Background & aims: Long-term carbohydrate malabsorption in patients with short bowel and colon in continuity (SBC) could result in a more efficient fermentation. The bacterial fermentation capacity in patients with SBC was assessed.
Methods: Eleven fasting patients with SBC ingested 60 g lactulose with 10 g polyethylene glycol. Stool specimens were analyzed. Patients were compared with 8 normal subjects who ingested 60 g lactulose on two occasions, separated by 8 days during which 20 g lactulose was taken twice daily. Moreover, the daily amount of bacteria excreted in stools was measured in 6 patients with SBC and 6 normal subjects.
Results: Despite fast transit time, patients fermented more lactulose and hexoses and had a higher activity of beta-galactosidase in stools than nonadapted normal subjects (P < 0.01); these parameters were roughly similar in patients and adapted normal subjects. The fecal output of short-chain fatty acids was significantly lower in patients than in nonadapted normal subjects (P < 0.03). Patients excreted a significantly greater amount of bacteria in stools than normal subjects (P < 0.05).
Conclusions: In patients with SBC, the capacity of bacterial flora to ferment lactulose and fecal bacterial mass is spontaneously increased, suggesting that hyperfermentation may affect other carbohydrates. Moreover, hyperfermentation is associated with efficient removal of extra short-chain fatty acids from fecal water.