Assessing the Safety and Probiotic Characteristics of Lacticaseibacillus rhamnosus X253 via Complete Genome and Phenotype Analysis

Abstract

Lacticaseibacillus rhamnosus is a generalist that can adapt to different ecological niches, serving as a valuable source of probiotics. The genome of L. rhamnosus X253 contains one chromosome and no plasmids, with a size of 2.99 Mb. Both single-copy orthologous gene-based phylogenetic analysis and average nucleotide identity indicated that dairy-derived L. rhamnosus X253 was most closely related to the human-intestine-derived strain L. rhamnosus LOCK908, rather than other dairy strains. The adaptation of L. rhamnosus X253 and the human-intestine-derived strain L. rhamnosus GG to different ecological niches was explained by structural variation analysis and COG annotation. Hemolytic assays, API ZYM assays, and antimicrobial susceptibility tests were performed to validate risk-related sequences such as virulence factors, toxin-encoding genes, and antibiotic-resistance genes in the genomes of L. rhamnosus X253 and GG. The results showed that L. rhamnosus GG was able to use L-fucose, had a higher tolerance to bile salt, and adhered better to CaCo-2 cells. In contrast, L. rhamnosus X253 was capable of utilizing D-lactose, withstood larger quantities of hydrogen peroxide, and possessed excellent antioxidant properties. This study confirmed the safety and probiotic properties of L. rhamnosus X253 via complete genome and phenotype analysis, suggesting its potential as a probiotic.

Genome Sequence and Evaluation of Safety and Probiotic Potential of Lactiplantibacillus plantarum LPJZ-658

“…Therefore, it is necessary to study the distribution of antibiotic-resistance genes in probiotics and the antibiotic resistance pattern of strains [ 61 ]. Similar to commercial probiotic strain LGG, the same resistance gene was identified for L. plantarum LPJZ-658 in the CARD database with coverage >40% and identity >75% [ 48 ]. Furthermore, the antibiotic susceptibility of L. plantarum LPJZ-658 was further investigated, and the results indicated that L. plantarum LPJZ-658 was sensitive or intermediate sensitive to seven antibiotics, including ampicillin, erythromycin, gentamicin, midecamycin, streptomycin, chloramphenicol, and clindamycin.…”

“…The behavior, death, and poisoning of the mice were observed, and the average weight per mouse was calculated once a day. The acid and bile salt tolerance of L. plantarum LPJZ-658 was detected as previously described with some modification [48]. For acid tolerance of L. plantarum LPJZ-658, the active grown cells were harvested, washed with phosphate-buffered saline (PBS) buffer, and resuspended in an equal volume of MRS broth with pH adjusted to 3.0, and then 100 µL aliquots were obtained at different time intervals (0 h and 3 h) for gradient dilution.…”

Lactic Acid Bacteria from Bombyx mori Frass: Probiotic Properties and Antagonistic Activities

“…Only the strains exhibiting gamma haemolysis were considered safe. The selected LAB isolates were then subjected to antibiotic assays, with Staphylococcus aureus serving as a positive control, showing a visible clear zone for beta haemolysis [32].…”

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“…Genetic manipulation is an important tool to study probiotic mechanisms of action e.g., by using isogenic mutant strains, and to potentially create improved strains. However, a scarcity of enough genetic tools out there for a few probiotic species, particularly food-grade systems for Bifidobacteria, and a legal framework for the utilization of genetically manipulated/enhanced organisms limits the analysis progress above 45 . However, It is not common to send genetic constructs to biological repositories.…”