A Case of Misidentification of Dermabacter hominis as Listeria grayi

Listeria grayi is a catalase-positive, non-spore forming, and glucose-fermenting Gram-positive rod. L. grayi is widely distributed in environments such as soil, water and fresh food. Human infection by L. grayi is very rare, and there have been no cases reported in Korea, and only two cases worldwide. Dermabacter hominis is a relatively new species belonging to the coryneform bacteria and is a component of the normal human skin flora. D. hominis is a non-motile, glucose-fermenting, Gram-positive rod that has similar biochemical characteristics to L. grayi. The authors of the present study report a case initially misidentified as L. grayi via a traditional morphological and biochemical identification method but that was subsequently confirmed as D. hominis using sequence analysis of 16S rRNA. (Korean J Clin Microbiol 2011;14:79-82)