The serum resistome of a globally disseminated multidrug resistant Uropathogenic Escherichia coli clone
Author(s)
Type
Journal Article
Abstract
Escherichia coli ST131 is a globally disseminated, multidrug resistant clone responsible for a high proportion of urinary tract
and bloodstream infections. The rapid emergence and successful spread of E. coli ST131 is strongly associated with
antibiotic resistance; however, this phenotype alone is unlikely to explain its dominance amongst multidrug resistant
uropathogens circulating worldwide in hospitals and the community. Thus, a greater understanding of the molecular
mechanisms that underpin the fitness of E. coli ST131 is required. In this study, we employed hyper-saturated transposon
mutagenesis in combination with multiplexed transposon directed insertion-site sequencing to define the essential genes
required for in vitro growth and the serum resistome (i.e. genes required for resistance to human serum) of E. coli EC958, a
representative of the predominant E. coli ST131 clonal lineage. We identified 315 essential genes in E. coli EC958, 231 (73%)
of which were also essential in E. coli K-12. The serum resistome comprised 56 genes, the majority of which encode
membrane proteins or factors involved in lipopolysaccharide (LPS) biosynthesis. Targeted mutagenesis confirmed a role in
serum resistance for 46 (82%) of these genes. The murein lipoprotein Lpp, along with two lipid A-core biosynthesis enzymes
WaaP and WaaG, were most strongly associated with serum resistance. While LPS was the main resistance mechanism
defined for E. coli EC958 in serum, the enterobacterial common antigen and colanic acid also impacted on this phenotype.
Our analysis also identified a novel function for two genes, hyxA and hyxR, as minor regulators of O-antigen chain length.
This study offers novel insight into the genetic make-up of E. coli ST131, and provides a framework for future research on E.
coli and other Gram-negative pathogens to define their essential gene repertoire and to dissect the molecular mechanisms
that enable them to survive in the bloodstream and cause disease.
and bloodstream infections. The rapid emergence and successful spread of E. coli ST131 is strongly associated with
antibiotic resistance; however, this phenotype alone is unlikely to explain its dominance amongst multidrug resistant
uropathogens circulating worldwide in hospitals and the community. Thus, a greater understanding of the molecular
mechanisms that underpin the fitness of E. coli ST131 is required. In this study, we employed hyper-saturated transposon
mutagenesis in combination with multiplexed transposon directed insertion-site sequencing to define the essential genes
required for in vitro growth and the serum resistome (i.e. genes required for resistance to human serum) of E. coli EC958, a
representative of the predominant E. coli ST131 clonal lineage. We identified 315 essential genes in E. coli EC958, 231 (73%)
of which were also essential in E. coli K-12. The serum resistome comprised 56 genes, the majority of which encode
membrane proteins or factors involved in lipopolysaccharide (LPS) biosynthesis. Targeted mutagenesis confirmed a role in
serum resistance for 46 (82%) of these genes. The murein lipoprotein Lpp, along with two lipid A-core biosynthesis enzymes
WaaP and WaaG, were most strongly associated with serum resistance. While LPS was the main resistance mechanism
defined for E. coli EC958 in serum, the enterobacterial common antigen and colanic acid also impacted on this phenotype.
Our analysis also identified a novel function for two genes, hyxA and hyxR, as minor regulators of O-antigen chain length.
This study offers novel insight into the genetic make-up of E. coli ST131, and provides a framework for future research on E.
coli and other Gram-negative pathogens to define their essential gene repertoire and to dissect the molecular mechanisms
that enable them to survive in the bloodstream and cause disease.
Date Issued
2013-10-03
Date Acceptance
2013-08-12
Citation
PLoS Genetics, 2013, 9 (10)
ISSN
1553-7390
Publisher
Public Library of Science (PLoS)
Journal / Book Title
PLoS Genetics
Volume
9
Issue
10
Copyright Statement
© 2013 Phan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Identifier
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Subjects
Science & Technology
Life Sciences & Biomedicine
Genetics & Heredity
OUTER-MEMBRANE PROTEIN
URINARY-TRACT-INFECTION
SEQUENCE TYPE ST131
DIFFERENTIAL EXPRESSION ANALYSIS
GRAM-NEGATIVE BACTERIA
O-ANTIGEN
BETA-LACTAMASE
LIPOPOLYSACCHARIDE BIOSYNTHESIS
MUREIN LIPOPROTEIN
ESSENTIAL GENES
Publication Status
Published
Article Number
e1003834
Date Publish Online
2013-10-03