Infections Due to Campylobacter and Related Organisms¶
Chapter 169 | Part 5: Infectious Diseases
KEY CLINICAL POINTS¶
- Campylobacter jejuni is the most common cause of bacterial gastroenteritis, accounting for 80–90% of campylobacter-related illnesses.
- Antibiotic resistance is rising, with ~27% of U.S. Campylobacter isolates resistant to ciprofloxacin and higher rates globally.
- Complications include reactive arthritis (2.5% of cases) and Guillain-Barré syndrome (1 in 1000–2000 cases).
- C. fetus infections are more severe, with higher mortality (12%) and risk of systemic complications like endocarditis.
- Diagnosis relies on stool cultures, PCR, or direct microscopy, with MALDI-TOF for species identification.
1. DEFINITION & OVERVIEW¶
Campylobacter and related genera (Arcobacter, Helicobacter) cause a range of infections, primarily gastrointestinal. Campylobacter jejuni is the prototypical pathogen, while C. fetus causes systemic infections. Helicobacter pylori, though not a Campylobacter species, is discussed due to its association with gastric disease.
Table 169-1: Clinical Features of Atypical Campylobacter and Related Species¶
| SPECIES | COMMON CLINICAL FEATURES | LESS COMMON CLINICAL FEATURES | ADDITIONAL INFORMATION |
|---|---|---|---|
| Campylobacter coli | Fever, diarrhea, abdominal pain | Bacteremia | Clinically indistinguishable from C. jejuni |
| Campylobacter fetus | Bacteremia, sepsis, meningitis | Diarrhea, relapsing fevers | Not usually isolated from media containing cephalothin |
| Campylobacter upsaliensis | Watery diarrhea, low-grade fever | Bacteremia, abscesses | Difficult to isolate due to cephalothin susceptibility |
| Campylobacter hyointestinalis | Watery/bloody diarrhea, vomiting | Bacteremia | Causes proliferative enteritis in swine |
| Helicobacter fennelliae | Chronic mild diarrhea, abdominal cramps | Bacteremia | Best treated with fluoroquinolones |
| Arcobacter cryaerophilus | Diarrhea | Bacteremia | Poultry, seafood sources; cultured aerobically |
| SPECIES | COMMON CLINICAL FEATURES | LESS COMMON CLINICAL FEATURES | ADDITIONAL INFORMATION |
|---|---|---|---|
| Arcobacter butzleri | Fever, diarrhea, abdominal pain | Bacteremia, appendicitis | Enzootic in nonhuman primates |
| Campylobacter sputorum | Pulmonary, perianal abscesses | Bacteremia | Three biovars: sputorum, faecalis, paraureolyticus |
1.1 Genus Classification¶
Campylobacter, Arcobacter, and Helicobacter are distinct genera. C. jejuni and C. fetus are the primary human pathogens, while H. pylori is a separate gastric pathogen.
1.2 Clinical Spectrum¶
Infections range from self-limiting gastroenteritis to systemic bacteremia, sepsis, and extraintestinal complications (e.g., meningitis, endocarditis).
2. EPIDEMIOLOGY¶
Campylobacter infections are hyperendemic in developing countries, with ~20 cases per 100,000 globally. Poultry is the primary reservoir, with transmission via undercooked meat, contaminated water, or animal contact. C. fetus infections are more common in immunocompromised hosts.
2.1 Transmission¶
Primary routes: contaminated poultry (30–70% of cases), raw milk/untreated water, animal contact (dogs, cats, birds), and travel to endemic regions. Puppies are a notable source of C. fetus.
2.2 Risk Factors¶
Young children, elderly, immunocompromised (AIDS, diabetes, neoplasia), and those with proton pump inhibitor use. C. fetus infections peak in extremes of age.
3. ETIOLOGY & PATHOPHYSIOLOGY¶
C. jejuni causes acute gastroenteritis via motility and adhesion. C. fetus has a capsule (S-layer) that resists complement-mediated killing, enabling systemic spread. H. pylori, though not Campylobacter, is discussed for its role in gastric cancer.
