Journal article
Enterohemorrhagic Escherichia coli O157:H7 gal Mutants Are Sensitive to Bacteriophage P1 and Defective in Intestinal Colonization
Infection and immunity, Vol.75(4), pp.1661-1666
12/11/2006
DOI: 10.1128/IAI.01342-06
PMCID: PMC1865682
PMID: 17158899
Abstract
Enterohemorrhagic
Escherichia coli
(EHEC), especially
E. coli
O157:H7, is an emerging cause of food-borne illness. Unfortunately,
E. coli
O157 cannot be genetically manipulated using the generalized transducing phage P1, presumably because its extensive O antigen obscures the P1 receptor, the lipopolysaccharide (LPS) core subunit. The GalE, GalT, GalK, and GalU proteins are necessary for modifying galactose before it can be assembled into the repeating subunit of the O antigen. Here, we constructed
E. coli
O157:H7
gal
mutants which presumably have little or no O antigen. These strains were able to adsorb P1. P1 lysates grown on the
gal
mutant strains could be used to move chromosomal markers between EHEC strains, thereby facilitating genetic manipulation of
E. coli
O157:H7. The
gal
mutants could easily be reverted to a wild-type Gal
+
strain using P1 transduction. We found that the O157:H7
galETKM
::
aad-7
deletion strain was 500-fold less able to colonize the infant rabbit intestine than the isogenic Gal
+
parent, although it displayed no growth defect in vitro. Furthermore, in vivo a Gal
+
revertant of this mutant outcompeted the
galETKM
deletion strain to an extent similar to that of the wild type. This suggests that the O157 O antigen is an important intestinal colonization factor. Compared to the wild type, EHEC
gal
mutants were 100-fold more sensitive to a peptide derived from bactericidal permeability-increasing protein, a bactericidal protein found on the surface of intestinal epithelial cells. Thus, one way in which the O157 O antigen may contribute to EHEC intestinal colonization is to promote resistance to host-derived antimicrobial polypeptides.
Details
- Title: Subtitle
- Enterohemorrhagic Escherichia coli O157:H7 gal Mutants Are Sensitive to Bacteriophage P1 and Defective in Intestinal Colonization
- Creators
- Theresa Deland Ho - Tufts UniversityMatthew K. Waldor - Tufts University
- Resource Type
- Journal article
- Publication Details
- Infection and immunity, Vol.75(4), pp.1661-1666
- Publisher
- American Society for Microbiology
- DOI
- 10.1128/IAI.01342-06
- PMID
- 17158899
- PMCID
- PMC1865682
- ISSN
- 0019-9567
- eISSN
- 1098-5522
- Language
- English
- Date published
- 12/11/2006
- Academic Unit
- Microbiology and Immunology
- Record Identifier
- 9984297320702771
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