The in-vitro susceptibilities of toxigenic strains of Corynebacterium diphtheriae isolated in northwestern Russia and surrounding areas to ten antibiotics.

The in-vitro activities of ten antibiotics against 83 toxigenic strains of Corynebacterium diphtheriae recently isolated in northwestern Russia and surrounding areas were determined by an agar dilution method. All of the strains were susceptible to erythromycin, penicillin, ampicillin, cefuroxime, chloramphenicol, ciprofloxacin, gentamicin and tetracycline. Trimethoprim and rifampicin were each active against 81 isolates, the two strains resistant to the latter agent having been isolated from two members of the same family.