Ampicillin-Based Regimen for Treatment of Chronic Prostatitis Caused by Enterococcus faecalis

Treatment Recommendations

• The American Heart Association recommends ampicillin 2 g IV every 4 hours combined with ceftriaxone 2 g IV every 12 hours for 6 weeks for chronic prostatitis caused by Enterococcus faecalis 1, 2
• The European Society of Cardiology suggests that ampicillin-ceftriaxone combination therapy is effective against E. faecalis strains with and without high-level aminoglycoside resistance (HLAR) 3, 4
• The American College of Cardiology recommends that ampicillin-ceftriaxone regimen has a lower risk of nephrotoxicity compared to aminoglycoside-containing regimens 2
• The European Heart Journal states that the ampicillin-ceftriaxone regimen has similar success rates to aminoglycoside-containing regimens 2

Alternative Regimens

• For aminoglycoside-susceptible strains, the European Society of Cardiology recommends ampicillin 2 g IV every 4 hours and gentamicin 3 mg/kg/day IV or IM in 1 dose for 4-6 weeks 3, 4
• For penicillin-allergic patients, the European Heart Journal suggests vancomycin 30 mg/kg/day IV in 2 doses and gentamicin 3 mg/kg/day IV or IM in 1 dose for 6 weeks 3, 4

Evidence Strength and Considerations

• The American Heart Association reports that the ampicillin-ceftriaxone regimen is supported by strong evidence from multicenter studies showing equivalent efficacy to ampicillin-gentamicin regimens 2, 5
• The European Society of Cardiology notes that the ampicillin-ceftriaxone regimen has significantly lower nephrotoxicity (0% vs 23% with aminoglycoside regimens) 2
• The American College of Cardiology states that the mechanism of action for this double β-lactam combination involves saturation of different penicillin-binding proteins, creating a synergistic effect against enterococci 2, 5

Monitoring and Follow-up

• The European Heart Journal recommends monitoring renal function weekly 3
• The American Heart Association suggests considering potential hypersensitivity reactions to both β-lactams as a potential limitation of this regimen 2

Pitfalls and Caveats

• The American College of Cardiology notes that if the patient develops hypersensitivity to either ampicillin or ceftriaxone, both drugs may need to be discontinued and replaced with vancomycin-gentamicin therapy 1
• The European Society of Cardiology states that for vancomycin-resistant E. faecalis, alternative regimens such as daptomycin plus ampicillin may be considered 3, 6