometimes causing campylobacteriosis, a diarrhoeal disease in humans. Campylobacteriosis is usually self-limiting and antimicrobial treatment is often not required, except in severe cases or immunocompromised patients. The most known source for Campylobacter is poultry, but due to their diverse natural reservoir, Campylobacter spp. can also be transmitted via the air, though this is rare. Other known sources of Campylobacter infections include food products, such as unpasteurised milk and contaminated fresh produce. Sometimes the source of infection can be direct contact with infected animals, which often carry Campylobacter asymptomatically. At least a dozen species of Campylobacter have been implicated in human disease, with C. jejuni (80–90%) and C. coli (5-10%) being the most common. C. jejuni is recognized as one of the main causes of bacterial foodborne disease in many developed countries. It is the number one cause of bacterial gastroenteritis in Europe, with over 246,000 cases confirmed annually. C. jejuni infection can also cause bacteremia in immunocompromised people, while C. lari is a known cause of recurrent diarrhea in children. C. fetus can cause spontaneous abortions in cattle and sheep, and is an opportunistic pathogen in humans. Campylobacter spp. generally appear as curved or comma-shaped rods, and are able to move via unipolar or bipolar flagella. They grow best between 37–42 °C in a microaerophilic environment. When exposed to atmospheric oxygen, C. jejuni is able to change into a coccus form. Most species of Campylobacter are positive by the oxidase test and catalase test and are able to reduce nitrate. The number of known quinolone-resistant Campylobacter strains is growing. It is suggested that this is caused by the overuse of quinolone antibiotics in animal agriculture.