Description of Lactobacillus delbrueckii subsp. indicus, a novel subspecies grouping strains isolated from Indian yogurt.

Four strains isolated from Indian fermented milks were identified as Lactobacillus delbrueckii, however molecular identification and phenotypic traits did not agree with those of recognized subspecies of L. delbrueckii. Techniques applied for a first characterization of strains were ribotyping, IS typing, ARDRA, analysis of expression of genes prtB (encoding for a cell-wall anchored protease) and galT (responsible for the degradation of galactose), determination of the ISL6 in the genomes. Those investigations were integrated with AFLP and RAPD-PCR fingerprints, phylogenetic analysis based on 16S rRNA gene sequences, sequence analysis of two protein-coding genes (recA and hsp60), fermentation profiles and finally, hybridization of total DNA. Data collected indicated that the four strains form a coherent cluster and represent a novel subspecies, for which the name Lactobacillus delbrueckii subsp. indicus subsp. nov. has been validly published.