The majority of Campylobacter species are pathogenic and associated with a wide variety of diseases in humans and other animals. These organisms demonstrate consider able ecologic diversity. Campylobacter spp. are microaerophilic (5% to 10% O2) inhabitants of the gastrointestinal tracts of various animals, including poultry, dogs, cats, sheep, and cattle, as well as the reproductive organs of several species. When random fecal samples from chicken carcasses from butcher shops in the New York City area were tested for Campylobacter, 83% of the samples yielded more than 10 colony-forming units per gram of feces. In general, Campylobacter spp. produce three syndromes in humans: febrile systemic disease, periodontal disease, and, most commonly, gastroenteritis. Arcobacter species appear to be associated with gastro enteritis. Studies have indicated that A. butzleri was the fourth most common Campylobacter-like organism isolated from stool and was associated with a persistent, watery diarrhea. In addition, more recent data indicate that Arcobacter is underreported in gastrointestinal infections and diarrhea throughout many European countries. The organism is found in the environment and in untreated water. It is also prevalent in commercially pre pared meats including chicken, beef, pork, lamb, and poultry.
Within the genus Campylobacter, C. jejuni and C. coli are commonly associated with infections in humans and are transmitted via contaminated food, milk, or water. Out breaks have been associated with contaminated drinking water and improperly pasteurized milk, among other sources. In contrast to other agents of foodborne gastro enteritis, including Salmonella and staphylococci, Campylobacter spp. does not multiply in food. Other campylobacters have been isolated from patients as a result of consumption of untreated water, immunocompromised patients, or patients recently returned from international travel. C. jejuni subsp. doylei has been isolated from children with diarrhea and from gastric biopsies in adults. In developed countries, the majority of C. jejuni infections are transmit ted by direct contact during the preparation and eating of chicken. Person-to-person transmission of Campylobacter infections plays only a minor role in the transmission of disease. There is a marked seasonality with the rates of C. jejuni infection in the United States; the highest rates of infection occur in late summer and early fall. Campylobacter spp. has been recognized as the most common etiologic agent of gastroenteritis in the United States.
Although infections with C. jejuni are evident as a result of acute inflammatory enteritis of the small intestine and colon, the pathogenesis remains unclear. However, multiplication of organisms in the intestine leads to cell damage and an inflammatory response. Blood and polymorphonuclear neutrophils are often observed in patient stool specimens. Most strains of C. jejuni are susceptible to the nonspecific bactericidal activity of normal human serum; this susceptibility prob ably explains why C. jejuni bacteremia is uncommon.
