Antimicrobial susceptibility of anaerobic bacteria isolated from clinical specimens by using an agar dilution procedure

Abstract

An agar dilution procedure was used to evaluate the antimicrobial susceptibility of 2,126 anaerobic bacteria isolated from a broad spectrum of properly obtained clinical specimens. Significant numbers ofBacteroides species,Fusobacterium species, anaerobic Gram-positive cocci, and anaerobic nonsporeforming Gram-positive bacilli would not grow on Wilkins-Chalgren agar used in the procedure. The failure to obtain growth from theBacteroides species was of special concern since these organisms generally show a higher degree of resistance to antibiotics than the other anaerobic bacteria, which failed to grow or grew poorly on that medium. When compared to other investigations, the data indicated an emerging resistnace to clindamy a forB. thetaiotaomicron andB. distasonis. IndividualClostridium species showed a wide divergence in susceptibility.