Taxonomic and Strain-Specific Identification of the Probiotic Strain Lactobacillus rhamnosus 35 within the Lactobacillus casei Group

Abstract

Lactobacilli are lactic acid bacteria that are widespread in the environment, including the human diet and gastrointestinal tract. Some Lactobacillus strains are regarded as probiotics because they exhibit beneficial health effects on their host. In this study, the long-used probiotic strain Lactobacillus rhamnosus 35 was characterized at a molecular level and compared with seven reference strains from the Lactobacillus casei group. Analysis of rrn operon sequences confirmed that L. rhamnosus 35 indeed belongs to the L. rhamnosus species, and both temporal temperature gradient gel electrophoresis and ribotyping showed that it is closer to the probiotic strain L. rhamnosus ATCC 53103 (also known as L. rhamnosus GG) than to the species type strain. In addition, L. casei ATCC 334 gathered in a coherent cluster with L. paracasei type strains, unlike L. casei ATCC 393, which was closer to L. zeae; this is evidence of the lack of relatedness between the two L. casei strains. Further characterization of the eight strains by pulsed-field gel electrophoresis repetitive DNA element-based PCR identified distinct patterns for each strain, whereas two isolates of L. rhamnosus 35 sampled 40 years apart could not be distinguished. By subtractive hybridization using the L. rhamnosus GG genome as a driver, we were able to isolate five L. rhamnosus 35-specific sequences, including two phage-related ones. The primer pairs designed to amplify these five regions allowed us to develop rapid and highly specific PCR-based identification methods for the probiotic strain L. rhamnosus 35.

Lactobacillus rhamnosus Meningitis following Recurrent Episodes of Bacteremia in a Child Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

“…The patient received no probiotic during his hospital stay. Moreover, the PFGE pattern clearly differed from those observed for both probiotics L. rhamnosus Lcr35 and L. rhamnosus ATCC 53103, so-called L. rhamnosus GG (9). Colonoscopy was performed on day 101 and revealed no anomaly that could have favored the translocation of the Lactobacillus.…”

Naturally occurring genetic markers in lactobacilli and their use to verify the authenticity of Swiss Emmental PDO cheese

“…Tilsala-Timisjarvi and Alatossava [21] used the randomly amplified polymorphic DNA (RAPD) technique to produce potential strain-specific markers for a probiotic L. rhamnosus strain and obtained a specific sequence that showed a significant similarity to transposases of other lactic acid bacteria. Similarly, Coudeyras et al [3] developed a strain-specific identification for a probiotic L. rhamnosus strain using subtractive hybridization and obtained with this method among four other specific sequences a sequence that corresponded to an IS. Our approach to developing strain-specific PCR is particularly efficient when a complete genome sequence of the species or of related organisms is available and it should also be applicable to other types of bacteria which need to be traced over relatively short time periods.…”

Letter: identication of probiotics by specific strain name

“…[4][5][6] This is even more important in the case of LGG. Kankainen et al sequenced and compared the genomes of LGG and a different L. rhamnosus and found that there is a 98% average identity (the same between man and a monkey), however, in the 2% of diversity resides a set of genes (spaCBA) encoding three pilin proteins and another gene responsible for the assembly of pilus structures important for colonisation and host interaction.…”