Megasphaera lornae sp. nov., Megasphaera hutchinsoni sp. nov., and Megasphaera vaginalis sp. nov.: novel bacteria isolated from the female genital tract

Six strictly anaerobic Gram-negative bacteria representing three novel species were isolated from the female reproductive tract. The proposed type strains for each species were designated UPII 199-6(T), KA00182(T) and BV3C16-1(T). Phylogenetic analy-ses based on 16S rRNA gene sequencing indicated that the bacterial isolates were members of the genus Megasphaera. UPII 199-6T and KA00182(T) had 16S rRNA gene sequence identities of 99.9 % with 16S rRNA clone sequences previously amplified from the human vagina designated as Megasphaera type 1 and Megasphaera type 2, members of the human vaginal microbiota associated with bacterial vaginosis, preterm birth and HIV acquisition. UPII 199-6T exhibited sequence identities ranging from 92.9 to 93.6 % with validly named Megasphaera isolates and KA00182(T) had 16S rRNA gene sequence identities ranging from 92.6?94.2 %. BV3C16-1Twas most closely related to Megasphaera cerevisiae with a 16S rRNA gene sequence identity of 95.4 %. Cells were coccoid or diplococcoid, non-motile and did not form spores. Genital tract isolates metabolized organic acids but were asaccharolytic. The isolates also metabolized amino acids. The DNA G+C content for the genome sequences of UPII 199-6T, KA00182T and BV3C16-1T were 46.4, 38.9 and 49.8 mol%, respectively. Digital DNA?DNA hybridization and average nucleotide identity between the genital tract isolates and other validly named Megasphaera species suggest that each isolate type repre-sents a new species. The major fatty acid methyl esters include the following. C12.0, C16.0, C16. 0 dimethyl acetal (DMA) and summed feature 5 (C15.0 DMA and/or C14. 0 3 -OH) in UPII 199-6(T); C16. 0 and C16.1cis 9 in KA00182(T); C12.0; C14. 0 3 -OH; and summed feature 5 in BV3C16-1(T). The isolates produced butyrate, isobutyrate, and isovalerate but there were specific differences including produc-tion of formate and propionate. Together, these data indicate that UPII 199-6(T), KA00182T and BV3C16-1(T) represent novel species within the genus Megasphaera. We propose the following names. Megasphaera lornae sp. nov. for UPII 199-6T representing the type strain of this species (=DSM 111201(T)=ATCC TSD-20(5)T), Megasphaera hutchinsoni sp. nov. for KA00182T representing the type strain of this species (=DSM 111202(T)=ATCC TSD-206(T)) and Megasphaera vaginalis sp. nov. for BV3C16-1(T) representing the type strain of this species (=DSM 111203T=ATCC TSD-207T).