Acinetobacter rudis sp. nov., isolated from raw milk and raw wastewater

Abstract

Two bacterial strains, G30T and A1PC16, isolated respectively from raw milk and raw wastewater, were characterized using a polyphasic approach. Chemotaxonomic characterization supported the inclusion of these strains in the genus Acinetobacter, with Q-8 and Q-9 as the major respiratory quinones, genomic DNA G+C contents within the range observed for this genus (38–47 mol%) and C16 : 0, C18 : 1ω9c and C16 : 1ω7c/iso-C15 : 0 2-OH as the predominant fatty acids. The observation of 16S rRNA gene sequence similarity lower than 97 % with other Acinetobacter species with validly published names led to the hypothesis that these isolates could represent a novel species. This hypothesis was supported by comparative analysis of partial sequences of the genes rpoB and gyrB, which showed that strains G30T and A1PC16 did not cluster with any species with validly published names, forming a distinct lineage. DNA–DNA hybridizations confirmed that the two strains were members of the same species, which could be distinguished from their congeners by several phenotypic characteristics. On the basis of these arguments, it is proposed that strains G30T and A1PC16 represent a novel species, for which the name Acinetobacter rudis sp. nov. is proposed. The type strain is strain G30T ( = LMG 26107T  = CCUG 57889T  = DSM 24031T  = CECT 7818T).