Bacteriological Typing of C. Diphtheriae Strains Recently Isolated in Teheran

Abstract

From a total of 600 nose and throat introduction swabs examined for diphtherie, 200 or 33% were positive. Cultures were carfully classified on the basis of morphological appearance and biochemical characteristics into Gravis, Mitis and Intermedius groups.  A special tellurite serum agar was used for colonial appearance. Neill's broth culture was employed for haemolytic tests. The virulence of each culture was examined in laboratory animals by the agar gel precipitation method of Elek. From 200 cultures tested, 138 or 69% were gravis, 5 or 2.5% were intermedius, and 57 or 28% were mitis. 'I'hre.e strains of gravis type and one strain of mitis type were avirulent