Total artificial nutrition is associated with major changes in the fecal flora

Background Animal studies have demonstrated dramatic changes in the intestinal flora during total enteral (TEN) or parenteral (TPN) nutrition. Aim of the study To assess the impact of TEN and TPN on human intestinal microflora. Methods Eight patients on fiber-free TEN, five patients on TPN, and ten controls were studied. Fecal bacteria were identified and numbered (logCFU/g feces), and fecal short-chain fatty acids (SCFAs) were measured in stool samples, by gas-liquid chromatography. Results In TEN patients, compared to controls (P<0.01), aerobes were increased (8.46+/-0.24) while anaerobes were decreased (5.79+/-0.84). In TPN patients, both aerobes and anaerobes were decreased compared to controls (5.64+/-0.27 and 5.31+/-1.09 respectively, P<0.01). Total SCFAs were lower in TPN patients than in TEN patients (48.3+/-16.6 vs 118.6+/- 24.1 mmol/kg, P<0.05). Conclusions Both TPN and TEN induce modifications in the intestinal microflora. During TPN, a homogeneous decrease occurs in both aerobic and anaerobic bacteria. TEN decreases only anaerobic bacteria, while aerobic bacteria are increased. This imbalance may play a role in the pathophysiology of TEN-induced diarrhea.