Bacterial Community Analysis on the Skin of Odorrana grahami and Proposal of Comamonas aquatica subsp. aquatica subsp. nov. and Comamonas aquatica subsp. rana subsp. nov.

Several studies indicated that Odorrana grahami (O. grahami) skin contains abundant antimicrobial peptides, and the skin was recognized as hostile habitat for microorganisms. In this study, the microbial community was evaluated by 16S rRNA gene sequencing, and two associated bacterial isolates were obtained and characterized from the skin of O. grahami. Sixteen bacterial genera were identified from the O. grahami skin by uncultured clone sequences. The dominant groups were Comamonas, Bacillus and Morganella, and the genus Comamonas was the most abundant group (41.7% of the total) of the community. Fortunately, strains CW-25T and CW-518 belonging to genus Comamonas were isolated by plating dilutions. The polyphasic taxonomy results indicated that strain CW-25T was a member of Comamonas aquatica, it showed much higher antimicrobials resistance than the closest C. aquatica strains of LMG 2370T, LMG5937 and LMG 6112 isolated from freshwater. Based on the polyphasic taxonomic studies and antimicrobials resistance characteristics, two subspecies of Comamonas aquatica subsp. aquatica nov. and Comamonas aquatica subsp. rana nov. were proposed. The super-antimicrobial resistance endows the strains of Comamonas aquatica subsp. rana inhabit the O. grahami skin, and the primary defense of O. grahami might be composed by the antimicrobial peptides and the native bacteria.

Planococcus ruber sp. nov., isolated from a polluted farmland soil sample.

A pale-red-pigmented bacterial strain, designated CW1T, was isolated from a polluted soil sample in China and was characterized by a polyphasic taxonomic approach. Strain CW1T was Gram-stain-positive (or variable), coccoid, motile by a single polar flagellum and non-spore-forming. Growth was observed at 15-37 °C, but not at 10 °C or 40 °C, at pH 5.0-9.0 and with 0-5 % NaCl (w/v). Phylogenetic analysis showed that strain CW1T belongs to the genus Planococcus. The 16S rRNA gene sequence similarities between CW1T and the four most closely related type strains, Planococcus antarcticus DSM 14505T, Planococcus halocryophilus DSM 24743T, Planomicrobium soli XN13T and Planomicrobium okeanokoites NBRC 12536T were 97.96, 97.83, 97.83 and 97.82 %, respectively. The whole-cell sugars contained galactose, ribose and glucose. The major respiratory quinone was MK-7 followed by MK-8, and the major fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphoglycolipid. The DNA G+C content was 48.6 mol%. The phylogenetic and chemotaxonomic analyses indicated that strain CW1T belongs unanimously to the genus Planococcus. However, DNA-DNA hybridization showed relatively low relatedness of 21.8 % (DSM 14505T) and 19.6 % (DSM 24743T) with the two most closely related strains of the genus Planococcus. Combined with the genotypic and phenotypic analysis, strain CW1T should represent a novel species in the genus Planococcus, for which the name Planococcus ruber sp. nov. is proposed. The type strain is CW1T (=CCTCC AB 207187T=LMG 24442T).