Selective method for identification and quantification of Bifidobacterium animalis subspecies lactis BB-12 (BB-12) from the gastrointestinal tract of healthy volunteers ingesting a combination probiotic of BB-12 and Lactobacillus rhamnosus GG

The global population stru cture of Lacticaseibacillus rhamnosus and its application to an investigation of a rare case of infective endocarditis

BACKGROUND

Lacticaseibacillus (formerly Lactobacillus) rhamnosus is widely used in probiotics or food supplements to promote microbiome health and may also be part of the normal microbiota of the human gastrointestinal tract. However, it rarely also causes invasive or severe infections in patients. It has been postulated that these infections may originate from probiotics or from endogenous commensal reservoirs. In this report, we examine the population structure of Lacticaseibacillus rhamnosus and investigate the utility of using bacterial genomics to identify the source of invasive Lacticaseibacillus infections.

METHODS

Core genome phylogenetic analysis was performed on 602 L. rhamnosus genome sequences from the National Center for Biotechnology public database. This information was then used along with newly generated sequences of L. rhamnosus isolates from yogurt to investigate a fatal case of L. rhamnosus endocarditis.

RESULTS

Phylogenetic analysis demonstrated substantial genetic overlap of L. rhamnosus isolates cultured from food, probiotics, infected patients, and colonized individuals. This was applied to a patient who had both consumed yogurt and developed L. rhamnosus endocarditis to attempt to identify the source of his infection. The sequence of the isolate from the patient's bloodstream differed at only one nucleotide position from one of the yogurt isolates. Both isolates belonged to a clade, identified here as clade YC, composed of mostly gastrointestinal isolates from healthy individuals, some of which also differed by only a single nucleotide change from the patient's isolate.

CONCLUSIONS

As illustrated by this case, whole genome sequencing may be insufficient to reliably determine the source of invasive infections caused by L. rhamnosus.

Human in vivo assessment of the survival and germination of Heyndrickxia coagulans SNZ1969 spores delivered via gummy candies

Confectionary products hold promise as unconventional food carriers for probiotic microorganisms. This study explored the delivery of Heyndrickxia coagulans SNZ1969, a spore-forming probiotic, using gummy candies. In this study, we prepared gummy candies containing bacterial spores with a viable count that remained stable during a 24-month shelf-life period, meeting the label claim of at least one billion CFUs per serving (24 g). Then, we carried out an intervention trial involving 24 healthy adults who consumed one serving per day for two weeks followed by an additional two weeks of follow-up. Fecal samples were collected and analyzed with a protocol that allowed the viable counts of SNZ1969, both in spore and vegetative forms. The obtained results revealed that bacterial spores germinated in all volunteers. SNZ1969 persistence in the gut was monitored for two weeks after the end of gummy candy consumption, indicating its potential for prolonged colonization. These findings highlight the potential of unconventional food carriers for probiotic delivery and suggest that spore-forming probiotics can be metabolically active in the human intestine. These findings provide information for the development of food products containing spore-forming probiotics and their potential benefits in promoting gastrointestinal health.

The Ability of Streptococcus thermophilus BT01 to Modulate Urease Activity in Healthy Subjects' Fecal Samples Depends on the Biomass Production Process

SCOPE

This study evaluates how manufacturing conditions of probiotic biomass production, using two different cryoprotectants, Cryo-A and Cryo-B, can affect Streptococcus thermophilus BT01 in vivo gastrointestinal tract survival and its ability to modulate the level of urease activity in fecal samples of healthy subjects.

METHODS AND RESULTS

A randomized controlled cross-over study is carried out on 20 adult healthy subjects to evaluate total and viable loads, persistence of S. thermophilus BT01, and urease activity in fecal samples. Strain-specific quantification by using developed culture-based method and molecular qPCR tool allows to quantify viable S. thermophilus BT01 strain in 90% of the subjects. The quantification of both total DNA and recovered viable S. thermophilus BT01 in fecal samples does not reveal significant differences between Cryo-A or Cryo-B treated biomass. However, the administration of S. thermophilus BT01 produced with Cryo-A results in a decreased urease activity in fecal samples compared to Cryo-B protected cells.

CONCLUSION

This study i) highlights how the manufacturing conditions can play a role in influencing the probiotic functionality in vivo and ii) represents the first evidence that links S. thermophilus to a specific probiotic mechanism, the reduction of urease activity in fecal samples.

Effects of probiotics on cognitive and emotional functions in healthy older adults: Protocol for a double-blind randomized placebo-controlled crossover trial

Aging is a process that includes changes in cognitive and emotional functions, as well as changes in the diversity and integrity of gut microbiota. Probiotic treatments have recently been studied as a potential new therapeutic approach to alleviate a wide range of problems in other populations; however, clinical studies in older adults remain insufficient and limited. Thus, the aim of this project is to evaluate the efficacy of a multispecies probiotic formulation as a therapeutic strategy for attenuating the emotional and cognitive decline associated with aging in adults over the age of 55. This is a double-blind randomized placebo-controlled crossover trial involving at least 32 older adults and comparing two conditions: (a) probiotic, providing a multispecies probiotic for 10 weeks (Lactobacillus rhamnosus and Bifidobacterium lactis); and (b) placebo, receiving a harmless substance (potato starch). Despite the increasing use of probiotics for the treatment of cognitive and emotional problems, no study has yet focused on this group, to the best of our knowledge. Therapeutic strategies of the kind outlined in this protocol will help to shed light on the current state of knowledge about this topic, as well as promote health programs tailored to this population, which would encourage active aging and healthy lifestyles. Not only do we expect improvements in the emotional dimension in terms of anxiety, stress, depression, and sleep quality, we also expect improvements in the cognitive dimension in terms of attention, memory, and decreased impulsivity.

