title: Multilocus sequence typing reveals a novel subspeciation of Lactobacillus delbrueckii.
abstract: Currently, the species Lactobacillus delbrueckii is divided into four subspecies, L. delbrueckii subsp. delbrueckii, L. delbrueckii subsp. bulgaricus, L. delbrueckii subsp. indicus and L. delbrueckii subsp. lactis. These classifications were based mainly on phenotypic identification methods and few studies have used genotypic identification methods. As a result, these subspecies have not yet been reliably delineated. In this study, the four subspecies of L. delbrueckii were discriminated by phenotype and by genotypic identification [amplified-fragment length polymorphism (AFLP) and multilocus sequence typing (MLST)] methods. The MLST method developed here was based on the analysis of seven housekeeping genes (fusA, gyrB, hsp60, ileS, pyrG, recA and recG). The MLST method had good discriminatory ability: the 41 strains of L. delbrueckii examined were divided into 34 sequence types, with 29 sequence types represented by only a single strain. The sequence types were divided into eight groups. These groups could be discriminated as representing different subspecies. The results of the AFLP and MLST analyses were consistent. The type strain of L. delbrueckii subsp. delbrueckii, YIT 0080(T), was clearly discriminated from the other strains currently classified as members of this subspecies, which were located close to strains of L. delbrueckii subsp. lactis. The MLST scheme developed in this study should be a useful tool for the identification of strains of L. delbrueckii to the subspecies level.
authors.affiliation: Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi, Tokyo 186-8650, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Tanigawa
authors.affiliation: Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi, Tokyo 186-8650, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Watanabe
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques / Q000379:methods*; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D005838:Genotype; D048668:Lactobacillus delbrueckii / Q000145:classification* / Q000235:genetics*; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing / Q000379:methods*; D010641:Phenotype; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial