Identification of "Micrococcus candidus" ATCC 14852 as a strain of Staphylococcus epidermidis and of "Micrococcus caseolyticus" ATCC 13548 and Micrococcus varians ATCC 29750 as Members of a New Species, Staphylococcus caseolyticus

Abstract

Comparative chemical, biochemical, and in vitro genetic analyses of “Micrococcus candidus” ATCC 14852, “M. caseolyticus” ATCC 13548, and M. varians ATCC 29750 have demonstrated that these strains were misidentified and that they should be assigned to the genus Staphylococcus. (Names in quotation marks are not on the Approved Lists of Bacterial Names, have not been validly published since 1 January 1980, and therefore do not have nomenclatural standing.) Deoxyribonucleic acid (DNA)-DNA-hybridization experiments and other physiological and biochemical data indicated that “M. candidus” ATCC 14852 is a strain of Staphylococcus epidermidis. High DNA homology values also revealed that “M. caseolyticus” ATCC 13548 and M. varians ATCC 29750 are related to each other at the species level. Although they differ from most staphylococci in their production of class II fructose-1,6-diphosphate aldolase and in their cytochrome composition, they are, on the basis of their cell wall compositions, the low guanine + cytosine contents of their DNAs, and the results of DNA-ribosomal ribonucleic acid hybridization studies, genuine members of the genus Staphylococcus. DNA-DNA hybridization experiments demonstrated that they are not closely related to any of the known Staphylococcus species. It is proposed that these organisms represent a new species, namely, S. caseolyticus. Strain ATCC 13548 is the type strain.