Multiplication of orally administered Clostridium butyricum in rats

A mouse monoclonal antibody (MAb) specific to the vegetative cell of Clostridium butyricum strain MIYAIRI 588 (CBM588) was produced by immunisation with whole vegetative cells. This MAb (MAb-MS35) recognised a 35 KDa surface protein on CBM588 and did not cross-react with other intestinal bacteria including 16 strains of C. butyricum. A close correlation was observed between CBM588 vegetative cell counts in rat faeces and enzyme-licked immunosorbent assay (ELISA) values using MAb-MS35. Consequently, this ELISA was used to specifically determine the concentrations of CBM588 in the faeces of rats. The aim of this study was to investigate the fate of CBM588 in the rat gastrointestinal tract after a single oral administration. CBM588 spores were administered intragastrically at 10(7) cells per rat, and the faeces of each rat were collected twice daily. CBM588 vegetative cells were detected in the faeces for 3 d after administration. Total recovery of CBM588 vegetative cells from faeces were three to six times the spore dose. In addition, CBM588 vegetative cells were observed microscopically using faecal smears and an immunogold-silver staining method with MAb-MS35. These findings indicate that CBM588 spores germinate and the vegetative cells multiply in the gastrointestinal tract of rats.