Anaerobic bacteria in postsurgical infections: isolation rate and antimicrobial susceptibility.

Three hundred clinical samples, obtained from post-surgical infections, were evaluated. 37% of samples were positive for anaerobes, 99 samples (33%) for aerobes and anaerobes in mixed culture, and 13 (4%) only for anaerobes. One hundred forty-nine anaerobic strains were isolated: Bacteroides and Clostridia occurred most frequently (34% and 23% respectively). Antimicrobial susceptibility of the isolates was tested by means of a commercial broth microdilution method. In addition, the standardized agar dilution method was performed to evaluate the susceptibility to 8 antibiotics of the 51 Bacteroides strains.