Campylobacter species are motile, curved, microaerophilic, gram-negative bacilli that normally inhabit the gastrointestinal tract of many domestic animals and fowl.
Several species are human pathogens. The major pathogens are C. jejuni and C. fetus.
C. jejuni is a common food-borne pathogen that affects healthy and compromised people. It causes diarrhea in all age groups, although peak incidence appears to be from age 1 to 5 years. C. jejuni accounts for more cases of diarrhea in the US than Salmonella and Shigella combined. C. jejuni can cause meningitis in infants.
C. fetus and several others typically cause bacteremia and systemic manifestations in adults, more often when underlying predisposing diseases, such as diabetes, cirrhosis, cancer, or HIV/AIDS, are present. C. fetus is much less common than C. jejuni and is usually an opportunistic pathogen affecting people with underlying disease, older people, and pregnant women. In pregnant patients, the rate of fetal loss can be as high as 70%. C. fetus infections in healthy hosts occur in those with occupational exposure to infected animals. In patients with immunoglobulin deficiencies, these organisms, including C. jejuni, may cause difficult-to-treat, relapsing infections.
The following have been implicated in outbreaks:
Person-to-person transmission through fecal-oral and sexual contact may also occur but is uncommon because a large number of Campylobacter organisms are required to cause infection. Transmission of Campylobacter infection does occur among men who have sex with men. However, in sporadic cases, the source of the infecting organism is frequently obscure.
C. jejuni diarrheal illness is associated with subsequent development of Guillain-Barré syndrome (GBS) because of cross-reaction between C. jejuni antibodies and human gangliosides. Although only 1 case of GBS is estimated to occur per 2000 C. jejuni infections, about 25 to 40% of patients who develop GBS have had a prior C. jejuni infection.
Postinfectious (reactive) arthritis may occur in human leukocyte antigen (HLA)-B27–positive patients a few days to several weeks after an episode of C. jejuni diarrhea. Other postinfectious complications include uveitis, hemolytic anemia, hemolytic-uremic syndrome, myopericarditis, immunoproliferative small intestinal disease, septic abortion, and encephalopathy.
Focal extraintestinal infections (eg, endocarditis, meningitis, septic arthritis) occur rarely with C. jejuni but are more common with C. fetus.
The most common manifestation of Campylobacter infection is an acute, self-limited gastrointestinal illness characterized by watery and sometimes bloody diarrhea. Fever (38 to 40° C), which follows a relapsing or intermittent course, is the only constant feature of systemic Campylobacter infection, although abdominal pain (typically in the right lower quadrant), headache, and myalgias are frequent.
Patients can also present with subacute bacterial endocarditis (more often due to C. fetus), reactive arthritis, meningitis, or an indolent fever of unknown origin rather than with diarrheal illness. Joint involvement with reactive arthritis is usually monoarticular, affecting the knees; symptoms resolve spontaneously over 1 week to several months.
Diagnosis, particularly to differentiate Campylobacter infection from ulcerative colitis, requires microbiologic evaluation. Stool culture should be obtained plus blood cultures for patients with signs of focal infection or serious systemic illness. White blood cells are present in stained smears of stool.
Rapid molecular and antigen assay stool tests are also available.
Most enteric infections resolve spontaneously; if they do not, azithromycin 500 mg orally once a day for 3 days may be helpful.
Because resistance to ciprofloxacin is increasing, this drug should be used judiciously.
For patients with extraintestinal infections, antibiotics (eg, imipenem, gentamicin, ampicillin, a 3rd-generation cephalosporin, erythromycin) should be given for 2 to 4 weeks to prevent relapses.