The isolates and related reference strains were used to construct the phylogenetic tree (Fig. 1), taking E. coli as outgroups, i.e. the reference sequences.The phylogenetic tree mainly composed of two clusters and five sub-clusters including eleven species of Lactobacillus genus. Cluster I was Lactobacillus casei group which was composed of three sub-clusters: sub-cluster i (Lactobacillus plantarum), sub-cluster ii (Lactobacillus casei) and sub-cluster iii (Lactobacillus fermentum). Cluster II (sub-cluster v) was Lactobacillus helveticus group, which includes sub-cluster vi (Lactobacillus helveticus, Lactobacillus delbrueckii subsp.