<i>Lactobacillus rhamnosus</i> R11 Consumed in a Food Supplement Survived Human Digestive Transit without Modifying Microbiota Equilibrium as Assessed by Real-Time Polymerase Chain Reaction

Abstract

The aim of this study was to evaluate the survival of Lactobacillus rhamnosus R11 and Lactobacillus acidophilus R52 in the human digestive tract and their effects on the microbiota homeostasis. We designed an open human trial including 14 healthy volunteers. A 3-week exclusion period of fermented products was followed by a 12-day consumption period of 4 capsules daily containing 2 × 10⁹L. rhamnosus R11 and 1 × 10⁸L. acidophilus R52, and a 12-day wash-out period. The 2 strains and dominant bacterial groups of the microbiota were quantified by real-time polymerase chain reaction. At the end of the capsule consumption period, high levels of L. rhamnosus R11 were detected in faecal samples from all volunteers, reaching a mean value of 7.1 log₁₀ colony-forming unit (CFU) equivalents/g of stool. L. acidophilus R52 was detected in the stools of only 1 volunteer, reaching a maximum level of 6.1 log₁₀ CFU equivalents/g of stool. Dilution plating enumerations performed in parallel provided less consistent and generally lower levels. No significant effect of capsule consumption was observed on microbiota homeostasis for the dominant faecal populations. Mean values of 8.8, 9.2, 9.9 and 10.6 log₁₀ CFU equivalents/g of stool were obtained for the Clostridium coccoides, Bifidobacterium sp., Bacteroides sp. and Clostridium leptum groups, respectively.

Detection and Specific Enumeration of Multi-Strain Probiotics in the Lumen Contents and Mucus Layers of the Rat Intestine After Oral Administration

“…However, in vivo colonisation efficacy has been mainly deduced from analysis of faecal samples [10,32] which fails to provide any information about relative colonisation levels in different segments of the GIT [16]. Accordingly, we obtained mucus and luminal content samples from rat ileum and colon to assess the in vivo distribution and attachment of probiotic cells in the GIT.…”

“…A recent PCR-DGGE study failed to detect bifidobacteria in the caecal contents of rats fed with B. lactis with use of genus-specific primers although a positive result was given by the reference standard [20]. Since PCR-DGGE only allows the identification and quantification of numerically predominant bacterial species, the alternative approach of real-time quantitative PCR (Q-PCR) may be required to evaluate the levels of a subdominant population of ingested probiotic strains in the GIT [1,10].…”

The Firmicutes/Bacteroidetes ratio of the human microbiota changes with age

“…Real-time qPCR was performed using an ABI 7000 Sequence Detection System apparatus with system software version 1.2.3 (Applied-Biosystems) [20,31]. Total numbers of bacteria were inferred from averaged standard curves as described by Lyons et al .…”

“…Primers and probes used in this study were designed based on 16S rRNA sequences. A detailed description can be found in Furet et al [20] and Firmesse et al [31]. …”

Stable Engraftment of Bifidobacterium longum AH1206 in the Human Gut Depends on Individualized Features of the Resident Microbiome

“…However, the degree to which clinical improvements have been causally linked to probiotic-induced microbiota changes has not been established (Sanders et al, 2013). Moreover, most strains show high survival rates in the gastrointestinal tract, but are subsequently detectable for less than 2 weeks following cessation of intake (Alander et al, 2001;Charbonneau et al, 2013;Firmesse et al, 2008;Frese et al, 2012;Malinen et al, 2002;Rattanaprasert et al, 2014;Rochet et al, 2008). In most studies, the introduction of a live microbe did not result in significant alterations of the fecal microbiota (Kristensen et al, 2016).…”