Comparative in vitro susceptibilities of 504 bacteremic isolates to ticarcillin plus clavulanic acid and other antimicrobial agents.

A total of 504 clinical bacteremic isolates were tested for susceptibility to ticarcillin-clavulanic acid and 12 other antibiotics. Ticarcillin-clavulanic acid showed superior antibacterial activity compared to penicillin, mezlocillin, piperacillin, ticarcillin, gentamicin, and amikacin against bacteremic isolates of methicillin-susceptible Staphylococcus aureus and Staphylococcus epidermidis. However, ticarcillin-clavulanic acid's activity was inferior to that of vancomycin against methicillin-resistant isolates of S. aureus and S. epidermidis. For Escherichia coli, Klebsiella oxytoca, Proteus mirabilis, Providencia stuartii, and lactose nonfermenting aerobic gram-negative bacilli, the activity of ticarcillin-clavulanic acid surpassed that of mezlocillin, piperacillin, and ticarcillin. Of the antimicrobial agents tested, ticarcillin, piperacillin, ceftazidime, and amikacin were the most active antibiotics against Pseudomonas aeruginosa.