A growing interest in culturable diversity has required microbiologists to think seriously about microbial preservation. In addition to the isolation

Enterococcus faecium though commensal in the human gut, few strains provide a beneficial effect to humans as probiotics while few are responsible for the nosocomial infection. Comparative genomics of E. faecium can decipher the genomic differences responsible for probiotic, pathogenic and non-pathogenic properties. In this study, we compared E. faecium strain 17OM39 with a marketed probiotic, non-pathogenic non-probiotic (NPNP) and pathogenic strains. E. faecium 17OM39 was found to be closely related with marketed probiotic strain T110 based on core genome analysis. Strain 17OM39 was devoid of known vancomycin, tetracycline resistance and functional virulence genes. Moreover, E. faecium 17OM39 genome was found to be more stable due to the absence of frequently found transposable elements. Genes imparting beneficial functional properties were observed to be present in marketed probiotic T110 and 17OM39 strains. Genes associated with colonization and survival within gastrointestinal tract was also detected across all the strains. Beyond shared genetic features; this study particularly identified genes that are responsible for imparting probiotic, non-pathogenic and pathogenic features to the strains of E. faecium. Higher genomic stability, absence of known virulence factors and antibiotic resistance genes and close genomic relatedness with marketed probiotics makes E. faecium 17OM39 a potential probiotic candidate. The work presented here demonstrates that comparative genome analyses can be applied to large numbers of genomes, to find potential probiotic candidates.

A yellow Gram-stain-positive, non-motile, non-endospore -forming, spherical endophytic actinobacterium, designated strain AE-6^T, was isolated from the inner fleshy leaf tissues of Aloe barbadensis (Aloe vera) collected from Pune, Maharashtra, India. Strain AE-6^T grew at high salt concentrations [10 % (w/v) NaCl], temperatures of 15–41 °C and a pH range of 5–12. It showed highest (99.7 %) 16S rRNA gene sequence similarity with Micrococcus yunnanensis YIM 65004^T followed by Micrococcus luteus NCTC 2665^T (99.6 %) and Micrococcus endophyticus YIM 56238^T (99.0 %). Ribosomal protein profiling by MALDI-TOF/MS also showed it was most closely related to M. yunnanensis YIM 65004^T and M. luteus NCTC 2665^T. Like other members of the genus Micrococcus , strain AE-6^T had a high content of branched chain fatty acids (iso-C15 : 0 and anteiso-C15 : 0). MK-8(H₂) and MK-8 were the predominant isoprenoid quinones. Cell wall analysis showed an ‘A2 l-Lys-peptide subunit’ type of peptidoglycan and ribose to be the major cell wall sugar. The DNA G+C content was 70 mol%. Results of DNA–DNA hybridization of AE-6^T with its closest relatives from the genus Micrococcus produced a value of less than 70%. Based on the results of this study, strain AE-6^T could be clearly differentiated from other members of the genus Micrococcus . We propose that it represents a novel species of the genus Micrococcus and suggest the name Micrococcus aloeverae sp. nov., with strain AE-6^T ( = MCC 2184^T = DSM 27472^T) as the type strain of the species.