Abstract

Metronidazole was found to be active against Bacteroides fragilis strains isolated from human lesions. The minimal inhibitory concentrations (MIC) were from 0·16 to 2·5 μg/ml and the minimal bactericidal concentrations (MBC) were from 0·16 to 2·5 μg/ml; usually the MIC and MBC figures were equivalent. These levels are easily attainable in the serum following normal therapeutic doses. The drug is not toxic and side effects are rare and it would therefore seem highly suitable for treating Bacteroides infections and also may be considered prophylactically in certain situations that are described.