Probiotic nomenclature matters redux: confusion on Bifidobacterium longum subsp. infantis taxonomy persists

Fecal bacterial microbiota in constipated patients before and after eight weeks of daily Bifidobacterium infantis 35624 administration

INTRODUCTION AND AIM

In recent years, probiotics have been used in functional gastrointestinal disorders, including chronic constipation (CC). The effect of Bifidobacterium infantis strain 35624 on the gut microbiota of CC patients has not been previously studied. Our aim was to analyze the fecal microbiota of constipated patients, before and after consuming a single-strain probiotic (B. infantis strain 35624).

MATERIALS AND METHODS

We used 16S rRNA gene high-throughput sequencing to analyze the fecal microbiota of female patients (n=13) with CC. Patients were instructed to ingest one capsule of Alflorex® (containing 1×109 CFUs/g B. infantis strain 35624) daily for eight weeks. Fecal samples were obtained at the baseline and end (final) of probiotic administration.

RESULTS

Alpha diversity metrics did not differ between the baseline and final periods. The butyrate producer, Oscillospira, was the taxon most strongly correlated with amplicon sequence variants (R2=0.55, p<0.0001). Except for a few bacterial taxa, there were no significant differences in relative abundance between the baseline and final periods. Beta-diversity measures also showed limited evidence for the differences between the two time periods.

CONCLUSIONS

The results suggest that the fecal bacterial microbiota remains stable in constipated women consuming a single-strain probiotic. Those findings may be helpful in better understanding probiotic functioning in patients with digestive disorders.

A systematic review of the effects of probiotic administration in inflammatory arthritis

OBJECTIVE

To systematically identify and appraise evidence of the formulation specific effects and population specific responses of probiotics in inflammatory arthritis.

METHODS

MEDLINE (PubMed), CINAHL, EMBASE, and SCOPUS databases were searched for studies utilising probiotics in populations with inflammatory arthritis. The Joanna Briggs Institute (JBI) method was used to conduct the systematic review. A single reviewer undertook screening and data extraction. Two independent reviewers assessed the quality of evidence using JBI tools.

RESULTS

The search identified 5876 unique articles, with 154 potentially relevant full text articles retrieved. Twelve studies met the inclusion criteria and were included in the review, of which ten (83%) were randomised control trials (RCT) and two (17%) were quasi-experimental studies. Four studies included a variety of spondyloarthopathies (SpAs) and eight studies focused on rheumatoid arthritis (RA). Probiotics were supplied for a median of 60 days and mode of 56 days across all included studies (range 7-365 days). Overall, 17 different probiotics were supplied in colony forming units (CFU) per 24 hrs ranging from 1 × 10⁸ to 2.25 × 10¹¹. The order of probiotics supplied to the most participants and across the most studies was Lactobacillales. There was no statistical difference in the relative risk (RR) of minor adverse events between probiotic and control groups (RR 1.02, 95% CI 0.69 to 1.51) when including nil event studies. Meta-analysis identified a statistically significant benefit of probiotics on quality of life with a standard mean difference (SMD) of -0.37 (95% CI -0.59,-0.15) with subgroup analysis favouring Lactobacillales-only formulations. Small but statistically significant reductions in pain were identified, with a mean difference (MD) of -8.97 (95% CI-15.38, -2.56) on a 100mm visual analogue scale, independent of formulation. Meta-analysis confirmed the known statistically significant benefit of probiotics on the inflammatory marker C-reactive protein (CRP) concentration MD (mg/L) -2.33 (95% CI -4.26, -0.41), with subgroup analysis demonstrating a greater effect in RA and from combined Bifidobacteriales and Lactobacillales formulations.

CONCLUSION

This review indicates there may be differential benefits to combined formulations of Bifidobacteriales and Lactobacillales compared to purely Lactobacillales formulations, with respect to reducing pain, lowering CRP and improving quality of life. It also suggests variable benefits associated with the type of inflammatory arthritis. Relatively less benefit for lowering CRP was attributed to individuals with SpA compared to individuals with RA. Generalisability of results to clinical practice is limited by the dominant demographic of older individuals with established disease beyond the 'therapeutic window of intervention'. Small but statistically significant benefits require confirmation in clinical studies with greater consideration to potentially confounding factors of age, gender, diet and individual microbial signature.

Probiotic Bifidobacterium strains and galactooligosaccharides improve intestinal barrier function in obese adults but show no synergism when used together as synbiotics

BACKGROUND

One way to improve both the ecological performance and functionality of probiotic bacteria is by combining them with a prebiotic in the form of a synbiotic. However, the degree to which such synbiotic formulations improve probiotic strain functionality in humans has not been tested systematically. Our goal was to use a randomized, double-blind, placebo-controlled, parallel-arm clinical trial in obese humans to compare the ecological and physiological impact of the prebiotic galactooligosaccharides (GOS) and the probiotic strains Bifidobacterium adolescentis IVS-1 (autochthonous and selected via in vivo selection) and Bifidobacterium lactis BB-12 (commercial probiotic allochthonous to the human gut) when used on their own or as synbiotic combinations. After 3 weeks of consumption, strain-specific quantitative real-time PCR and 16S rRNA gene sequencing were performed on fecal samples to assess changes in the microbiota. Intestinal permeability was determined by measuring sugar recovery in urine by GC after consumption of a sugar mixture. Serum-based endotoxin exposure was also assessed.

RESULTS

IVS-1 reached significantly higher cell numbers in fecal samples than BB-12 (P < 0.01) and, remarkably, its administration induced an increase in total bifidobacteria that was comparable to that of GOS. Although GOS showed a clear bifidogenic effect on the resident gut microbiota, both probiotic strains showed only a non-significant trend of higher fecal cell numbers when administered with GOS. Post-aspirin sucralose:lactulose ratios were reduced in groups IVS-1 (P = 0.050), IVS-1 + GOS (P = 0.022), and GOS (P = 0.010), while sucralose excretion was reduced with BB-12 (P = 0.002) and GOS (P = 0.020), indicating improvements in colonic permeability but no synergistic effects. No changes in markers of endotoxemia were observed.

CONCLUSION

This study demonstrated that "autochthony" of the probiotic strain has a larger effect on ecological performance than the provision of a prebiotic substrate, likely due to competitive interactions with members of the resident microbiota. Although the synbiotic combinations tested in this study did not demonstrate functional synergism, our findings clearly showed that the pro- and prebiotic components by themselves improved markers of colonic permeability, providing a rational for their use in pathologies with an underlying leakiness of the gut.