Correlation between Protection against Sepsis by Probiotic Therapy and Stimulation of a Novel Bacterial Phylotype

Abstract

Prophylactic probiotic therapy has shown beneficial effects in an experimental rat model for acute pancreatitis on the health status of the animals. Mechanisms by which probiotic therapy interferes with severity of acute pancreatitis and associated sepsis, however, are poorly understood. The aims of this study were to identify the probiotic-induced changes in the gut microbiota and to correlate these changes to disease outcome. Duodenum and ileum samples were obtained from healthy and diseased rats subjected to pancreatitis for 7 days and prophylactically treated with either a multispecies probiotic mixture or a placebo. Intestinal microbiota was characterized by terminal-restriction fragment length polymorphism (T-RFLP) analyses of PCRamplified 16S rRNA gene fragments. These analyses showed that during acute pancreatitis the host-specific ileal microbiota was replaced by an "acute pancreatitis-associated microbiota." This replacement was not reversed by administration of the probiotic mixture. An increase, however, was observed in the relative abundance of a novel bacterial phylotype most closely related to Clostridium lituseburense and referred to as commensal rat ileum bacterium (CRIB). Specific primers targeting the CRIB 16S rRNA gene sequence were developed to detect this phylotype by quantitative PCR. An ileal abundance of CRIB 16S rRNA genes of more than 7.5% of the total bacterial 16S rRNA gene pool was correlated with reduced duodenal bacterial overgrowth, reduced bacterial translocation to remote organs, improved pancreas pathology, and reduced proinflammatory cytokine levels in plasma. Our current findings and future studies involving this uncharacterized bacterial phylotype will contribute to unraveling one of the potential mechanisms of probiotic therapy.

Impact of Long-Term Proton Pump Inhibitor Therapy on Gut Microbiota in F344 Rats: Pilot Study

“…We hypothesized that long-term administration of PPI is associated with both SIBO and C. difficile infection. Changes of small intestinal microbiota composition are known to be prominent in the terminal ileum,18 and in a study, SIBO and C. difficile colonization as the terminal ileal microbiota has been evaluated 19. To date, microbiota changes in terminal ileum with PPI administration could be summarized as an increase of Firmicutes ( Lactobacillus or Clostridium ) and/or a decrease of Bacteroidetes 9.…”

Peer Review #3 of "Genomic and functional analysis of Romboutsia ilealis CRIBT reveals adaptation to the small intestine (v0.1)"

“…ilealis CRIB T from the small intestine of a rat (Gerritsen et al 2014). In rats, this species was identified to be a dominant member of the ileal microbiota (Gerritsen et al 2011b). Here we applied a holistic systems biology approach, involving several fields of experimental and theoretical biology, to study R. ilealis CRIB T .…”

Peer Review #2 of "Genomic and functional analysis of Romboutsia ilealis CRIBT reveals adaptation to the small intestine (v0.1)"

“…Unfortunately, due to the limited number of available human datasets and the low prevalence of R. ilealis-like 16S rRNA gene sequences in ileal biopsy samples, it was not possible to find positive or negative correlations between prevalence and/or abundance of R. ilealis and specific human diseases. Gerritsen et al (2011b) have shown by 16S rRNA gene sequence-based analysis that R. ilealis CRIB T is a dominant member of the small intestine microbiota in rats, especially in the ileum.…”