Campylobacter
Campylobacter is a type of bacteria that can cause a diarrheal disease in people. Its name means 'curved bacterium' because the germ typically appears in a comma or s shape. According to its scientific classification, it is a genus of gram-negative bacteria that is motile.
The germ is common in nature and in domestic animals. It is frequently found in raw food of vegetable and animal origin. Its numbers can be very high in some foods, such as raw poultry. Due to their diverse natural reservoir, some Campylobacter can also be detected in the air, although not at an epidemiologically significant level. The disease that some of the species of the bacteria can cause is called campylobacteriosis.
At least a dozen species of Campylobacter have been implicated in human disease, with C. jejuni and C. coli 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 it is an opportunistic pathogen in humans.
Morphology and phenotype
Campylobacter spp. generally appear as curved or comma-shaped rods, and they are able to move via unipolar or bipolar flagella. They grow best between 37 and 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.History
was the first to describe in 1886 what are known today as Campylobacters in the stool samples of infants, who perished from a disease he named "cholera infantum". In the following years until the end of the century, a number of publications appeared, describing the occurrence of such "spirilla" in cases of "cholera-like" and "dysenteric" disease. These organisms were mainly found in the colon or associated with mucus in diarrhoeal stool specimens. Vibrio-like bacteria were also described by Sir John McFadyean and Stockman in 1913 in fetal tissues of aborted sheep. For several years Campylobacters were continuously referred to as Vibrio-like organisms, until 1963 when Sebald and Veron gave the name "Campylobacter" to the genus based on their shape and microaerophilic growth requirement and after showing significant biological differences with Vibrio species.Genomics
The genomes of several Campylobacter species have been sequenced, beginning with C. jejuni in 2000. These genome studies have identified molecular markers specific to members of Campylobacter. Campylobacter spp. genomes are rather small compared to those of other gastrointestinal pathogens, with sizes ranging between 1.60 and 1.90 Mbp. A characteristic of most Campylobacter genomes is the presence of hypervariable regions, which can differ greatly between different strains.Studies have investigated the genes responsible for motility in Campylobacter species. Some Campylobacter species contain two flagellin genes in tandem for motility, flaA and flaB. These genes undergo intergenic recombination, further contributing to their virulence. A single Type VI secretion system cluster was also predicted in approximately one-third of Campylobacter species, grouping into three distinct organisations and harbouring up to five vgrG genes.
Phylogeny
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature and National Center for Biotechnology Information.Campylobacter incertae sedis:
- C. canis Camacho-Suntaxi et al. 2025
- "C. faecalis" Kachler et al. 2000
- "C. felis" Wang et al. 2023
- "C. lawrenceae" Foley et al. 2004
- C. molothri Miller et al. 2025
- "C. ovis" Wang et al. 2023
''Campylobacter''-specific bacteriophages
Pathogenesis
Campylobacter can cause a gastrointestinal infection, campylobacteriosis. The incubation period is 24–72 hours after infection. This is characterized by an inflammatory, sometimes bloody diarrhea or dysentery syndrome, mostly including cramps, fever, and pain. The most common routes of transmission are fecal-oral, ingestion of contaminated food or water, and the eating of raw meat. Foods implicated in campylobacteriosis include raw or under-cooked poultry, raw dairy products, and contaminated produce. Campylobacter is sensitive to the stomach's normal production of hydrochloric acid: as a result, the infectious dose is relatively high, and the bacteria rarely cause illness when a person is exposed to less than 10,000 organisms. Nevertheless, people taking antacid medication are at higher risk of contracting disease from a smaller number of organisms, since this type of medication neutralizes normal gastric acid.In humans, the sites of tissue injury include the jejunum, the ileum, and the colon. Most strains of C. jejuni produce cytolethal distending toxin, which inhibits cell division and impedes activation of the immune system. This helps the bacteria to evade the immune system and survive for a limited time inside intestinal cells. Campylobacter has, on rare occasions, been suggested to cause hemolytic uremic syndrome and thrombotic thrombocytopenic purpura, though no unequivocal case reports exist. Campylobacter infection is the most common trigger of Guillain–Barré syndrome. Gastrointestinal perforation is a rare complication of ileal infection.
Campylobacter has also been associated with periodontitis.
Detection
Campylobacter testing needs to be done to manage the risk of foodborne Campylobacter and reducing the level of foodborne Campoboteriosis, to protect people and to determine if a person is infected with ''Campylobacter.''In humans
Usually, detection of Campylobacter in humans is done by laboratory culturing a stool sample or swab of the rectum collected by a healthcare provider. Results take about 48–72 hours for preliminary results. Confirmation test and testing to determine the species of Campylobacter or drug sensitivities of the organism require additional time.In livestock
Usually, detection of Campylobacter in livestock is done by laboratory culturing a faecal sample. Results take about 48–72 hours.In meat
Usually, detection of Campylobacter in meat is done by laboratory culturing a homogenised sample. Results takes about 48–72 hours.Treatment
The infection is usually self-limiting and, in most cases, symptomatic treatment by liquid and electrolyte replacement is sufficient to treat human infections. Symptoms typically last 5–7 days. Treatment with antibiotics has only a minor effect on the typical duration of the infection in non-complex cases, and is discouraged except in high-risk patients.Diagnosis of campylobacteriosis is made by testing a fecal specimen. Standard treatment in high-risk cases is azithromycin, a macrolide antibiotic, especially for Campylobacter infections in children, although other antibiotics, such as quinolones, tetracycline and other macrolides are sometimes used to treat gastrointestinal Campylobacter infections in adults. In case of systemic infection, other bactericidal antibiotics are used, such as ampicillin, amoxicillin/clavulanic acid, or aminoglycosides. Fluoroquinolone antibiotics, such as ciprofloxacin or levofloxacin, may no longer be effective in some cases, due to resistance. In addition to antibiotics, dehydrated patients may require intravenous fluid treatment in a hospital.