Lactobacillus sobrius sp. nov., abundant in the intestine of weaning piglets

1 Laboratory of Microbiology, Agrotechnology and Food Sciences Group, Wageningen University, Hesselink van Suchtelenweg 4, 6703 CT Wageningen, The Netherlands 2 Istituto Agrario di S. Michele all'Adige, San Michele all'Adige (TN), Italy 3 Department of Microbiology, Faculty of Pharmacy, University of Granada, Spain Correspondence Sergey R. Konstantinov sergey.konstantinov{at}wur.nl To obtain porcine isolates related to Lactobacillus amylovorus , we screened strains from piglet intestine grown on Lactobacillus -specific MRS agar for hybridization to a fluorescent 16S rRNA-targeted DNA probe. Six strains were isolated and further characterized by phenotypic and molecular taxonomic methods. The isolates were Gram-positive, catalase-negative, facultatively anaerobic rods. They had similar phenotypic characteristics and displayed genomic DNA–DNA relatedness values of >78 % to each other, indicating that they belong to a single species. Comparative 16S rRNA gene sequence analysis demonstrated that the novel isolates were members of Lactobacillus rRNA group I, which includes Lactobacillus delbrueckii , the type species of the genus. Based on 16S rRNA gene sequence similarity, Lactobacillus kitasatonis (99 %), Lactobacillus crispatus (98 %) and Lactobacillus amylovorus (97 %) were the nearest relatives of the novel isolates, but their DNA–DNA relatedness was found to be lower than 49 %. One of the isolates, strain OTU171-001 T , was further characterized using physiological and biochemical tests. Together, the results enabled genotypic and phenotypic differentiation of strain OTU171-001 T from the other species that showed 16S rRNA gene sequence similarity values greater than 97 %. Strain OTU171-001 T merits species status and the name Lactobacillus sobrius sp. nov. is proposed. The type strain is OTU171-001 T (=DSM 16698 T =NCCB 100067 T ). Abbreviations: FISH, fluorescence in situ hybridization; FOS, fructooligosaccharides; SBP, sugar beet pulp Published online ahead of print on 16 September 2005 as DOI 10.1099/ijs.0.63508-0. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of Lactobacillus sobrius sp. nov. OTU171-001 T is AY700063 . A figure showing the results of SDS-PAGE analysis and a table detailing the results of DNA–DNA hybridization studies are available as supplementary material in IJSEM Online.