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Comparison of Asymptomatic Bacteriuria Escherichia coli Isolates from Healthy Individuals versus Those from Hospital Patients Shows that Long-Term Bladder Colonization Selects for Attenuated Virulence Phenotypes

Salvador, Ellaine; Wagenlehner, Florian; Koehler, Christian-Daniel; Mellmann, Alexander; Hacker, Joerg; Svanborg, Catharina LU and Dobrindt, Ulrich (2012) In Infection and Immunity 80(2). p.668-678
Abstract
Asymptomatic bacteriuria (ABU) is a condition where bacteria stably colonize the urinary tract, in a manner closely resembling commensalism at other mucosa! sites. The patients carry >10(5) CFU/ml for extended periods of time and rarely develop symptoms. Contrasting the properties of ABU strains to those of uropathogenic isolates causing symptomatic infection is therefore highly relevant to understand mechanisms of bacterial adaptation. The prototype ABU strain Escherichia coli 83972 has a smaller genome than uropathogenic E. coli (UPEC) strains with deletions or point mutations in several virulence genes, suggesting that ABU strains undergo a programmed reductive evolution within human hosts. This study addressed if these observations... (More)
Asymptomatic bacteriuria (ABU) is a condition where bacteria stably colonize the urinary tract, in a manner closely resembling commensalism at other mucosa! sites. The patients carry >10(5) CFU/ml for extended periods of time and rarely develop symptoms. Contrasting the properties of ABU strains to those of uropathogenic isolates causing symptomatic infection is therefore highly relevant to understand mechanisms of bacterial adaptation. The prototype ABU strain Escherichia coli 83972 has a smaller genome than uropathogenic E. coli (UPEC) strains with deletions or point mutations in several virulence genes, suggesting that ABU strains undergo a programmed reductive evolution within human hosts. This study addressed if these observations can be generalized. Strains causing ABU in outpatients or hospitalized patients after catheterization or other invasive procedures were compared to commensal E. coli isolates from the intestinal flora of healthy individuals. Notably, clonal complex 73 (CC73) was a prominent phylogenetic lineage dominated by ABU isolates. ABU isolates from outpatients and hospitalized patients had a similar overall virulence gene repertoire, which distinguished them from many commensals, but typical UPEC virulence genes were less frequently attenuated in hospital strains than in outpatient strains or commensals. The decreased virulence potential of outpatient ABU isolates relative to that of ABU strains from hospitalized patients supports the hypothesis that loss of expression or decay of virulence genes facilitates long-term carriage and adaptation to host environments. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Infection and Immunity
volume
80
issue
2
pages
668 - 678
publisher
American Society for Microbiology
external identifiers
  • wos:000299661200020
  • scopus:84857165872
ISSN
1098-5522
DOI
10.1128/IAI.06191-11
language
English
LU publication?
yes
id
11f4a370-9afa-4ed1-bab3-447e1b6a3e05 (old id 2416160)
date added to LUP
2012-04-02 09:37:04
date last changed
2017-07-02 03:05:21
@article{11f4a370-9afa-4ed1-bab3-447e1b6a3e05,
  abstract     = {Asymptomatic bacteriuria (ABU) is a condition where bacteria stably colonize the urinary tract, in a manner closely resembling commensalism at other mucosa! sites. The patients carry >10(5) CFU/ml for extended periods of time and rarely develop symptoms. Contrasting the properties of ABU strains to those of uropathogenic isolates causing symptomatic infection is therefore highly relevant to understand mechanisms of bacterial adaptation. The prototype ABU strain Escherichia coli 83972 has a smaller genome than uropathogenic E. coli (UPEC) strains with deletions or point mutations in several virulence genes, suggesting that ABU strains undergo a programmed reductive evolution within human hosts. This study addressed if these observations can be generalized. Strains causing ABU in outpatients or hospitalized patients after catheterization or other invasive procedures were compared to commensal E. coli isolates from the intestinal flora of healthy individuals. Notably, clonal complex 73 (CC73) was a prominent phylogenetic lineage dominated by ABU isolates. ABU isolates from outpatients and hospitalized patients had a similar overall virulence gene repertoire, which distinguished them from many commensals, but typical UPEC virulence genes were less frequently attenuated in hospital strains than in outpatient strains or commensals. The decreased virulence potential of outpatient ABU isolates relative to that of ABU strains from hospitalized patients supports the hypothesis that loss of expression or decay of virulence genes facilitates long-term carriage and adaptation to host environments.},
  author       = {Salvador, Ellaine and Wagenlehner, Florian and Koehler, Christian-Daniel and Mellmann, Alexander and Hacker, Joerg and Svanborg, Catharina and Dobrindt, Ulrich},
  issn         = {1098-5522},
  language     = {eng},
  number       = {2},
  pages        = {668--678},
  publisher    = {American Society for Microbiology},
  series       = {Infection and Immunity},
  title        = {Comparison of Asymptomatic Bacteriuria Escherichia coli Isolates from Healthy Individuals versus Those from Hospital Patients Shows that Long-Term Bladder Colonization Selects for Attenuated Virulence Phenotypes},
  url          = {http://dx.doi.org/10.1128/IAI.06191-11},
  volume       = {80},
  year         = {2012},
}