Pathogenic JK group corynebacteria and their similarity to human cutaneous lipophilic diphtheroids

Aerobic diphtheroids from human skin (commonly referred to as lipophilic diphtheroids), pathogenic bacteria of the JK group, and classic species of the genus Corynebacterium were studied for their cellular fatty acids and mycolates, composition of their cell wall peptidoglycans, nutritional requirements, biochemical reactions, and antibiotic sensitivi-ties. Lipophilic diphtheroids and JK strains were catalase positive and contained corynemycolicacid and meso-diaminopimelic acid in their cellwalls, a characteristic shared with all corynebacteria. The lipophilic diphtheroid and JK strains were found to have a strict nutritional requirement for lipid and a similar composition of cellular fatty acid, mycolic acid, and peptidoglycan; they differed only in the multiple antibiotic resistance of the JK strains. Results of the biochemical reactions were inconclusive and did not per-mit grouping of lipophilic diphtheroids or JK with any of the reference strains. The refer-ence strains did not require lipid and contained cellular fatty acids that were clearly dis-tinct from those of the JK strains or lipophilic diphtheroids. These results suggest that JK bacteria are Corynebacterium spp. and may represent resident lipophilic diphtheroids that have acquired antibiotic resistance