1. Introduction (1) Diarrhœa is the main problem in patients receiving enteral nutrition (2.5-68%) Consequences are rarely dramatic but are nevertheless relevant (discomfort  life-threatening acidosis) usually leading to a non-optimal refeeding Several factors are responsible for diarrhœa: patient-, nutrition-, and treatment-related

2. Introduction (2) Imbalance of the colonic microflora plays a major role in the pathophysiology of EN diarrhœa  anaerobes (resident flora),  aerobes (potentially harmful)  ANA/AER ratio  short-chain fatty acids (SCFAs) which promote fluid and electrolyte absorption  diarrhœa Schneider et al. Eur J Nutr 2000

3. Introduction (3) Saccharomyces boulardii (Sb), a non-pathogenic yeast, has proven effective in preventing EN-associated diarrhœa in three randomised controlled trials. % days with diarrhœa / days of nutrition % of patients with 1+ days of diarrhœa P=0.007 Bleichner et al. Intensive Care Med 1997

4. Aim of the study Assess the effects of Sb on the intestinal flora of patients on long-term enteral nutrition primary endpoint: fæcal SCFA levels secondary endpoints: fæcal flora

5. Patients & Methods (1) Open-labelled study TEN 10 patients on total enteral nutrition (TEN) for a median 12 months (1-132) (3F, 7M, 59 ± 2 yr, 20 ± 1 kg/m 2 ): Neurological disease (n=3) Head and neck tumour (n=3) Anorexia following GI surgery (n=3) Depression (n=1) HVO 15 healthy volunteers (HVO) (4F, 11M, 32 ± 5 yr, 24 ± 1 kg/m 2 )

6. Patients & Methods (2) Main inclusion criteria: HVO HVO: stable western diet TEN TEN: fibre-free standard formula for 1+ months; energy intake stable for 1+ weeks Main exclusion criteria: Laxative, antibiotic or antifungal drug from 2 weeks before to the end of the study Colon surgery

7. Study design Stool samples analysed in the 2 hours following collection Culture in aerobic and anaerobic media; identification with standard methods and microstrips. SCFAs measured by gas-liquid chromatography Statistical analysis: non-parametric tests Results: mean ± SEM Sb Sb: 0.5 g / 12 h PO or via feeding tube x x stool samples x x D0 D1 D6 D7

8. Results Tolerance HVO HVO: no adverse effect TEN TEN: mild diarrhœa between day 3 and day 6 (no treatment necessary) in one patient

9. Baseline fæcal SCFAs HVO * P=0.02 vs. HVO * mmol / kg

10. Baseline fæcal flora * HVOTEN ANA / AER ratio: HVO: 69.8 ± 0.3TEN: 2.4 ± 0.4 † HVO * P<0.001 † P=0.003 vs. HVO log 10 CFU / g

11. Effects of Sb on fæcal flora ANA / AER ratio: Healthy volunteers Healthy volunteers: 69.8 ± 0.3  60.1 ± 0.4NS TEN patients TEN patients: 2.4 ± 0.4  0.5 ± 0.3NS log 10 CFU / g HVOTEN No difference between time groups BeforeAfter

12. Effects of Sb on fæcal SCFAs (healthy volunteers) No difference between time groups +14% +38% -20%-14% mmol / kg BeforeAfter

13. Effects of Sb on fæcal SCFAs (TEN patients) +40% +26%+58% mmol / kg * P<0.05 † P=0.004 vs. baseline * † * BeforeAfter

14. Conclusion Saccharomyces boulardii increases fæcal SCFA levels (butyrate++) This may explain its preventive effects on EN- induced diarrhœa. Sb does not induce any significant change in the fæcal flora; this may show the limits of conventional bacterial analysis of faeces. This study was supported by a grant from Laboratoires BIOCODEX, Paris.

15. Abstract Rationale: Diarrhœa is a significant problem in patients on total enteral nutrition (TEN). Major changes in their intestinal flora have been reported, with a fall in the anaerobes to aerobes (ANA/AER) ratio. Recent studies suggest that the probiotic yeast Saccharomyces boulardii (Sb) may decrease the incidence of diarrhœa in TEN patients. The aim of this study was to assess the effects of Sb on fæcal flora and short-chain fatty acids (SCFA) in patients on long-term TEN. Methods: 10 patients (3F, 7M, 59±2 y), who had been on TEN for a median of 12 months (1-132), and 15 healthy volunteers (controls) (4F, 11M, 32±5 y) received Sb (0.5 g bid PO) for 6 days. Two stool samples were taken before treatment and on the last 2 days of treatment for culture and bacterial identification and for SCFA measurement (gas-liquid chromatography). Values (M±SEM) were compared using Mann-Whitney and Wilcoxon tests. Results: Before treatment, the ANA/AER ratio was lower in patients compared to controls (2.4±0.4 vs...... 69.8±0.3 mmol/kg, p<0.001). fæcal butyrate levels were lower in patients (10.1±2.9 mmol/kg) than in controls (19.2±3.9 mmol/kg, p=0.02). Treatment with Sb increased total fæcal SCFA levels in TEN patients (150.2±27.2 vs........ 107.5±18.2 mmol/kg, p=0.02) but not in controls (129.0±28.6 vs..... 113.0±15.2 mmol/kg, NS). After treatment with Sb, TEN patients had higher fæcal butyrate (16.0±4.4 vs..... 10.1±2.9 mmol/kg, p=0.004) and propionate (26.2±3.8 vs..... 20.9±3.7 mmol/kg, p=0.04) values. In both groups there were no significant changes in the fæcal flora. Conclusions: Sb-induced increase of fæcal SCFA concentrations (especially butyrate) in TEN patients may at least partly explain the preventive effects of this yeast on TEN-induced diarrhœa. The absence of modification in the fæcal flora calls for the use of more sensitive methods.