Campylobacter species are among the most common pathogens in humans and are commensal in birds, swine, and cattle. The incidence and prevalence of campylobacteriosis have increased in both developed and developing countries over the last 10 years, causing an estimated 92 to 300 million illnesses annually. Although diarrhea is the most frequent clinical manifestation, a broad clinical spectrum is associated with this infection, from asymptomatic carriage to systemic illness. Guillain-Barré syndrome (GBS), reactive arthritis, irritable bowel syndrome, and inflammatory bowel disease have been reported as postinfectious complications of or associations with campylobacteriosis.
PATHOGENESIS AND EPIDEMIOLOGY
Campylobacter organisms are motile, comma-shaped, gram-negative bacilli that derive their name from the Greek words meaning “curved rod.” Campylobacter has been recognized as a pathogen of many animal species including humans. There are 26 species of the genus Campylobacter, of which 17 have been isolated or detected in humans. The species most frequently associated with human infections include C jejuni and C coli. C concisus, C ureolyticus, C upsaliensis, and C lari are emerging Campylobacter species that contribute to the etiology of gastroenteritis. C fetus is an infrequent cause of bacteremia and meningitis in immunocompromised individuals and neonates.
Rates of C jejuni and C coli infection in the United States are more common during the summer months, but cases occur throughout the year. Modes of transmission of Campylobacter differ between economically developed and developing countries. The main vehicles of transmission have been associated with improperly cooked poultry, untreated water, and unpasteurized milk consumption. Campylobacter outbreaks are uncommon in the United States but have occurred in schoolchildren who drank unpasteurized milk. Person-to-person spread occurs occasionally, particularly among very young children, and the risk is greatest during the acute phase of the illness. The incubation period for Campylobacter infection is usually 2 to 5 days, but it can be longer. Person-to-person transmission also has occurred in neonates of infected mothers and has resulted in healthcare-associated outbreaks in nurseries. Excretion usually lasts about 2 to 3 weeks without treatment.
Among Campylobacter isolates reported in FoodNet (2014) with species information, 88% are C jejuni, 9% are C coli, 2% are C upsaliensis, and the remaining 1% are other species. C jejuni is found in the intestinal tract of chickens, turkeys, ducks, ostriches, sheep, cattle, pigs, and other farm animals, all of which serve as reservoirs of infection. Consumption of contaminated poultry, beef, pork, and unpasteurized milk is the leading cause of human foodborne illness. Poultry is estimated to account for 50% to 70% of human Campylobacter infections. Confinement of animals in farms promotes increased carriage and horizontal transmission of Campylobacter.
In the United States, an estimated 1.3 million cases of campylobacteriosis occur each year. It is the second most common bacterial cause of foodborne illness after salmonellosis. The overall incidence of laboratory-confirmed Campylobacter infection in 2015 in the ...