Enterococcus bulliens sp. nov., a novel lactic acid bacterium isolated from camel milk

Four lactic acid bacteria isolates obtained from fresh dromedary camel milk produced in Dakhla, a city in southern Morocco, were characterised in order to determine their taxonomic position. The four isolates had highly similar MALDI-TOF MS and RAPD fingerprints and identical 16S rRNA gene sequences. Comparative sequence analysis revealed that the 16S rRNA gene sequence of the four isolates was most similar to that of Enterococcus sulfureus ATCC 49903T and Enterococcus italicus DSM 15952T (99.33 and 98.59 % similarity, respectively). However, sequence analysis of the phenylalanyl-tRNA synthase (pheS), RNA polymerase (rpoA) and ATP synthase (atpA) genes revealed that the taxon represented by strain LMG 28766T was well separated from E. sulfureus LMG 13084T and E. italicus LMG 22039T, which was further confirmed by DNA-DNA hybridization values that were clearly below the species demarcation threshold. The novel taxon was easily differentiated from its nearest neighbour species through sequence analysis of protein encoding genes, MALDI-TOF mass spectrometry and multiple biochemical tests, but had a similar percentage G+C content of about 39 %. We therefore propose to formally classify these isolates as Enterococcus bulliens sp. nov., with LMG 28766T (=CCMM B1177T) as the type strain.