Fecal Recovery of Probiotics Administered as a Multi-Strain Formulation during Antibiotic Treatment

The present study aimed to investigate whether probiotic recovery is affected when consumed together with antibiotics. Fecal samples were collected from an earlier antibiotic associated diarrhea, randomized, placebo-controlled study with a product consisting of a combination of Lactobacillus acidophilus NCFM, Lactobacillus paracasei Lpc-37, and Bifidobacterium lactis Bi-07, B. lactis Bl-04 at equal numbers and at a total dose of 10¹⁰ CFU. Fecal samples were collected during the screening visit (T0), i.e., at the time of antibiotic prescription, and then on the last day of the antibiotic treatment (T1) as well as seven days after the subject had stopped taking the antibiotic treatment (T2) and at two weeks after completing antibiotic treatment and one week after probiotic/placebo consumption stopped (T3). Samples were analyzed for the presence of the four administered strains. The study was registered at clinicaltrials.gov as NCT01596829. Detection levels of all four strains were significantly increased from T0 to T1 and returned to baseline level from T2 to T3. There were also significantly more subjects with detectable levels of L. paracasei Lpc-37, B. lactis Bi-07, and B. lactis Bl-04 at T1 and T2 compared to T0 and T3, and compared to placebo. Each of the four strains could be detected in the feces of patients apparently unaffected by the simultaneous consumption of antibiotics.

Effect of Cell Concentration on the Persistence in the Human Intestine of Four Probiotic Strains Administered through a Multispecies Formulation

Studies devoted to evaluating the outcome of different doses of probiotics are very limited, especially for multistrain formulations. In this context, we performed an intervention study that aimed to compare the effect of the administration of two doses (7 billion and 70 billion bacterial cells) of a multistrain probiotic formulation on the persistence of the four probiotic strains that were present in the product in the fecal samples collected from healthy subjects. The overall persistence of the probiotic strains was significantly higher for the 70 billion formulation than for the 7 billion formulation. Furthermore, probiotic strains were detected earlier and for longer for the 70 billion formulation compared to those for the 7 billion formulation. All probiotic strains were recovered alive from the 70 billion preparation, whereas recovery was not possible in a few fecal samples upon administration of the 7 billion preparation. In addition, the overall number of viable probiotic cells recovered on day 14 (i.e., the last day of consumption) was significantly higher for the 70 billion formulation than that for the 7 billion formulation. Finally, we found that the viability of the probiotic cells was stable over the course of the trial independent of volunteers' handling, demonstrating good manufacturing of the product. In conclusion, this study demonstrated that strains belonging to different taxa may coexist in the human gastrointestinal tract upon ingestion of a multispecies probiotic formulation. Moreover, this study suggests that higher doses of bacterial cells in probiotic formulations may permit a higher, earlier, and longer recovery of the probiotics in the feces of healthy adults.

Quantitative Recovery of Viable Lactobacillus paracasei CNCM I-1572 (L. casei DG®) After Gastrointestinal Passage in Healthy Adults

Probiotics are live microorganisms, and viability after transit through the gastrointestinal tract (GIT) is considered an inherent property of the health benefits of probiotics. The aim of the present study was to quantify the viable and total loads of Lactobacillus paracasei DG cells after passage through the GIT following the consumption of the probiotic product Enterolactis (L. casei DG®; L. paracasei CNCM I-1572; L. paracasei DG) from drinkable vials by healthy adults. We developed a novel method for discriminating and enumerating culturable L. paracasei DG cells based on the unique sticky, filamentous phenotype of this strain on MRS agar containing vancomycin and kanamycin. The identity of DG was also confirmed with strain-specific primers by colony PCR. This method was used for a recovery study of the DG strain to quantify viable cells in the fecal samples of 20 volunteers during a 1-week probiotic consumption period and a 1-week follow-up. We isolated L. paracasei DG from at least one fecal sample from all the volunteers. The highest concentration of viable DG cells [ranging from 3.6 to 6.7 log₁₀ colony-forming unit (CFU) per gram of feces] in the feces was observed between 4 and 8 days from the beginning of Enterolactis intake and for up to 5 days after cessation of intake. As expected, the total DG count determined by real-time quantitative PCR (qPCR) was mostly higher than the viable DG cells recovered. Viable count experiments, carried out by combining ad hoc culture-based discriminative conditions and strain-specific molecular biological protocols, unambiguously demonstrated that L. paracasei DG can survive gastrointestinal transit in healthy adults when ingested as Enterolactis in drinkable vials containing no less than one billion CFU at the end of shelf life.