Multilaboratory evaluation of the in vitro activity of 13 beta-lactam antibiotics against 1474 clinical isolates of aerobic and anaerobic bacteria.

The in vitro activity of 13 beta-lactam antibiotics against 1474 recent clinical isolates was evaluated in a multilaboratory study. The most active antibiotic tested in this study was imipenem (98.5% of the strains were susceptible), followed by ticarcillin-clavulanate (91.4%), cefoperazone (90.0%), ceftazidime (87.9%), cefotaxime (87.7%), ceftriaxone (87.0%), ceftizoxime (86.3%), cefotetan (78.5%), ampicillin-sulbactam (77.9%), cefoxitin (73.5%), cefuroxime (70.9%), cefonicid (64.5%), and cefazolin (57.9%).