Efficacy of sulbactam in an in vitro model of mixed aerobic/anaerobic infections.

Abstract

Bacterial interactions in mixed infections may interfere with antimicrobial therapy. The in-vitro efficacy of ampicillin alone, combination sulbactam/ampicillin, and metronidazole was studied. Strains of Bacteroides fragilis, Escherichia coli, and Enterococcus faecalis, alone and in association, were tested by means of a broth dilution method. Minimal bactericidal concentrations (MBC) of ampicillin for B. fragilis 74 in association with E. coli 68 were up to 16-fold higher than for B. fragilis 74 alone (256 compared to 16 mg/l), but only 2-fold higher for sulbactam (5 mg/l)/ampicillin (0.5 and 0.25 g/l). Association of B. fragilis 45 and E. faecalis 186 increased ampicillin MBC of E. faecalis 186 from 2 to 16 mg/l, but the combination sulbactam/ampicillin restored activity of ampicillin. In association with E. faecalis, metronidazole MBCs of B. fragilis increased up to 64-fold. Strains of E. faecalis and E. coli were able to destroy 10 mg/l metronidazole within 8 to 20 h. The present experiments demonstrated effectiveness of sulbactam/ampicillin to inhibit beta-lactamases of associated pathogens. Destruction of metronidazole by E. faecalis lends additional support to the use of the combination in aerobic/anaerobic infections including E. faecalis.

• Authors: W R Heizmann, F Heilmann, B Egeler, H Werner
• Journal: Infection (Infection) 1990 Mar-Apr Vol. 18 Issue 2 Pg. 117-21 ISSN: 0300-8126 [Print] Germany
• PMID: 2332245 (Publication Type: Journal Article)

Chemical References

• Metronidazole
• Ampicillin
• beta-Lactamases
• Sulbactam

Topics

• Ampicillin (therapeutic use)
• Bacteria, Aerobic (drug effects, growth & development, isolation & purification)
• Bacteria, Anaerobic (drug effects, growth & development, isolation & purification)
• Bacterial Infections (drug therapy, microbiology)
• Drug Therapy, Combination
• Humans
• In Vitro Techniques
• Metronidazole (therapeutic use)
• Microbial Sensitivity Tests
• Sulbactam (pharmacology, therapeutic use)
• beta-Lactamases (biosynthesis)