Corynebacterium infections

The corynebacteria are gram-positive bacilli that are nonspore forming club-shaped rods. The name is derived from the Greek koryne, which stands for club. In a typical Gram stain these bacteria appear as V-in Y-shaped arrangements or in clumps that resemble Chinese letters. Corynebacteria are nonmotile, catalase positive, aerobic, and contain metachromatic granules when stained with methylene blue. They are ubiquitous and can be found on the skin and in the upper respiratory and gastrointestinal tracts. The primary pathogen in this group is Corynebacterium diphtheriae, the etiologic agent of diphtheria. Additional corynebacteria include 45 species, 30 of which on rare occasion cause human disease. The nondiphtheria corynebacteria are increasingly recognized as agents of human disease in immunocompromised patients, and may also, although infrequently, infect healthy adults. Included in this group are C. ulcerans, C. minutissimum, C. pseudodiphtheriticum, C. striatum, C. urealyticum, C. riegelii, and C. glucuronolyticum are uncommon and include respiratory tract infections, ....