Cellulolytic bacteria in human gut and irritable bowel syndrome

Abstract

Irritable bowel syndrome (IBS) represents one of three major forms of chronic inflammatory bowel disease. The aim of the present study was to investigate the composition and metabolic activities of faecal flora in IBS patients that may take part in initiation and/or maintaining of the disease state. All experiments were designed for three groups of stool donors: healthy individuals, patients with irritable bowel syndrome (IBS) diagnosis before and after treatment by prebiotic preparation Hylak Tropfen Forte. The faecal short chain fatty acid (SCFA) profile of IBS patients was characterized by lower concentration of total SCFA, acetate and propionate (88.15, 60.16 and 18.06 mmol/l, resp.) and by higher concentration of butyrate (9.93 mmol/l). After treatment with Hylak Tropfen Forte, the concentration of total SCFA, acetate and propionate increased (100.66, 75.60 and 18.21 mmol/l, resp.). On the other hand the butyrate concentration decreased (from 9.93 to 6.84 mmol/l). SCFA concentrations in the control group samples for total SCFA, acetate and propionate were as follows: 108.95, 73.26, 26.08 mmol/l. Patients with irritable bowel syndrome diagnosis showed remarkable changes in faecal bacterial population. There were increased numbers of facultative anaerobes and sulphate reducing bacteria. Significantly lower were the counts of cellulolytic bacteria. Total counts of pectinolytic, proteolytic, lactate utilizing and lipolytic bacteria were not significantly different. After treatment with Hylak Tropfen Forte the counts of facultative anaerobes and sulphate reducing bacteria decreased and proportion of cellulolytic bacteria increased significantly and were closer to numbers in faecal samples from healthy persons. This activity could be therefore a possible indicator of irritable bowel syndrome. Faecal bacteria from all three groups of donors were tested for their ability to degrade cellulose, pectin and starch in vitro. Starch degradation was significantly depressed in IBS patients and lower concentrations of acetate, propionate and butyrate were found. Pectin degradation in vitro followed a similar pattern. No degradation of cellulose was found. After treatment with Hylak Tropfen Forte bacterial degradation of these polysaccharides increased but not to the levels of the control group.