Suppression of potential pathogens by a defined colonic microflora


Journal Article

Animals acquiring a microflora for the first time do so through the gradual process of ecologic succession. A defined microflora was derived by experimentally simulating this process in gnotobiotic mice. Diverse bacterial species were obtained from ex-germfree mice acquiring a microflora from a conventional mouse. All isolates were characterised to the genus level and polyacrylamide gel electrophoresis (PAGE) was performed on soluble proteins to differentiate isolates at the species or subspecies level. Selected isolates were fully identified. Only 21 per cent of taxa had been previously described. Organisms isolated early in succession tended to ferment more diverse carbohydrates (mean ± SD = 10·2 ± 8·6 carbohydrates per isolate) than organisms found in climax stage mouse flora (5·7 ± 7·0). Bacterial species which predominated during ecologic succession, but which later comprised only a small part of the microflora, were important in simulating certain functions of the entire flora. The defined flora suppressed Escherichia coli to 106·6 colony forming units (CFU) per caecum, a degree of suppression similar to that caused by the entire caecal flora. Pseudomonas aeruginosa was suppressed less by the defined flora (104·4) than by the entire caecal flora (102·0). While Clostridium difficile was suppressed much less by the defined flora (106·6) than by the entire flora (undetectable), animals colonised with the defined flora were protected from colitis when challenged with a pathogenic strain of C. difficile. ©1988 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.

Full Text

Duke Authors

Cited Authors

  • Wilson, K; Moore, L; Patel, M; Permoad, P

Published Date

  • January 1, 1988

Published In

Volume / Issue

  • 1 / 4

Start / End Page

  • 237 - 243

International Standard Serial Number (ISSN)

  • 0891-060X

Digital Object Identifier (DOI)

  • 10.3109/08910608809140528

Citation Source

  • Scopus