Description of three new Dryocola species: Dryocola mayonis sp. nov., Dryocola sharpae sp. nov.and Dryocola baronae sp. nov., isolated from human clinical samples

Three previously uncharacterized bacterial species, designated strains BD586^T, BD613^T and BD626^T, isolated from human clinical specimens, were identified at Mayo Clinic, Rochester, Minnesota, USA. Initial identification efforts using matrix-assisted laser desorption ionization-time-of-flight MS and partial 16S rRNA gene sequencing proved inconclusive. Comprehensive analysis involving phenotypic characterization, biochemical assays and whole-genome sequencing was undertaken. The isolates were Gram-negative, motile, facultatively anaerobic rods, occurring singly, in pairs and in short chains; BD613^T additionally formed small aggregates. The isolates tested positive for catalase and negative for oxidase. Their colonies appeared smooth, white, opaque and non-haemolytic. Growth was observed at 35 °C under aerobic, anaerobic and CO₂-enriched conditions, as well as in media with NaCl concentrations up to 10% and at pH 7-9. Phylogenetic relationships were inferred from core gene alignments, average nucleotide identity and digital DNA-DNA hybridization comparisons. Results confirmed the placement of BD586^T, BD613^T and BD626^T within the recently established <i>Dryocola</i> genus, while also indicating their novelty as distinct species. The major cellular fatty acids were C_16:0 and C_17:0 cyclo. Based on these findings, a formal description of three new species, <i>Dryocola mayonis</i> sp. nov. (type strain BD586^T=TSD 474^T, =NCTC 15089^T, =DSM 119465^T), <i>Dryocola sharpae</i> sp. nov. (type strain BD613^T=TSD 475^T, =NCTC 15090^T, =DSM 119466^T) and <i>Dryocola baronae</i> sp. nov. (type strain BD626^T=TSD 476^T, =NCTC 15091^T, =DSM 119479^T), is proposed, and the genus description of <i>Dryocola</i> is emended to refine its genomic, morphological and chemotaxonomic boundaries.