Characteristics of dominant bacteria of colonic lavage fluid in patients with diarrhea-predominant irritable bowel syndrome / 中国医师进修杂志

ABSTRACT

Objective To investigate the characteristics of dominant bacteria of colonic lavage fluid in patients with diarrhea-predominant irritable bowel syndrome (IBS).Methods Forty-six patients with diarrhea-predominant IBS (observation group) and 46 patients with abdominal pain or discomfort who was excluded IBS (control group) from January 2016 to January 2019 in Department of Gastroenterology,Shenzhen Longhua District People's Hospital were selected.During colonoscopy,2 pieces of descending colonic mucosal tissues were taken by forceps,then 4 ml of colonic lavage fluid was collected from the mucosa tissues to extract total DNA,and 10 dominant bacteria were detected by realtime fluorescence quantitative polymerase chain reaction (including Bacteroides,Bacteriodes prevotella,Bifidobacterium,Clostridium,Enteropathogenic Escherichia coli,Dialister pneumosintes,Firmicutes,Faecalibacterium prausnitzii,Salmonella,Lactobacillus,and data were selected for logarithm).The correlation of dominant bacteria between colonic mucosal tissues and colonic lavage fluid was analyzed by Spearman correlation analysis.Results The composition and change of dominant bacteria of colonic mucosal tissues and colonic lavage fluid were basically the same in 2 groups.The numbers of Bacteroides,Bacteriodes prevotella,Clostridium in colonic mucosal tissues and colonic lavage fluid,and the numbers of Faecalibacterium prausnitzii in colonic lavage fluid of observation group were significantly lower than those in the control group (colonic mucosal tissues3.68 ± 0.54 vs.4.34 ± 0.27,4.26 ± 0.28 vs.5.33 ± 0.42,4.46 ± 0.68 vs.4.99 ± 0.61;colonic lavage fluid3.26 ± 0.61 vs.4.09 ± 0.51,3.10 ± 1.42 vs.4.86 ± 1.03,5.24 ± 0.54 vs.5.95 ± 0.51,2.24 ± 1.83 vs.3.24 ± 1.46),and there were statistical differences (P ＜ 0.01 or ＜ 0.05).There was no statistical differences in other dominant bacteria in colonic mucosal tissues and colonic lavage fluid between 2 groups (P ＞ 0.05).Spearman correlation analysisresult showed that the Bifidobacterium,Firmicutes,Faecalibacterium prausnitzii,Lactobacillus colonic mucosal tissues were positively correlated with colonic lavage fluid (r =0.427,0.689,0.577 and 0.369;P =0.041,0.013,0.024 and 0.035),and Enteropathogenic Escherichia coli and Salmonella were negatively correlated with colonic lavage fluid (r =-0.352 and-0.649,P =0.026 and 0.013).Conclusions The composition of dominant bacteria in colonic mucosal tissues and colonic lavage fluid is basically the same,and an imbalance of the microbiota in colonic lavage fluid is found in diarrheapredominant IBS patients.The numbers of Bacteroides,Bacteriodes prevotella,Clostridium and Faecalibacterium prausnitzii significantly decrease.