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.

Abstract

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-25^T and CW-518 belonging to genus Comamonas were isolated by plating dilutions. The polyphasic taxonomy results indicated that strain CW-25^T was a member of Comamonas aquatica, it showed much higher antimicrobials resistance than the closest C. aquatica strains of LMG 2370^T, 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.

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