Isolation and characterization of a novel equol-producing bacterium from human feces.
An equol-producing bacterium was newly isolated from the feces of healthy humans and its morphological and biochemical properties were characterized. The cells were obligate anaerobes. They were non-sporulating, non-motile, gram-positive bacilliform bacteria with a pleomorphic morphology. The strain was catalase-positive, and oxidase-, urease-, and indole-negative. The only other sugar utilized by the strain was glycerin. The strain also degraded gelatin, but not esculin. It was most closely related to Eggerthella hongkongensis HKU10, with 93.3% 16S rDNA nucleotide sequence homology. Based on these features, the isolate was identified as a novel species of the genus Eggerthella. It was named Eggerthella sp. YY7918. Strain YY7918 converted substrates daidzein and dihydrodaidzein into S-equol, but did not convert daidzin, glysitein, genistein, or formononetin into it. An antimicrobial susceptibility assay indicated that strain YY7918 was susceptible to aminoglycoside-, tetracycline-, and new quinolone-antibiotics.
Yokoyama
Shin-ichiro
S
Department of Applied Microbiology, Gifu Prefectural Research Institute for Bioengineering, Gifu, Japan. yokoyama@bio.rd.pref.gifu.jp
Suzuki
Tohru
T
D039903:Actinobacteria / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D060754:Equol; D005243:Feces / Q000382:microbiology*; D006801:Humans; D007529:Isoflavones / Q000096:biosynthesis*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013379:Substrate Specificity
C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D007529:Isoflavones; D012336:RNA, Ribosomal, 16S; D060754:Equol