## Campylobacter jejuni: Key Characteristics ### Correct Answer: β-lactamase Production and Cephalosporin Resistance **Key Point:** Campylobacter jejuni is NOT intrinsically resistant to cephalosporins via β-lactamase production. In fact, C. jejuni is typically susceptible to third-generation cephalosporins (ceftriaxone, cefotaxime) and fluoroquinolones, making these agents suitable for severe infections. ### Why the Other Options Are Correct | Feature | Details | |---------|----------| | **Microaerophilic growth** | Requires 5% O₂ and 10% CO₂; does not grow in aerobic or anaerobic conditions alone [cite:Prescott Microbiology 10e Ch 39] | | **Gram-negative curved rod** | S-shaped or comma-shaped morphology with characteristic "darting" motility due to bipolar flagella | | **Acute inflammatory diarrhea** | Causes bloody, mucoid stools with fecal leukocytes; invades intestinal epithelium and produces enterotoxin | ### Antibiotic Susceptibility Pattern **High-Yield:** Campylobacter jejuni susceptibility profile: - **Susceptible:** Fluoroquinolones (ciprofloxacin), macrolides (azithromycin), cephalosporins (ceftriaxone) - **Resistant:** Ampicillin (intrinsic), tetracycline (variable) - **Note:** β-lactamase production is NOT the mechanism of resistance in C. jejuni; resistance is due to altered penicillin-binding proteins ### Clinical Pearl Campylobacter is the leading bacterial cause of acute gastroenteritis in developed countries, often associated with poultry consumption. Guillain-Barré syndrome (GBS) can follow C. jejuni infection in 1 per 1000 cases due to molecular mimicry of lipopolysaccharide antigens.
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