Is Antibiotic Susceptibility Testing of Anaerobes Routine?
Most often, antibiotic therapy of anaerobic infection is determined empirically using one of the relatively few drugs available with anaerobic activity (i.e. clindamycin, cefazolin, cefoxitin/cefotetan, metronidazole, penicillin, piperacillin, imipenim) in clinical situations where mixed anaerobic/aerobic infection is suspected. Since the main antibiotic resistance of concern in anaerobes is the production of B-lactamase by specific gram negative organisms such as Bacteroides spp., Prevotella spp. and Porphyromonas spp., these isolates are routinely tested for B-lactamase production when isolated. All anaerobe isolates from sterile fluids/tissues will have susceptibility testing done. Susceptibility testing of anaerobes is otherwise directed by the importance of the isolate(s) given the site/type of infection and the likelihood of antibiotic resistance.
