Campylobacter jejuni is isolated from stool using which culture condition?

• A. MacConkey agar at 37°C in aerobic conditions
• B. Campy agar at 42°C under microaerophilic conditions
• C. Blood agar at 25°C in anaerobic conditions
• D. Thioglycollate broth at 35°C in ambient air

Answer: (B)

Campylobacter jejuni needs a specialized culture environment that combines selective nutrients with a reduced-oxygen atmosphere and a higher incubation temperature. It grows best on Campy agar at about 42°C in microaerophilic conditions, which mimic the gut environment of birds where it is common and help suppress competing flora. Aerobic incubation on MacConkey at 37°C, or blood agar at 25°C in anaerobic conditions, or thioglycollate broth at 35°C in ambient air fail to provide either the right temperature or the necessary low-oxygen setting, so they’re not optimal for isolating this organism from stool. This specific combination—Campy agar, 42°C, microaerophilic conditions—offers the most reliable recovery.