Probiotic potential of lactic acid bacteria present in home made curd in southern India.

Background & objectives: The human gut microbiota play a significant role in nutritional processes. The concept of probiotics has led to widespread consumption of food preparations containing probiotic microbes such as curd and yogurt. Curd prepared at home is consumed every day in most homes in southern India. In this study the home-made curd was evaluated for lactic acid bacteria (LAB) with probiotic potential. Methods: Fifteen LAB (12 lactobacilli, 1 lactococcus, 2 Lleuconostoc) and one yeast isolated from home-made curd were evaluated for resistance to acid, pepsin, pancreatin and bile salts; antimicrobial resistance; intrinsic antimicrobial activity; adherence to Caco-2 epithelial cells; ability to block pathogen adherence to Caco-2 cells; ability to inhibit interleukin (IL)-8 secretion from HT-29 epithelial cells in response to Vibrio cholerae; and ability to induce anti-inflammatory cytokine expression in THP-1 monocyte cells. Results: Llactobacillus abundance in fermenting curd peaked sharply at 12 h. Nine of the strains survived exposure to acid (pH 3.0) for at least one hour, and all strains survived in the presence of pancreatin or bile salts for 3 h. None showed haemolytic activity. All were resistant to most antimicrobials tested, but were sensitive to imipenem. Most strains inhibited the growth of Salmonella Typhimurium while five inhibited growth of V. cholerae O139. Seven strains showed adherence to Caco-2 cells ranging from 20-104 per cent of adherence of an adherent strain of Escherichia coli, but all inhibited V. cholerae adherence to Caco-2 cells by 20-100 per cent. They inhibited interleukin-8 secretion from HT-29 cells, in response to V. cholerae, by 50-80 per cent. Two strains induced IL-10 and IL-12 messenger ribonucleic acid (mRNA) expression in THP-1 cells. Interpretation & conclusions: LAB in curd had properties consistent with probiotic potential, but these were not consistent across species. LAB abundance in curd increased rapidly at 12 h of fermentation at room temperature and declined thereafter.

Faecal bifidobacteria in Indian neonates & the effect of asymptomatic rotavirus infection during the first month of life.

Background & Objectives: Bifidobacteria colonize the gut after the first week of life and remain an important component of the gut microbiota in infancy. This study was carried out to characterize the diversity and number of bifidobacteria colonizing the gut in Indian neonates and to investigate whether asymptomatic infection with rotavirus in the first month of life affected gut colonization by bidifobacteria. Methods: DNA was isolated from faeces of 14 term-born neonates who were under surveillance for rotavirus infection. Bacterial and bifidobacterial diversity was evaluated by temporal temperature gradient electrophoresis (TTGE) of 16S rDNA amplified using total bacteria and bifidobacteria-specific primers. Real time PCR, targeting 16S rDNA, was used to quantitate faecal bifidobacteria and enterobacteria. Results: TTGE of conserved bacterial 16S rDNA showed 3 dominant bands of which Escherichia coli (family Enterobacteriaceae) and Bifidobacterium (family Bifidobacteriaceae) were constant. TTGE of Bifidobacterium genus-specific DNA showed a single band in all neonates identified by sequencing as Bifidobacterium longum subsp. infantis. Faecal bifidobacterial counts (log10 cfu/g faeces) ranged from 6.1 to 9.3 and enterobacterial counts from 6.3 to 9.5. Neonates without and with rotavirus infection in the first week of life did not show significant differences in the median count of bifidobacteria (log10 count 7.48 vs. 7.41) or enterobacteria (log10 count 8.79 vs. 7.92). Interpretation & Conclusions: B. longum subsp. infantis was the sole bifidobacterial species colonizing the gut of Indian neonates. Asymptomatic rotavirus infection in the first month of life was not associated with alteration in faecal bifidobacteria or enterobacteria.

Common NOD2 mutations are absent in patients with Crohn's disease in India.

BACKGROUND: Crohn's disease is being increasingly diagnosed in the Indian subcontinent. Three apparently common mutations in the NOD2 gene are found in up to 30% of sporadic patients with Crohn's disease in western countries. We examined whether such mutations are also found in Indian patients with Crohn's disease. METHODS: Venous blood was collected from 82 patients (age range: 7-65 years, 53 men) with Crohn's disease and 149 control subjects; DNA was extracted and subjected to polymerase chain reaction using specific primers. The amplified fragments of size 185, 163 and 151 bp for R702W, G908R and 1007fs, respectively, were digested with MspI, HhaI and ApaI, and the restriction pattern noted after electrophoresis. RESULTS: Twenty-eight patients had ileocolonic disease, 26 ileal disease, 20 colonic disease and 8 had disease limited to proximal small bowel or stomach. None of the 82 patients showed any of the three NOD2 mutations. The control subjects (93 men) had a variety of chronic gastrointestinal disorders (ulcerative colitis 52, irritable bowel syndrome 30, intestinal tuberculosis 20, colon cancer 7, miscellaneous 37). None of the control subjects showed a mutation in any of the three NOD2 mutation analyses. CONCLUSION: The three NOD2 gene mutations described above are uncommon in Indian patients with Crohn's disease. This study complements information provided by recent studies on NOD2 mutations in Indians.

Estimation of faecal carriage of Clostridium difficile in patients with ulcerative colitis using real time polymerase chain reaction.

BACKGROUND & OBJECTIVE: Ulcerative colitis (UC) is a disease of unknown aetiology in which exacerbations are sometimes linked to intestinal colonization by toxin-producing Clostridium difficile. We undertook this study to detect and quantitatively assess C. difficile in the stool of patients with UC using real time polymerase chain reaction (RT-PCR), and to compare it with healthy individuals. METHODS: A total of 37 consecutive patients with UC (26 male, mean age 41.3 yr) and 36 healthy adult volunteers (20 male, mean age 36.4), none of whom had received antibiotics within two months prior to faecal collection, were included in the study. Faecal DNA was extracted, quantitative PCR (qPCR) carried out using primers to amplify species-specific segments of 16S rDNA of C. difficile, and expressed as relative fold difference against amplification of highly conserved (universal) segments. Toxins A and B were assayed by ELISA. RESULTS: Quantitative PCR detected C. difficile sensitively, and spiking with increasing numbers of the organism resulted in linear increase in amplification (R(2)=0.974). C. difficile was detected by qPCR in faeces of 20 of 36 healthy volunteers and 34 of 37 patients with UC. Relatively greater amplification of C. difficile (fold difference) was noted in UC compared to controls (P<0.0001). There was no significant difference in C. difficile amplification between patients with proctitis, left sided colitis and pancolitis, or between active and quiescent colitis. Toxin was detected in the faeces of 8 of 37 patients with UC compared to 2 of 36 healthy volunteers. INTERPRETATION & CONCLUSION: Findings of this study showed overgrowth of C. difficile in the stool of Indian patients with UC. However, its relevance to disease pathogenesis and severity in a tropical country like India needs to be investigated further.