Howardella ureilytica gen. nov., sp. nov., a Gram-positive, coccoid-shaped bacterium from a sheep rumen

Abstract

An unidentified obligately anaerobic, fastidious, Gram-positive, non-motile, non-spore-forming, non-fermentative coccoid-shaped bacterium (designated strain GPC 589T) was isolated from the rumen fluid of a sheep. The major fatty acid constituents (>5 %) were C16 : 0(29.2 %), C18 : 0(40.7 %) and an unidentified compound (19.7 %) with an equivalent chain-length of 13.523. The G+C content of the DNA was 34 mol%. The organism was strongly ureolytic and generated ATP through the hydrolysis of urea. Comparative 16S rRNA gene sequence analysis demonstrated that strain GPC 589Twas far removed, phylogenetically, from the ruminococci and related Gram-positive anaerobic cocci but exhibited a phylogenetic association withClostridiumrRNA cluster XIVa [as defined by Collins, M. D., Lawson, P. A., Willems, A., Cordoba, J. J., Fernandez-Garayzabal, J., Garcia, P., Cai, J., Hippe, H. & Farrow, J. A. E. (1994).Int J Syst Bacteriol44, 812–826]. Sequence divergence values of 12.5 % or more were observed between strain GPC 589Tand all other recognized species within this and related rRNA clostridial clusters. Phylogenetic analysis showed that strain GPC 589Trepresents a new genus within cluster XIVa. On the basis of both phylogenetic and phenotypic evidence, it is proposed that strain GPC 589Tshould be classified as representing a new genus and novel species,Howardella ureilyticagen. nov., sp. nov. The type strain is strain GPC 589T(=DSM 15118T=JCM 13267T).