Bifidobacterium eulemuris sp. nov., isolated from faeces of black lemurs (Eulemur macaco).

Forty-three strains of bifidobacteria were isolated from the faeces of two adult black lemurs, Eulemur macaco. Thirty-four were identified as Bifidobacterium lemurum, recently described in Lemur catta. The nine remaining isolates were Gram-positive-staining, non-spore-forming, fructose-6-phosphate phosphoketolase-positive, microaerophilic, irregular rod-shaped bacteria that often presented Y- or V-shaped cells. Typing techniques revealed that these isolates were nearly identical, and strain LMM_E3T was chosen as a representative and characterized further. Phylogenetic analysis based on 16S rRNA gene sequences clustered this isolate inside the genus Bifidobacterium and showed the highest levels of sequence similarity with B. lemurum DSM 28807T (99.3 %), with Bifidobacterium pullorum LMG 21816T and Bifidobacterium longum subsp. infantis ATCC 15697T (96.4 and 96.3 %, respectively) as the next most similar strains. The hsp60 gene sequence of strain LMM_E3T showed the highest similarity to that of Bifidobacterium stellenboschense DSM 23968T (93.3 %), and 91.0 % similarity to that of the type strain of B. lemurum. DNA-DNA reassociation with the closest neighbour B. lemurum DSM 28807T was found to be 65.4 %. The DNA G+C content was 62.3 mol%. Strain LMM_E3T showed a peptidoglycan structure that has not been detected in bifidobacteria so far: A3α l-Lys-l-Ser-l-Thr-l-Ala. Based on the phylogenetic, genotypic and phenotypic data, strain LMM_E3T represents a novel species within the genus Bifidobacterium, for which the name Bifidobacterium eulemuris sp. nov. is proposed; the type strain is LMM_E3T ( = DSM 100216T = JCM 30801T).

Intestinal microflora and digestive toxicity of irinotecan in mice.

PURPOSE: Delayed diarrhea is the most important side effect of irinotecan. The aim of this study was to investigate the role of intestinal microflora on the induction of systemic and intestinal toxicity and diarrhea, studying germ-free and holoxenic mice i.p. injected with irinotecan. EXPERIMENTAL DESIGN: To evaluate the lethal dose, starting with 100 mg/kg/4 d, we treated the holoxenic mice with 100, 80, and 60 mg/kg/4 d and germ-free mice with 60, 80, 100, and 150 mg/kg/4 d. We recorded the percentage of dead animals, diarrhea, and the epithelial damage to the jejunum, ileum, cecum, and colon at optical and scanning electron microscopy. RESULTS: Germ-free mice were more resistant to irinotecan than the holoxenic group. The lethal dose was between 60 and 80 mg of irinotecan for holoxenic mice and > or =150 mg for the germ-free. The intestinal damage score was higher in holoxenic than germ-free mice at 100 mg and equally diffuse in the small and large bowel. The damage in germ-free mice was less severe (8 of 40 samples) prevailing in the ileum. The differences were significant for all sites (jejunum, P < 0.001; ileum, P = 0.012; cecum, P = 0.001; colon, P < 0.001). No damage was found in germ-free mice at 60 mg. Diarrhea was present in all 100 and 80 mg holoxenic mice and in 19 of 20 cases at 60 mg whereas it was absent in 60 mg or sporadic in 80 and 100 mg germ-free mice. CONCLUSIONS: The intestinal microflora plays a key role in the intestinal toxicity of irinotecan.