What antibiotic should be prescribed for a patient with a positive test result for Campylobacter (C.) coli, jejuni, or upsaliensis?

Treatment of Campylobacter Infection

Prescribe azithromycin as first-line therapy for this patient with Campylobacter coli, jejuni, or upsaliensis infection. 1, 2

Recommended Antibiotic Regimen

Azithromycin is the preferred treatment with two dosing options:

• For severe cases or dysentery: 1000 mg single oral dose 1, 2
• For less severe cases: 500 mg orally daily for 3 days 1, 2

The choice between these regimens depends on severity markers including high fever (>38.5°C), bloody diarrhea, or signs of systemic illness. 1

Why Azithromycin Over Fluoroquinolones

Fluoroquinolone resistance has rendered ciprofloxacin unreliable for Campylobacter treatment:

• Fluoroquinolone resistance rates exceed 90% in Southeast Asia and have increased dramatically worldwide from 0% to 84% in Thailand between 1990-1995 1
• Clinical failure occurs in approximately 33% of patients treated with fluoroquinolones when the isolate is resistant 1, 2
• Azithromycin maintains low resistance rates at approximately 4% for travel-related infections 1, 2
• In a head-to-head trial, azithromycin achieved zero treatment failures versus 2 clinical and 6 bacteriologic failures with ciprofloxacin 3

While ciprofloxacin is FDA-approved for infectious diarrhea caused by Campylobacter jejuni 4, current resistance patterns make it unsuitable as empiric therapy unless local susceptibility testing confirms low resistance rates. 1, 2

Timing Considerations

Early treatment initiation is critical for maximum benefit:

• Starting azithromycin within 72 hours of symptom onset reduces illness duration from 50-93 hours to 16-30 hours 1, 2
• Delaying treatment beyond 72 hours significantly reduces antibiotic effectiveness 1, 2

Special Population Considerations

Immunocompromised patients require treatment regardless of symptom severity:

• Always treat immunocompromised patients, even with mild infections, due to high risk of bacteremia and systemic spread 1, 2
• Cancer patients and other immunosuppressed individuals should receive azithromycin as first-line therapy 1

Pediatric dosing differs from adults:

• For children: azithromycin 30 mg/kg as a single dose (shown superior to 20 mg/kg dose and to erythromycin 50 mg/kg/day for 5 days) 5
• Infants under 6 months warrant prompt treatment due to higher risk for severe disease 1

Essential Supportive Care

Rehydration is critical alongside antibiotic therapy:

• Initiate oral rehydration solutions (Ceralyte, Pedialyte) for most patients with severe diarrhea or dehydration signs 1
• Administer IV fluids and electrolytes for complicated cases with fever, vomiting, or significant fluid depletion 1

Avoid antimotility agents (loperamide) as they may prolong bacterial shedding and worsen outcomes, particularly with bloody diarrhea or fever. 1, 2

Common Pitfalls to Avoid

• Do not use fluoroquinolones empirically without confirmed susceptibility testing, as this leads to treatment failure in one-third of resistant cases 1, 2
• Do not delay treatment beyond 72 hours, as this substantially reduces antibiotic efficacy 1, 2
• Do not discontinue antibiotics prematurely before completing the full 3-day course, as this can lead to treatment failure 1

Monitoring and Follow-Up

Reassess if no improvement occurs within 48 hours:

• Consider alternative antibiotics based on susceptibility testing if available 1
• Evaluate for complications including Guillain-Barré syndrome, reactive arthritis, or hemolytic-uremic syndrome in patients with persistent or worsening symptoms 1
• No routine follow-up stool cultures are needed if symptoms resolve 1