Improved gut microbiome recovery following drug therapy is linked to abundance and replication of probiotic strains

Probiotics have been used for decades to alleviate the negative side-effects of oral antibiotics, but our mechanistic understanding on how they work is so far incomplete. Here, we performed a metagenomic analysis of the fecal microbiota in participants who underwent a 14-d Helicobacter pylori eradication therapy with or without consumption of a multi-strain probiotic intervention (L. paracasei CNCM I-1518, L. paracasei CNCM I-3689, L. rhamnosus CNCM I-3690, and four yogurt strains) in a randomized, double-blinded, controlled clinical trial. Using a strain-level analysis for detection and metagenomic determination of replication rate, ingested strains were detected and replicated transiently in fecal samples and in the gut during and following antibiotic administration. Consumption of the fermented milk product led to a significant, although modest, improvement in the recovery of microbiota composition. Stratification of participants into two groups based on the degree to which their microbiome recovered showed i) a higher fecal abundance of the probiotic L. paracasei and L. rhamnosus strains and ii) an elevated replication rate of one strain (L. paracasei CNCMI-1518) in the recovery group. Collectively, our findings show a small but measurable benefit of a fermented milk product on microbiome recovery after antibiotics, which was linked to the detection and replication of specific probiotic strains. Such functional insight can form the basis for the development of probiotic-based intervention aimed to protect gut microbiome from drug treatments.

[Development of fermented milk product based on mare milk and lactic microorganisms association]

Since ancient times, mare's milk has been widely used by many peoples. Thanks to its unique composition, it is now used in the nutrition of people with allergies to cow's milk, in the technologies of foods for special dietary uses, etc. To expand the range of products with useful properties, it is advisable to develop fermented milk products based on mare's milk. Numerous studies indicate that the use of fermented milk products provides various health benefits. And the use of probiotic cultures in the composition of starter cultures for fermented milk products allows you to add a number of functional properties to the product. However, the only fermented milk product available on the market from mare's milk is koumiss. Therefore, the development of new fermented milk products based on mare's milk is relevant and in demand. The aim of the study was to develop a fermented milk product based on mare's milk using an association consisting of yogurt starter culture and a probiotic strain of L. rhamnosus F. Material and methods. For the development of a fermented milk product based on mare's milk, the yogurt starter STBp (S. thermophilus and L. delbrueckii subsp bulgaricus) and the probiotic culture L. rhamnosus F (GenBank MN994629) from the collection of lactic acid and probiotic microorganisms of VNIMI were chosen. As a basis for the fermented milk product, mare's milk was used with the addition of dry mare's or dry cow's milk, pre-pasteurized at a temperature of 65±1 °C with a holding time of 30 min and cooled to a fermentation temperature of 37±1 °C. In the course of the work, the activity of acid formation during product fermentation, the duration of fermentation and the dynamics of the number of lactic acid bacteria and L. rhamnosus F probiotic strain during fermentation were studied, depending on the ratio of cultures in the ferment, the dose of the ferment introduced and the base for fermentation. The antimicrobial activity of the product was determined by agar well diffusion assay. Results. It was found that L. rhamnosus F has a low acid-forming activity, so the use of a combined starter culture (association) was proposed. It was determined that the addition of cow's milk powder to mare's milk positively affects the activity of acid formation; after 6 hours of fermentation, the pH value varied in the range of 4.6-4.83, and after 8 hours pH was 4.44-4.65. When dry mare's milk was added, the pH value after 8 hours of fermentation was in the range of 4.71-4.98 pH units. The influence of the amount of combined starter culture (association) and its cultures ratio, the duration of fermentation on the content of lactic acid bacteria, including the probiotic strain L. rhamnosus F in the fermented milk product based on mare's milk, was established. The largest amount of L. rhamnosus F was contained in the product fermented by 7% association with the ratio of cultures 1/4 and 1/6 and after 8 h it amounted to 7-9.5×108 CFU/cm3. Conclusion. Summarizing the results of the research, the technology of a fermented milk product based on mare's milk was developed: the amount of starter culture (associations) - 7%, the ratio of cultures - 1 part of the starter culture for yogurt and 6 parts of L. rhamnosus F (1/6), the fermentation temperature - 37±1 °C, the duration of fermentation - 6 hours with the addition of cow's milk powder and 8 hours with the addition of mare's milk powder. The developed fermented milk product has antimicrobial activity against opportunistic and pathogenic microorganisms E. coli ATCC 25922, S. aureus ATCC 6538, S. typhimurium ATCC 14028.