Studies on Corynebacterium Diphtheriae

1 Comparative Studies of Corynebacterium Belfanti and Corynebacterium Diphtheriae

Abstract

Bezjak established in 1954 the classification of Corynebacterium (Cory.) belfanti, giving a name as such, by clarifying its biological property not reducing nitrate. Nothing but this property can be usable identifying it from Cory. diphtheriae type mitis, as of the present time. The author adopted this criterion in this paper.
So far, in this country, few attempts have been made to distinguish Cory. belfanti in the case of diphtheria. Therefore, there would have been mixing-up of this type of Corynebacterium in the outcome of surveys of diphtheria epidemics conducted in this country.
In this respect, the author restudied bacteriological properties of 88 strains isolated in other institutes and put under the classification of Cory. diphtheriae. Three standard strains of Cory. belfanti were used contrast. The results were summed up as follows:
Of these 88 strains, 38 turned out to be Cory. diphtheriae type gravis, 45, type mitis and 5, Cory. belfanti. These identifications were done mainly by observing the colonies on Clauberg media, hemolytic property, starch dissolution and nitrate reducing property.
Between Cory. diphtheriae type mitis and cory. belfanti, properties such as diphtheria toxin productivity, drugsensitivity, DNase activities and nitrate reducing activities were compared. No significant differences other than nitrate reducing property were demonstrated between the two.
It is another point of noteworthy that there found one sttain of Cory. diphtheriae type gravis that proved not to reduce nitrate.