Lcr35 is a Lactobacillus rhamnosus. Its characterization has been examined in 3 published clinical studies, using phenotypic and genomic methods.
It is of human origin and was isolated in the ‘50s from a healthy child gut. The Lcr35 strain has been used in human medicine for more than 60 years in gastroenterology and 40 years in gynaecology with outstanding safety records (free pharmacovigilance in both therapeutic fields).
It is genetically stable, with no plasmids and no transferable genes for antibio-resistance. The genomic profile of the strain is systematically checked on all our batches.
The phenotype of L. rhamnosus has been characterized using macroscopy, microscopy, catalase presence, homofermentative ability, and carbohydrate metabolism (API 50 CH and VITEK 2) tests. Macroscopically, when grown on Man, Rogosa, Sharpe (MRS) medium, L. rhamnosus surface colonies appear smooth, white, and more or less rounded with regular circular contours. The bottom colonies are lenticular. Microscopically, L. rhamnosus appears as sessile bacilli that are Gram-positive with rounded ends and no spores. L. rhamnosus can be single bacilli, or grouped by two or in short filaments. L. rhamnosus is catalase-negative and does not produce gas after 24 hours. L. rhamnosus has been characterized using the Analytical Profile Index (API) 50 CH test system for carbohydrate metabolism and the VITEK 2 system for identification and antibiotic susceptibility testing.
Lcr35 has been analysed using the above techniques and the results are consistent with the phenotypic profile for L. rhamnosus.
The 16S ribosomal ribonucleic acid (rRNA) gene sequence of Lcr35 was compared to that from strains of L. casei, L. rhamnosus, and L. zeae and the 16S rRNA gene sequences were 99% identical among the strains (see Table 3.3.1-1). These results demonstrate that Lcr35 belongs to the L. casei group, which includes strains of L. casei, L. rhamnosus, and L. zeae.
The rRNA operon of Lcr35 also was sequenced and compared to partial rRNA sequences of various lactic acid bacteria (Coudeyras et al., 2008). The results demonstrated that Lcr35 shared greater than 97% homology with members of the L. casei group.
Multiple alignment comparison of 23S-5S ITS sequences from Lcr35 with those of seven Lactobacillus strains and construction of an Unweighted Pair Group Method with Arithmetic Mean (UPGMA) dendrogram demonstrate that Lcr35 is taxonomically defined at the species level as a member of the L. rhamnosus species (Coudeyras et al., 2008).