Moraxella porci sp. nov., isolated from pigs

Abstract

Nine Gram-negative, catalase- and oxidase-positive, coccus-shaped bacteria were isolated from pigs affected by different pathological processes. Phenotypic and genotypic methods were adopted to determine the relationships of these new isolates to recognized species of the genus Moraxella. Analysis of the 16S rRNA gene sequences demonstrated that the clinical isolates represented a new lineage within the genus Moraxella. The isolates were closely related to Moraxella cuniculi and Moraxella pluranimalium with 16S rRNA gene sequence similarities of 98.1 % and 99.1 %, respectively. The isolates displayed DNA-DNA relative binding ratios of 74 % to each other, but distinctly lower levels of DNA-DNA hybridization were observed with phylogenetically closely related moraxellae (<32 %). The new isolates could be distinguished from all other recognized species of the genus Moraxella by physiological and biochemical tests. On the basis of the phenotypic and molecular data, the nine new isolates from pigs represent a novel species within the genus Moraxella, for which the name Moraxella porci sp. nov. is proposed. The type strain is SN9-4M(T) (=CECT 7294(T)=CCUG 54912(T)).