Hostname: page-component-cc8bf7c57-5wl6q Total loading time: 0 Render date: 2024-12-09T08:30:49.605Z Has data issue: false hasContentIssue false

Prevalence of enteric bacteria that inhibit growth of enterohaemorrhagic Escherichia coli O157 in humans

Published online by Cambridge University Press:  02 June 2006

H. TOSHIMA
Affiliation:
Graduate School of Human Life Science, Osaka City University, Japan
M. HACHIO
Affiliation:
Graduate School of Human Life Science, Osaka City University, Japan
Y. IKEMOTO
Affiliation:
Graduate School of Human Life Science, Osaka City University, Japan
J. OGASAWARA
Affiliation:
Department of Microbiology, Osaka City Institute of Public Health and Environmental Sciences, Japan
A. HASE
Affiliation:
Department of Microbiology, Osaka City Institute of Public Health and Environmental Sciences, Japan
K. TAKAHASHI
Affiliation:
Urban Living and Health Association, Japan
H. MASAKI
Affiliation:
Department of Biotechnology, The University of Tokyo, Japan
Y. NISHIKAWA
Affiliation:
Graduate School of Human Life Science, Osaka City University, Japan
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Enterohaemorrhagic Escherichia coli O157 (O157) is infectious to humans, particularly children, at very low doses and causes not only haemorrhagic colitis but also other serious symptoms. To investigate an association between intestinal bacterial flora and resistance to such infections, we screened faecal samples for the presence of enteric bacteria that are able to suppress the growth of O157. Samples from 303 individuals, 35 children (aged [les ]6 years) and 268 adults (aged 20–59 years), were examined. Colonies with different appearances on sorbitol MacConkey agar medium were screened for the production of bacteriocins inhibitory for O157 in an overlay agar plate assay. O157-inhibiting strains were isolated from 52 individuals. The prevalence of these bacteria tended to rise with age, and was significantly higher among 40- to 59-year-old adults (23/101, 22·8%) than among children (3/35, 8·6%; P<0·05). To test the hypothesis that these bacteriocin-producing strains contribute to resistance against O157 in human adults, we examined faecal samples of 25 healthy O157 carriers. Inhibitory bacteria were more prevalent among the latter (9/25, 36·0%) than among age-matched subjects who did not carry O157 (49/268, 18·3%). It appears, therefore, that inhibitory bacteria in the human gut may play a role in inhibiting propagation of O157 and/or suppressing expression of virulence factors by this pathogen.

Type
Research Article
Copyright
© 2006 Cambridge University Press