Standardized single-disc method for antibiotic susceptibility testing of anaerobic bacteria.

A method was developed for determination of the antibiotic susceptibility of anaerobic bacteria by use of a single-disc diffusion technique and incorporation of the inoculum in pour plates. The method was standardized by correlation of zone diameters with minimal inhibitory concentrations determined in broth. Zone diameters could be used to approximate the minimal inhibitory concentrations of the seven antibiotics tested: ampicillin, bacitracin, carbenicillin, cephalothin, clindamycin, penicillin, and tetracycline.