3.1 C. jejuni Pathogenesis¶
Motility and adhesion to intestinal epithelium drive inflammation. Cytotoxins and enterotoxins play minimal roles. Tissue invasion and bacteremia are clinically significant.
3.2 C. fetus Pathogenesis¶
Capsule (S-layer) prevents phagocytosis. Antigenic variation of S-layer proteins contributes to chronic infections. Systemic spread to vascular sites causes endocarditis, mycotic aneurysms, and septic thrombophlebitis.
4. CLINICAL FEATURES¶
Acute gastroenteritis (diarrhea, fever, abdominal pain) is common. Extraintestinal manifestations include bacteremia, meningitis, and reactive arthritis. Guillain-Barré syndrome occurs in 1 in 1000–2000 cases.
4.1 Intestinal Phase¶
Prodrome: fever, headache, myalgia. Diarrhea (watery to bloody), abdominal cramps, and fever. Most cases resolve within 1–2 weeks.
4.2 Extraintestinal Manifestations¶
Bacteremia, septic arthritis, endocarditis, and meningitis. C. fetus infections may present as relapsing fever or septic abortion.
5. DIFFERENTIAL DIAGNOSIS¶
Differentiate from Salmonella, Shigella, Yersinia, and enterohemorrhagic E. coli. Exclude inflammatory bowel disease (IBD) until Campylobacter is ruled out, especially in travelers or immunocompromised patients.
6. INVESTIGATIONS & DIAGNOSIS¶
Diagnosis via stool culture (selective media), PCR, or direct microscopy. Blood cultures may detect bacteremia. MALDI-TOF identifies species. CIDTs are sensitive but may have false positives.
6.1 Diagnostic Methods¶
Stool cultures on Campylobacter-specific media, Gram-stained smears, and PCR. Blood cultures for bacteremia. Phase-contrast/dark-field microscopy for motility.
7. MANAGEMENT & TREATMENT¶
Fluid resuscitation is critical. Antibiotics are indicated for severe cases, persistent diarrhea, or immunocompromised hosts. Resistance to fluoroquinolones and macrolides is common.
7.1 First-line Therapy¶
Azithromycin (500 mg daily x 3 days) or fluoroquinolones (ciprofloxacin 500 mg BID x 3 days). PPIs enhance efficacy when combined with antibiotics.
7.2 Resistance Considerations¶
Ciprofloxacin resistance >27% in U.S. isolates. Avoid clarithromycin in prior-exposed patients. Use carbapenems (imipenem/meropenem) for severe bacteremia.
7.3 Special Cases¶
Immunocompromised patients require prolonged therapy (7–14 days). C. fetus infections may need 4 weeks of antibiotics. Lifelong prophylaxis for recurrent infections.
8. PROGNOSIS & COMPLICATIONS¶
Most patients recover spontaneously. Complications include reactive arthritis (10% of cases), Guillain-Barré syndrome (1 in 1000–2000), and septicemia. C. fetus infections have 12% mortality.
8.1 Postinfectious Sequelae¶
Reactive arthritis (knees, wrists, small joints) and Guillain-Barré syndrome (Miller Fisher variant). Autoimmune mimicry via sialylated lipopolysaccharides.
9. SPECIAL CONSIDERATIONS¶
Pregnancy: Risk of fetal death. Elderly: Higher mortality. Immunocompromised: Severe, persistent infections. Avoid antimotility agents (may cause toxic megacolon).
10. KEY POINTS & CLINICAL PEARLS¶
- Campylobacter is the leading cause of bacterial gastroenteritis globally. 2. Antibiotic resistance is rising, especially to fluoroquinolones. 3. Reactive arthritis and Guillain-Barré syndrome are rare but significant complications. 4. C. fetus infections are more severe and require prolonged therapy. 5. Use PPIs with antibiotics to enhance eradication rates.