Woo TD, Oka K, Takahashi M, Hojo F, Osaki T, Hanawa T, Kurata S, Yonezawa H, Kamiya S. J Med Microbiol. 2011 Nov;60(Pt 11):1617-25. doi: 10.1099/jmm.0.033423-0. Epub 2011 Jun 23.
Synopsis: This study investigated the inhibitory interaction between Clostridium butyricum MIYAIRI 588 (CBM588) and the hospital pathogen Clostridium difficile, which is responsible for a large proportion of antibiotic-associated diarrhea and colitis. CBM588 has previously shown effectiveness against C. difficile in vivo, and here it was found that the toxicity of C. difficile was greatly decreased or absent following in vitro co-culture with CBM588. This effect was dependent on the inoculation ratio and was not accounted for by the growth and mRNA inhibition observed. CBM588 and its cell-free supernatant also had no effect on toxin already secreted into the culture medium, and culture of the two strains separated by a semi-permeable membrane resulted in loss of the inhibition. It was concluded that detoxification of C. difficile probably occurred by inhibition of toxin protein production and that this required close proximity or contact between the two species. The low-pH conditions caused by organic acid secretion were also observed to have inhibitory effects on C. difficile growth, metabolism and toxicity.