摘要:Gluconate-fermenting bifidobacteria were isolated from 82% of faecal samples from 44 females. The average bacterial count (log cfu/g faeces) for gluconate-fermenting bifidobacteria was 9.8+-0.5, and the percentage relative to the total bacterial count was 19.1+-14.8. In comparison, the non-fermenting bifidobacteria count was 9.5+-0.7 (p<0.01), corresponding to 12.7+-15.0 (p<0.05) of the total. In the two subjects, who had the coexistence of gluconate-fermenting and nonfermenting bifidobacteria through the gluconic acid administration test, the gluconate-fermenting bifidobacteria increased during gluconate ingestion, whereas the non-fermenting bifidobacteria did not. Gluconate-fermenting bifidobacteria isolated from the human intestinal tract can contain five species in the Bifidobacterium adolescentis group. For the 45 bifidobacteria strains isolated from 10 subjects in the gluconic acid administration test, 16 strains hybridized to the DNA probe of which the target was the base sequences of 16S rRNA gene specific to B. adolescentis . The 45 strains mentioned above were all negative for β-glucuronidase activity, confirming that B. dentium was not isolated.Key words: gluconic acid, gluconate, faecal flora, bifidobacteria