[Use of a DNA-DNA hybridization method for studying Corynebacterium diphtheriae strains].

In addition to traditional tests, a battery of DNA probes was used to characterize 134 toxigenic and 125 nontoxigenic C.diphtheriae strains isolated in Russia in 1986-1989. 2.5% of nontoxigenic strains carried the determinants of both toxin subunits A and B, and 20% possessed at least a fragment of the gene determining toxin synthesis. Optimal conditions of hybridization technology were found. The method may be used as an alternative to traditional techniques in diagnostic studies and screenings.