Lack of predictability of cefotetan in vitro susceptibility tests against cefotetan-resistant anaerobic bacteria in determining clinical and bacteriologic efficacies.

Interpretive criteria for cefotetan in vitro susceptibility testing appear to be clinically relevant when applied to aerobic bacteria. To determine whether the same was true for anaerobic bacteria, we conducted a retrospective analysis of intraabdominal, gynecologic, and skin and skin structure infections treated with cefotetan. Of the infections, 202 contained at least one anaerobe isolate. Of the 51 patients, 47 (92.9%) from whom one or more cefotetan-resistant anaerobes were isolated were clinically cured or showed improvement. Similarly, cefotetan was efficacious for 95.4% of the patients harboring only cefotetan-susceptible anaerobes. Favorable bacteriologic responses were observed in 94.1% and 97.4% of these patient groups, respectively. The data suggests that the therapeutic utility of cefotetan against anaerobic bacteria cannot be accurately predicted on the basis of in vitro susceptibility test results alone but may be explained by a variety of factors, as discussed in this report.