Modified culture technique for Corynebacterium diphtheriae isolation from desiccated swabs.

Corynebacterium diphtheriae was isolated from pyoderma and ulcerative skin lesions with a modified delayed culture procedure as late as 9 weeks after field collection of silica gel-desiccated swabs. Biotypes gravis and mitis were identified. Most isolates were nontoxigenic. Todd-Hewitt broth enrichment enhanced recovery of C. diphtheriae by 70%.