Evolution of the antimicrobial susceptibility of B. fragilis group at the university hospital of Seville (Spain) between 1977 and 1995

A susceptibility survey of the B. fragilis group divided into three periods was carried out between 1977 and 1995 at the University Hospital of Seville (Spain) using the agar dilution method. No chloramphenicol, imipenem or meropenem-resistant strains were found. Metronidazole-resistant strains (2%) were isolated only in the first period. The most active beta-lactam drugs were piperacillin and ceftizoxime (resistance rate 16%), followed by ticarcillin mezlocillin and azlocillin (25%) and cefotaxime, cefotetam, and cefmetazol (around 40%). All strains tested were resistant to ampicillin and 4% to ampicillin/sulbactam. Cefoxitin resistance increased from 10% in the first two periods to 21% in the third and that of clindamycin from 12% in 1982 to 29% in 1987 and 50% in 1995.