Feasibility of Genome-Wide Screening for Biosafety Assessment of Probiotics: A Case Study of Lactobacillus helveticus MTCC 5463.

Recent years have witnessed an explosion in genome sequencing of probiotic strains for accurate identification and characterization. Regulatory bodies are emphasizing on the need for performing phase I safety studies for probiotics. The main hypothesis of this study was to explore the feasibility of using genome databases for safety screening of strains. In this study, we attempted to develop a framework for the safety assessment of a potential probiotic strain, Lactobacillus helveticus MTCC 5463 based on genome mining for genes associated with antibiotic resistance, production of harmful metabolites, and virulence. The sequencing of MTCC 5463 was performed using GS-FLX Titanium reagents. Genes coding for antibiotic resistance and virulence were identified using Antibiotic Resistance Genes Database and Virulence Factors Database. Results indicated that MTCC 5463 carried antibiotic resistance genes associated with beta-lactam and fluoroquinolone. There is no threat of transfer of these genes to host gut commensals because the genes are not plasmid encoded. The presence of genes for adhesion, biofilm, surface proteins, and stress-related proteins provides robustness to the strain. The presence of hemolysin gene in the genome revealed a theoretical risk of virulence. The results of in silico analysis complemented the in vitro studies and human clinical trials, confirming the safety of the probiotic strain. We propose that the safety assessment of probiotic strains administered live at high doses using a genome-wide screening could be an effective and time-saving tool for identifying prognostic biomarkers of biosafety.

Effect of carbon dioxide on sensory attributes, physico-chemical parameters and viability of Probiotic L. helveticus MTCC 5463 in fermented milk.

A carbonated probiotic fermented milk using India's first fully sequenced potential probiotic strain Lactobacillus helveticus MTCC 5463 in a combination with Streptococcus thermophilus MTCC 5460 was prepared and standardized with respect to carbon dioxide pressure, sugar and salt concentrations based on sensory, physico-chemical and microbial parameters. Final optimized product was prepared with 15 % sugar, 0.8 % salt concentration and carbonated at 15 kg cm(-2) pressure which was subsequently subjected to shelf life evaluation for 28 days at 5 ± 1 °C. Even though a significant decrease was observed for overall acceptability, the product was acceptable on 28th day of storage. The titratable acidity, pH and tyrosine value has increased gradually while free fatty acids remained unchanged. The viable lactobaciili and streptococci count decreased from 7.84 to 7.54 and 8.94 to 8.87 log cfu mL(-1) during 28 days of storage, respectively.

Clinical application of probiotics in the treatment of Helicobacter pylori infection--a brief review.

The role of probiotics in the treatment of gastrointestinal infections is increasingly being documented as an alternative or complement to antibiotics, with the potential to decrease the use of antibiotics or reduce their side effects. Although antibiotics-based Helicobacter pylori eradication treatment is 90% effective, it is expensive and causes antibiotic resistance associated with other adverse effects. Probiotics have an in vitro inhibitory effect on H. pylori. Animal studies demonstrated that probiotic treatment is effective in reducing H. pylori-associated gastric inflammation. About 12 human studies investigated the efficacy of combinations of antibiotics and probiotics, whereas 16 studies used probiotic alone as an alternative to antibiotics for the treatment of H. pylori infection. Most of the studies showed an improvement of H. pylori gastritis and decrease in H. pylori colonization after administration of probiotics. However, no study could demonstrate complete eradication of H. pylori infection by probiotic treatment. Probiotic combinations can reduce adverse effects induced by H. pylori eradication treatment and, thus, have beneficial effects in H. pylori-infected individuals. Long-term intakes of products containing probiotic strains may have a favorable effect on H. pylori infection in humans, particularly by reducing the risk of developing disorders associated with high degrees of gastric inflammation.

Whole-genome shotgun sequencing of Lactobacillus rhamnosus MTCC 5462, a strain with probiotic potential.

Lactobacillus rhamnosus MTCC 5462 was isolated from infant gastrointestinal flora. The strain exhibited an ability to reduce cholesterol and stimulate immunity. The strain has exhibited positive results in alleviating gastrointestinal discomfort and good potential as a probiotic. We sequenced the whole genome of the strain and compared it to the published genome sequence of Lactobacillus rhamnosus GG (ATCC 53103).

Whole-genome shotgun sequencing of an Indian-origin Lactobacillus helveticus strain, MTCC 5463, with probiotic potential.

Lactobacillus helveticus MTCC 5463 was isolated from a vaginal swab from a healthy adult female. The strain exhibited potential probiotic properties, with their beneficial role in the gastrointestinal tract and their ability to reduce cholesterol and stimulate immunity. We sequenced the whole genome and compared it with the published genome sequence of Lactobacillus helveticus DPC4571.

Verification of hypocholesterolemic effect of fermented milk on human subjects with different cholesterol levels.

The possible hypocholesterolemic effect of acidophilus milk was evaluated on 27 human subjects having different levels of serum cholesterol, i.e. < 2.0 (group C1), 2.0-2.2 (C2), 2.2-2.5 (C3) and > 2.5 g/L (C4). The acidophilus milk was prepared by fermentation of low-fat milk with Lactobacillus acidophilus and was fed to each volunteer at the rate of 200 mL/d for 20 d. Blood samples from the volunteers were collected and analyzed for lipid profile twice prior to, during and after feeding, keeping a gap of 10 d between two collections. A significant decrease (p < 0.05) in average total cholesterol was found in the C2 and C3 groups, amounting to 21 and 12%, respectively. The average LDL cholesterol decreased in C2, C3 and C4 groups by 0.54, 0.26 and 0.46 g/L, respectively. In the C2 group, the LDL/HDL and total/HDL ratio was also reduced by 1.4 and 1.3, respectively. However, in the C1 group, the average total and LDL cholesterol level did not show any significant change but serum triacylglycerols and VLDL cholesterol showed a significant (p < 0.05) increase of 0.53 and 0.11 g/L, respectively. Regression analysis of the data revealed a square trend in most of the parameters over time period. Overall, the feeding had the best effect in the subjects with lipidemic status of borderline cholesterol level (2.0-2.2 g/L) group.