Gut microbiota and its mysteries.

Gut microbiota are microorganisms that inhabit the gut; they coexist peacefully with the host, thereby contributing to the health and well-being of individuals. Bacteroidetes and Firmicutes largely dominate the gut microbial flora. The intestinal flora promotes intestinal mucosal integrity, provides essential nutrients such as vitamins and enzymes, protects the body against pathogens and produces antimicrobial peptides such as defensins, C-type lectins, cathelicidins, they also play an active role in the innate and adaptive immune system. Gut microbial flora plays an active role in the synthesis of short-chain fatty acids such as butyrate, propionate and acetate. Gut microbiota also plays a significant role in the cognitive and behavioural functions of the host. A balanced gut microbiota shifts to dysbiosis, due to intake of high fat or sugar or other factors like sedentary lifestyle. The dysbiosis of the gut results in increased permeability, endotoxaemic, insulin resistant, systemic inflammation, adiposity and metabolic disorders such as type 2 diabetes mellitus, non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, irritable bowel disorder, colorectal cancer, etc. A prudent lifestyle modification, added on with use of probiotics and prebiotic restore the normal flora of the gut, especially in patients with Clostridium difficle-associated diarrhoea, inflammatory bowel syndrome, liver disease and colon cancer. Faecal microbial transplant is an important therapeutic tool in many illness related with the gut. Thereby, understanding the gut microbial signatures in various diseases yields various novel therapeutic targets. Human gut microbiota has a prognostic, diagnostic and therapeutic potential which is recognised worldwide.

Molecular characterisation and clinical correlates of rotavirus in children and adults in a tertiary care centre, Chennai, South India.

AIMS: This study was undertaken to determine the rate of detection of rotavirus causing diarrhoea among children and adults, identify the common genotypes circulating and determine clinical correlates. SETTINGS AND DESIGN: This is a cross-sectional study in a tertiary care centre. MATERIALS AND METHODS: Stool samples were collected from adults and children, transported on ice, aliquoted and stored at - 80°C. Rotavirus antigen detection enzyme-linked immunosorbent assay was performed on all samples. Representative samples were typed by conventional hemi-nested VP7 and VP4 reverse transcription-polymerase chain reaction. STATISTICAL ANALYSIS USED: Test of proportion, Student's t-test and Chi-square test were used for statistical analysis. RESULTS: A total of 444 stool samples were collected and tested over 14 months. Among these, 116 were paediatric with a rate of positivity of 36.21% and 328 were adults with rate of positivity of 20.73%. Among children under 5 years (n = 90), the rate of positivity was 41.11%. Vesikari scale was used for clinical assessment. The mean ± standard deviation Vesikari score in rotavirus-infected children and rotavirus-uninfected children was 11.2 ± 3.2 and 8.9 ± 3.6, respectively, and the difference was statistically significant. Nineteen samples were genotyped in children < 5 years, 94.7% were of G1P[8] and 5.3% were of G9P[4] genotype. Genotyping of 14 adult samples, G1P[8](85.7%) was found as the predominant genotype, two samples (14.3%) were partially typed (G9PUT and G12PUT). CONCLUSIONS: The rate of positivity of rotavirus in children under 5 years was 41.11%. G1P[8] is the most common strain circulating across all age groups.

Gut Microbiota in Type 2 Diabetes Individuals and Correlation with Monocyte Chemoattractant Protein1 and Interferon Gamma from Patients Attending a Tertiary Care Centre in Chennai, India.

BACKGROUND: Type 2 diabetes mellitus (T2DM) and obesity are associated with changes in gut microbiota and characterized by chronic low-grade inflammation. Monocyte chemoattractant protein-1 (MCP-1) and interferon gamma (IFNγ) are proinflammatory cytokines which play an important role in the development of T2DM. We undertook this study to analyze the gut microbiota of T2DM and nondiabetic subjects and to determine the profile of MCP 1 and IFNγ in the same subjects attending a tertiary care center in Chennai, Tamil Nadu, India. METHODS: The study included 30 subjects with clinical details. Stool and blood samples were collected from all the subjects. DNA was extracted from fecal samples and polymerase chain reaction was done using fusion primers. Metagenomic analysis was performed using ion torrent sequencing. The reads obtained were in FASTA format and reported as operational taxonomic units. Human MCP 1 and IFNγ enzyme linked immunosorbent assay (ELISA) were performed for 23 serum samples. RESULTS: The study consisted of 30 subjects; 17 were T2DM and 13 were nondiabetics. The gut microbiota among T2DM consisted predominantly of Gram negative bacteria; Escherichia and Prevotella, when compared with the nondiabetic group with predominantly Gram positive organisms suchas Faecalibacterium, Eubacterium, and Bifidobacterium. The mean MCP-1 values in the diabetic group were 232.8 pg/ml and in the nondiabetic group 170.84 pg/ml. IFNγ (mean 385.5 pg/ml) was raised in glycated hemoglobin (HbA1c) group of 6.5-7.5% which was statistically significant. Association of Escherichia with T2DM and association of Bifidobacteria in the nondiabetics were also statistically significant. CONCLUSION: Escherichia counts were elevated in T2DM with HbA1c of 6.5-8.5% which was statistically significant suggesting that lipopolysaccharides present in the cell wall of Gram-negative bacteria may be responsible for low-grade inflammation as evidenced by elevated MCP-1 and IFNγ levels in T2DM with the same HbA1c levels.