Nocardia huaxiensis sp. nov., an actinomycete isolated from human skin.

Abstract

A novel actinomycete, designated as strain WCH-YHL-001T, was isolated from skin biopsy specimens of a patient at West China Hospital, Chengdu, Sichuan Province, PR China. The cells were Gram-positive, aerobic, heterotrophic and non-motile. They formed an extensive substrate with short aerial mycelia, whose branches fragmented into rod-shaped elements. Growth occurred at 10-40 °C, pH 5.0-12.0 and with NaCl concentrations of 0-4.0 % (w/v). The major cellular fatty acids of strain WCH-YHL-001T were C16 : 0, C18 : 1 ω9c, C18 : 0 10-methyl and summed feature 3. The predominant respiratory quinone was MK-8 (H4ω-cycl). The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol mannoside, unknown phospholipids and unidentified glycolipids. The diagnostic diamino acid of peptidoglycan was meso-diaminopimelic acid. The whole-cell sugar pattern consisted of arabinose and glucose. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain WCH-YHL-001T belonged to the genus Nocardia. The average nucleotide identity (ANI) and in silico DNA-DNA hybridization (isDDH) values between strain WCH-YHL-001T and type strains of Nocardia species were lower than the cut-offs (≥95-96 % for ANI and ≥70 % for isDDH) required to define a bacterial species. The genomic DNA G+C content was 67.8 mol%. Phylogenetic, physiological and chemotaxonomic data suggested that strain WCH-YHL-001T represented a novel species of the genus Nocardia, for which the name Nocardia huaxiensis sp. nov. is proposed, with the type strain WCH-YHL-001T (=GDMCC 4.181T=JCM 34475 T=NBRC 114973T).