Susceptibility of anaerobic bacteria to sulfamethoxazole/trimethoprim and routine susceptibility testing

The minimal inhibitory concentrations (MICs) of sulfamethoxazole and trimethoprim against 144 strains of obligately anaerobic bacteria were determined on Diagnostic Sensitivity Test agar (Oxoid) or in prereduced Diagnostic Sensitivity Test broth, both supplemented with sodium pyruvate (1 mg/ml), hemin (5 mug/ml), and vitamin K(1) (1 mug/ml). Fifty-eight percent of the strains were susceptible to sulfamethoxazole alone (MIC