Vibrio casei sp. nov., isolated from the surfaces of two French red smear soft cheeses

Abstract

Three Gram-negative, rod-shaped, catalase- and oxidase-positive, facultatively anaerobic and motile bacteria, strains WS 4538, WS 4539Tand WS 4540, were isolated from the surfaces of two fully ripened French red smear soft cheeses. Based on 16S rRNA gene sequence similarity, all three strains were shown to belong to the genusVibrio. They are most closely related toVibrio rumoiensisS-1T(96.3 % similarity) andVibrio litoralisMANO22DT(95.9 %). DNA–DNA hybridization confirmed that all three isolates belong to the same species and clearly separated strain WS 4539TfromV. rumoiensisDSM 19141T(38–42 % relatedness) andV. litoralisDSM 17657T(28–37 %). In contrast to their nearest relatives, the strains exhibitedβ-galactosidase and aesculin hydrolase activities. A 14 bp insertion in the 16S rRNA gene sequence forms an elongated structure at helix 10 in the rRNA molecule and provides a tool for PCR-based identification of the novel species. Partial sequences of the housekeeping genesatpA,recA,rpoAandpyrHsupported the conclusion that the three isolates constitute a separate species within the genusVibrio. The nameVibrio caseisp. nov. is proposed for the novel taxon. Strain WS 4539T(=DSM 22364T=LMG 25240T; DNA G+C content 41.8 mol%) is the type strain and WS 4540 (=DSM 22378 =LMG 25241) is a reference strain.