Lactococcus garvieae subsp. bovis subsp. nov., lactic acid bacteria isolated from wild gaur (Bos gaurus) dung, and description of Lactococcus garvieae subsp. garvieae subsp. nov.

A taxonomic investigation was performed on a Gram-stain-positive coccus, designated strain BSN307T, isolated from gaur (Indian bison, Bos gaurus) dung based on phenotypic and molecular approaches. Based on the biochemical tests, cellular morphology and 16S rRNA gene sequence similarity, this strain was found to be a member of the genus Lactococcus and closely related to Lactococcus garvieae ATCC 49156T (99.6 % 16S rRNA gene sequence similarity) and L.actococcus formosensis 516T (99.0 %). However, DNA-DNA hybridization studies showed that the level of relatedness between strain BSN307T and L. garvieae ATCC 49156T was 75.8 %, suggesting that it represented a novel subspecies of L. garvieae. The inability to grow in brain heart infusion (BHI) medium at pH 9.6, in tryptic soy agar (TSA) with 4 % (w/v) NaCl and at 42 °C (MRS agar) clearly differentiated BSN307T from L. garvieae ATCC 49156T. Rep-PCR fingerprint patterns, substantial differences in summed feature 8 (C18 : 1ω7c/C18 : 1ω6c), C19 : 0 cyclo ω8c and C16 : 0 also differentiated strain BSN307T from the reference strain of L. garvieae. Moreover, analysis of the housekeeping genes pheS and rpoA revealed sequence similarities that were at the limit for species differentiation (92.2 and 97.8 %, respectively). Combined genotypic and phenotypic data indicate that strain BSN307T represents a subspecies of L. garvieae for which the name Lactococcus garvieae subsp. bovis subsp. nov. is proposed. The type strain is BSN307T (=DSM 100577 T=MCC 2824T=KCTC 21083T).