The first comparative metagenomic analysis of diarrheal and non-diarrheal gut microbiome leading to the identification of prospective prognostic markers and probiotics to protect from diarrhea: A Brief Report

Introduction: Diarrhea is a leading contributor of mortality. Its disease burden can be assuaged using enhanced prognostics and therapeutics. A cross-sectional gut microbiome analysis  of  non-diarrheal  and   diarrheal  fecal  samples was conducted to meet the goals of the Global Action Plan for Pneumonia and Diarrhea. Hypothesis: Next-generation Sequencing as a tool for epidemiological surveillance helps in the comparison of structural diversity of the gut microbiome of diarrheal and non-diarrheal samples and can identify prognostic and therapeutic candidates. Aim: The pilot study was designed to identify taxa that are enriched in non-diarrheal samples and to predict gut microbial interactions. Methodology: 16SrRNA amplicon sequencing  and  analysis  were deployed for taxonomic  profiling  and  abundance  interpretation  of  OTUs (Operational Taxonomic Units). Results: The findings suggested significant  differences  in structural composition between  the  two  groups. Firmicutes was the  most  abundant  phylum in most samples. B/F ratio was consistently <1 in all diarrheal samples. Proteobacteria  was    more  abundant  in    diarrheal  samples.  Prevotellaceae  was  the  most  abundant  family  in  non-diarrheal  samples.  Streptococcaceae  was  the  most  abundant  family  in  60%  diarrheal  samples.Where  Streptococcaceae  was  suppressed,  Bacteroideaceae  and  Nocardeaceae  were  the  most  abundant.    In  non-diarrheal  samples  where  Bifidobacteriaceae  was  the  most  abundant  other  families  were significantly low.  A  negative  correlation  was  observed  between  Prevotellaceae  and  Bacteroideaceae  in    non-diarrheal  samples.  Prevotella  copri  was  the  most  abundant  species  in  70%  non-diarrheal  samples  and  was  significantly  suppressed  in  diarrheal  samples.  Proteus  mirabilis  was  identified  in  all  the  non-diarrheal  samples  and  were  absent in  diarrheal  samples.  Conclusion: The OTUs  associated  with  diarrheal  dysbiosis  can  serve  as  prognostic  markers.  This is the first report on the comparative analysis of diarrheal and non-diarrheal microbiome.  The study addressed  gut microbiome dysbiosis from the context that can lead to the development of prognostic markers and probiotics for protecting the endemic population from diarrhea and help in reaching Sustainable Development Goals 2 and 3.