[Study of obligate anaerobic bacterial sensitivity to tinidazole and metronidazole (determination of minimal inhibiting concentration--MIC)].

Comparative susceptibility testing of 428 strains of obligate anaerobic bacteria belonging to genera Propionibacterium, Arachnia, Actinomyces, Bacteroides, Prevotella, Porphyromonas, Anaerorhabdus, Fibrobacter, Fusobacterium, Peptostreptococcus and Clostridium to metronidazole and tinidazole was performed. The study of the susceptibility of anaerobic bacteria was carried out by the method of serial dilution in Brucella agar according to Finegold and Sutter (1972). Strains of B. fragilis species, B. fragilis group, other Bacteroides spp.. Fusobacterium spp. and Clostridium spp. were susceptible to both chemotherapeutics in clinically attainable concentrations. Of particular significance is the greater susceptibility of these bacteria to tinidazole. Taking into account this activity, tinidazole is a superior agent in the treatment of anaerobic infections. Both chemotherapeutics were not active against, rarely isolated from severe infections. Gram-positive anaerobic rods from genera Propionibacterium. Actinomyces and Arachnia and were partially active against peptostreptococci.