Molecular identification of Lactobacillus hilgardii and genetic relatedness with Lactobacillus brevis.

Conventional phenotypic methods lead to misidentification of the lactic acid bacteria Lactobacillus hilgardii and Lactobacillus brevis. Random amplified polymorphic DNA (RAPD) and repetitive element PCR (REP-PCR) techniques were developed for a molecular study of these two species. The taxonomic relationships were confirmed by analysis of the ribosomal operon. Amplified DNA fragments were chosen to isolate L. hilgardii-specific probes. In addition to rapid molecular methods for identification of L. hilgardii, these results convincingly proved that some strains first identified as L. brevis must be reclassified as L. hilgardii. The data clearly showed that these molecular methods are more efficient than phenotypic or biochemical studies for bacterial identification at the species level.