Differentiation of Corynebacterium amycolatum, C. minutissimum, and C. striatum by Carbon Substrate Assimilation Tests

We tested the carbon substrate assimilation patterns of 40 Corynebacterium amycolatum strains, 19 C. minutissimum strains, 50 C. striatum strains, and 1 C. xerosis strain with the Biotype 100 system (bioMérieux, Marcy-l’Étoile, France). Twelve carbon substrates of 99 allowed discrimination among the species tested. Additionally, assimilation of 3 of these 12 carbon substrates (maltose, N-acetyl-d-glucosamine, and phenylacetate) was tested with the API 20 NE identification system (bioMérieux). Since concordant results were observed with the two systems for these three carbon substrates, either identification system can be used as a supplementary tool to achieve phenotypic differential identification of C. amycolatum, C. minutissimum, and C. striatum in the clinical microbiology laboratory.