Diseases
C. jejuni is a frequent cause of enterocolitis, especially in children. C. jejuni infection is a common antecedent to Guillain Barré syndrome. Other Campylobacter species, such as C. intestinalis, are rare causes of systemic infection, particularly bacteremia.
Important Properties
Campylobacters are curved, gram-negative rods that appear either comma- or S-shaped. They are microaerophilic, growing best in 5% oxygen rather than in the 20% present in the atmosphere. C. jejuni grows well at 42°C, whereas Campylobacter intestinalis4 does not—an observation that is useful in microbiologic diagnosis.
Pathogenesis & Epidemiology
Domestic animals such as cattle, chickens, and dogs serve as a source of the organisms for humans. Transmission is usually fecal–oral. Food and water contaminated with animal feces are the major sources of human infection. Foods, such as poultry, meat, and unpasteurized milk, are commonly involved. Puppies with diarrhea are a common source for children. Human-to human transmission occurs but is less frequent than animal-to human transmission.
C. jejuni is a major cause of diarrhea in the United States; it was recovered in 4.6% of patients with diarrhea, compared with 2.3% and 1% for Salmonella and Shigella, respectively. C. jejuni is the leading cause of diarrhea associated with consumption of unpasteurized milk.
Features of pathogenesis by Campylobacter are described in Table 1. Inflammation of the intestinal mucosa often occurs, accompanied by blood in stools. Systemic infections (e.g., bacteremia) occur most often in neonates or debilitated adults.
Table1. Important Features of Pathogenesis by Curved Gram-Negative Rods Affecting the Gastrointestinal Tract
Clinical Findings
Enterocolitis, caused primarily by C. jejuni, begins as watery, foul-smelling diarrhea followed by bloody stools accompanied by fever and severe abdominal pain. Systemic infections, most commonly bacteremia, are caused more often by C. intestinalis. The symptoms of bacteremia (e.g., fever and malaise) are associated with no specific physical findings.
Gastrointestinal infection with C. jejuni is associated with Guillain-Barré syndrome, the most common cause of acute neuromuscular paralysis. Guillain-Barré syndrome is an autoimmune disease attributed to the formation of antibodies against C. jejuni that cross-react with antigens on neurons. Infection with Campylobacter is also associated with reactive arthritis.
Laboratory Diagnosis
If the patient has diarrhea, a stool specimen is cultured on a blood agar plate containing antibiotics5 that inhibit most other fecal flora. The plate is incubated at 42°C in a microaerophilic atmosphere containing 5% oxygen and 10% carbon dioxide, which favors the growth of C. jejuni. It is identified by failure to grow at 25°C, oxidase positivity, and sensitivity to nalidixic acid. Unlike Shigella and Salmonella, lactose fermentation is not used as a distinguishing feature. If bacteremia is suspected, a blood culture incubated under standard temperature and atmospheric conditions will reveal the growth of the characteristically comma- or S-shaped, motile, gram-negative rods. Identification of the organism as C. intestinalis is confirmed by its failure to grow at 42°C, its ability to grow at 25°C, and its resistance to nalidixic acid.
Treatment & Prevention
Erythromycin or ciprofloxacin is used successfully in C. jejuni enterocolitis.
There is no vaccine or other specific preventive measure. Proper sewage disposal and personal hygiene (handwashing) are important.
