Microbiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Microbiology 155 (2009), 2907-2918; DOI  10.1099/mic.0.025171-0
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplementary table
Right arrow All Versions of this Article:
mic.0.025171-0v1
155/9/2907    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Google Scholar
Right arrow Articles by House, B.
Right arrow Articles by Barnett Foster, D.
PubMed
Right arrow PubMed Citation
Right arrow Articles by House, B.
Right arrow Articles by Barnett Foster, D.
Agricola
Right arrow Articles by House, B.
Right arrow Articles by Barnett Foster, D.
Microbiology 155 (2009), 2907-2918; DOI  10.1099/mic.0.025171-0
© 2009 Society for General Microbiology

Acid-stress-induced changes in enterohaemorrhagic Escherichia coli O157 : H7 virulence

B. House1, J. V. Kus1, N. Prayitno1, R. Mair2, L. Que1, F. Chingcuanco1, V. Gannon3, D. G. Cvitkovitch2 and D. Barnett Foster1

1 Department of Chemistry and Biology, Ryerson University, Toronto, ON M5B 2K3, Canada
2 Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
3 Public Health Agency of Canada, Lethbridge, Alberta, Canada

Enterohaemorrhagic Escherichia coli (EHEC) O157 : H7 is naturally exposed to a wide variety of stresses including gastric acid shock, and yet little is known about how this stress influences virulence. This study investigated the impact of acid stress on several critical virulence properties including survival, host adhesion, Shiga toxin production, motility and induction of host-cell apoptosis. Several acid-stress protocols with relevance for gastric passage as well as external environmental exposure were included. Acute acid stress at pH 3 preceded by acid adaptation at pH 5 significantly enhanced the adhesion of surviving organisms to epithelial cells and bacterial induction of host-cell apoptosis. Motility was also significantly increased after acute acid stress. Interestingly, neither secreted nor periplasmic levels of Shiga toxin were affected by acid shock. Pretreatment of bacteria with erythromycin eliminated the acid-induced adhesion enhancement, suggesting that de novo protein synthesis was required for the enhanced adhesion of acid-shocked organisms. DNA microarray was used to analyse the transcriptome of an EHEC O157 : H7 strain exposed to three different acid-stress treatments. Expression profiles of acid-stressed EHEC revealed significant changes in virulence factors associated with adhesion, motility and type III secretion. These results document profound changes in the virulence properties of EHEC O157 : H7 after acid stress, provide a comprehensive genetic analysis to substantiate these changes and suggest strategies that this pathogen may use during gastric passage and colonization in the human gastrointestinal tract.

Correspondence
D. Barnett Foster
dfoster{at}ryerson.ca

Abbreviations: EHEC, enterohaemorrhagic Escherichia coli; EPEC, enteropathogenic E. coli; RT, room temperature; TTSS, type III secretion system

The GEO accession number for the microarray data associated with this paper is GSE14069.

A supplementary table of primers is available with the online version of this paper.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
INT J SYST EVOL MICROBIOL MICROBIOLOGY J GEN VIROL
J MED MICROBIOL ALL SGM JOURNALS
Copyright © 2009 Society for General Microbiology.