Antimicrobial susceptibility of anaerobic and aerobic bacteria isolated from patients with mixed infections in Nicaragua.
The agar dilution method was used to test the activity of ampicillin, benzylpenicillin, cefoxitin, imipenem, clindamycin, metronidazole, chloramphenicol, gentamicin, methicillin and vancomycin against 241 anaerobic and 227 aerobic bacteria isolated from 136 patients with intraabdominal infections and 49 with nonintraabdominal infections. Beta-lactamase production was tested in all strains. Overall, imipenem, metronidazole and chloramphenicol were the most active antimicrobial agents against anaerobic bacteria followed by clindamycin. Only the Bacteroides fragilis group was shown to be less susceptible to clindamycin (MIC90 8 mg/l). Ampicillin and cefoxitin were the least active beta-lactam antibiotics against the most common isolated B. fragilis group strains (MIC(90) >1024 and 64 mg/l, respectively) and against Escherichia coli strains (MIC(90) >1024 and >1024 mg/l, respectively). Chloramphenicol showed low activity against the Gram-negative aerobic bacteria, while gentamicin had good activity against the aerobic bacteria tested, except for E. coli and Pseudomonas. Among the Gram-positive aerobic and anaerobic bacteria tested, Staphylococcus aureus was shown to be less susceptible to beta-lactam antibiotics (29&#37; were methicillin resistant). No vancomycin-resistant S. aureus strains were found. A good correlation between beta-lactamase production and beta-lactam resistance was observed.
Cáceres
M
M
Department of Microbiology, National Autonomous University of León, Nicaragua.
Carrera
E
E
Palma
A
A
Berrios
G
G
Weintraub
A
A
Nord
C E
CE
D001420:Bacteria, Aerobic / Q000187:drug effects*; D001421:Bacteria, Anaerobic / Q000187:drug effects*; D001424:Bacterial Infections / Q000188:drug therapy*; D004352:Drug Resistance, Microbial; D006801:Humans; D008826:Microbial Sensitivity Tests; D009527:Nicaragua