Temporal temperature gradient gel electrophoresis (TTGE) as a tool for identification of Lactobacillus casei, Lactobacillus paracasei, Lactobacillus zeae and Lactobacillus rhamnosus

Aims: To develop a tool for rapid and inexpensive identification of the Lactobacillus casei complex. Methods and Results: Lactobacillus casei, Lactobacillus paracasei, Lactobacillus zeae and Lactobacillus rhamnosus were identified by PCR-amplification of the segment between the U1 and U2 regions of 16S rDNA (position 8-357, Escherichia coli numbering) and temporal temperature gradient gel electrophoresis (TTGE). Seven tested Lact. paracasei strains were divided into three TTGE-subgroups. Conclusions: TTGE successfully distinguished between the closely-related target species. TTGE is also a powerful method for revealing sequence heterogeneities in the 16S rRNA genes. Significance and Impact of the Study: Due to rapid and easy performance, TTGE of PCR-amplified 16S rDNA fragments will be useful for the identification of extended numbers of isolates.