In vitro anaerobic data on ticarcillin/clavulanate. A review of an ongoing survey

Although a number of new antimicrobial agents described as "broad spectrum" have been introduced during the past several years, it should be recognized that each of them has its own unique spectrum of activity, strengths and weaknesses that define its appropriate clinical use. This report reviews the comparative susceptibility data on 495 bacterial isolates obtained from obstetric and gynecologic patients and on 522 Bacteroides fragilis group isolates. Susceptibility testing was conducted with broth microdilution using twofold dilutions of antimicrobials. The overall minimal inhibitory concentrations-90 (MIC90) for the 495 isolates were very low, and few resistant isolates were found. The MIC90 for cefotetan was 16 times greater than that for ticarcillin/clavulanate and ampicillin/sulbactam. Cephalosporins showed good activity against anaerobic cocci but variable activity against anaerobic gram-negative rods. A relatively high percentage of B fragilis group isolates were also resistant to clindamycin. The addition of 2 mg/mL of clavulanate to ticarcillin caused a 4- to 32-fold decrease in the MIC90 for various Bacteroides species. Less than 2% of the strains tested were resistant to clavulanate plus ticarcillin or amoxicillin. These results suggest that monotherapy with such agents could replace combination antibiotic therapy for mixed obstetric and gynecologic infections.