Expanding the Bacterial Diversity of the Female Urinary Microbiome: Description of Eight New Corynebacterium Species

The genus Corynebacterium is frequently found in the female urinary microbiome (FUM). In-depth characterization of Corynebacterium at the species level has been barely exploited. During ongoing FUM research studies, eight strains (c8Ua_144(T), c8Ua_172(T), c8Ua_174(T), c8Ua_181(T), c9Ua_112(T), c19Ua_109(T), c19Ua_121(T), and c21Ua_68(T)) isolated from urine samples of healthy women or diagnosed with overactive bladder could not be allocated to any valid Corynebacterium species. In this work, we aimed to characterize these strains based on a polyphasic approach. The strains were Gram stain positive, rod to coccoid shaped, nonmotile, catalase positive, and oxidase negative. Phylogenetic analysis based on 16S rRNA and rpoB gene sequences indicated that all strains belonged to the genus Corynebacterium. The average nucleotide identity and digital DNA–DNA hybridization values among the genomes of the above eight strains and closely related type strains of the Corynebacterium genus were <95 (74.1%–93.9%) and <70% (22.2%–56.5%), respectively. Mycolic acids were identified in all strains. MK-8(H2) and/or MK-9(H2) were identified as the major menaquinones. The polar lipids’ pattern mostly consisted of diphosphatidylglycerol, phosphatidylglycerol, and glycophospholipids. The major fatty acid was C(18:1)ω9c. Corynebacterium lehmanniae (c8Ua_144(T) = DSM 113405(T) = CCP 74(T)), Corynebacterium meitnerae (c8Ua_172(T) = DSM 113406(T) = CCP 75(T)), Corynebacterium evansiae (c8Ua_174(T) = DSM 113407(T) = CCP 76(T)), Corynebacterium curieae (c8Ua_181(T) = DSM 113408(T) = CCP 77(T)), Corynebacterium macclintockiae (c9Ua_112(T) = DSM 113409(T) = CCP 78(T)), Corynebacterium hesseae (c19Ua_109(T) = DSM 113410(T)= CCP 79(T)), Corynebacterium marquesiae (c19Ua_121(T) = DSM 113411(T) = CCP 80(T)), and Corynebacterium yonathiae (c21Ua_68(T) = DSM 113412(T) = CCP 81(T)) are proposed. This study evidenced that commonly used methodologies on FUM research presented limited resolution for discriminating Corynebacterium at the species level. Future research studying the biological mechanisms of the new Corynebacterium species here described may shed light on their possible beneficial role for healthy FUM.