Identification of Lactobacillus species of human origin by a commercial kit, API50CHL.

The efficacy of a biochemical kit, API50CHL kit, for identification of intestinal and vaginal lactobacilli from humans was evaluated by comparing with the results of DNA-DNA hybridization assay. The results showed that in total only 52 of the 172 strains (30.2%) tested were identified correctly by the kit at species level. Especially all strains of some species, such as Lactobacillus gasseri and Lactobacillus crispatus, were misidentified as Lactobacillus acidophilus by the kit. However, the kit was found to be reliable for identification of Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, and Lactobacillus salivarius. This suggests that the exact identification of Lactobacillus isolates from human stool and vaginal specimens by API50CHL kit is difficult without the support of modern genotypic technique.