Description

Campylobacter species are motile, curved, gram-negative bacilli that are commensal flora of birds, pigs, and cattle and commonly cause bacterial gastroenteritis in humans.

Epidemiology

• Campylobacter infections are among the most common causes of enteritis worldwide, with the highest attack rates in children <4 years of age.
• Asymptomatic infection occurs in 30–100% of chickens, turkeys, and water fowl. Other reservoirs of infection include swine, cattle, sheep, horses, rodents, and household pets (especially young pets).
• Contaminated water and unpasteurized milk and milk products are other sources of infection.
• Infections typically occur sporadically, without outbreaks.

Risk Factors

• Approximately 40% of Campylobacter enteritis is estimated to be attributable to undercooked chicken consumption.
• Other risk factors for Campylobacter enteritis include international travel, direct contact with farm animals, chronic disease, poor food preparation hygiene, consumption of chicken prepared outside the home, and use of acid-suppressive medications.
• Children are at higher risk relative to adults.
• In low resource settings, breastfeeding and routine treatment of drinking water are protective among children <2 years of age.
• Frequent exposure to Campylobacter (e.g., among food handlers and abattoir workers) may protect against disease.
• Person-to-person transmission of C. jejuni has been reported when index cases were young children incontinent of feces or as vertical transmission from mother to neonate.
• Asymptomatic hospital personnel or food handlers have not been implicated as sources.

General Prevention

• Hand washing after contact with animals or animal products, cleaning cooking utensils and cutting boards after contact with raw poultry, proper cooling and storage of foods, pasteurization of milk, and chlorination of water supplies decrease the risk for infection.
• Diapered infants with symptomatic infection should be excluded from child care until resolution of diarrhea.
• No licensed vaccines currently exist, but C. jejuni strains with decreased risk of secondary Guillain-Barré syndrome (GBS) are being developed as candidates for capsular polysaccharide conjugate vaccines.

Pathophysiology

• Transmission of disease is by the fecal–oral route from contaminated food and water or by direct contact with fecal material from animals or persons infected with the organism.
• As few as 500 organisms may be required to produce infection.
• Campylobacter spp. possess one or two flagella that provide the organism’s motility and facilitate intestinal colonization.
• C. jejuni adheres to epithelial cells and mucus, secretes cytotoxins (which play a role in the development of watery diarrhea), can invade intestinal epithelial cells using a microtubule entry system, and induces an inflammatory ileocolitis.
• Campylobacter can cause a range of clinical manifestations, including enteritis and rare localized extraintestinal infections.
• Bacteremia, although uncommon, can occur, especially in the neonate and immunocompromised host; Campylobacter fetus is the species most likely to be isolated. C. fetus can also cause neonatal meningitis.
• Campylobacter upsaliensis, Campylobacter lari, and Campylobacter hyointestinalis have been identified in immunocompromised individuals and are usually associated with a self-limiting enteritis but can occasionally cause systemic illness.

Etiology

• Campylobacter is a motile, curved, microaerophilic, non–lactose-fermenting, oxidase-positive, gram-negative rod that requires oxygen and carbon dioxide for optimal growth.
• Three main Campylobacter species involved in human infections include C. jejuni, C. coli (which cause enteritis), and C. fetus (implicated in systemic illness in neonates and compromised hosts). Rarer human pathogens include Campylobacter concisus, Campylobacter curvus, C. hyointestinalis, C. lari, Campylobacter rectus, Campylobacter sputorum, and C. upsaliensis.

Commonly Associated Conditions

Campylobacteriosis occurs in both healthy and immunocompromised individuals.