Virulence properties of asymptomatic bacteriuria Escherichia coli.
In asymptomatic bacteriuria (ABU), bacteria colonize the urinary tract without provoking symptoms. Here, we compared the virulence properties of a collection of ABU Escherichia coli strains to cystitis and pyelonephritis strains. Specific urinary tract infection (UTI)-associated virulence genes, hemagglutination characteristics, siderophore production, hemolysis, biofilm formation, and the ability of strains to adhere to and induce cytokine responses in epithelial cells were analyzed. ABU strains were phylogenetically related to strains that cause symptomatic UTI. However, the virulence properties of the ABU strains were variable and dependent on a combination of genotypic and phenotypic factors. Most ABU strains adhered poorly to epithelial cells; however, we also identified a subgroup of strongly adherent strains that were unable to stimulate an epithelial cell IL-6 cytokine response. Poor immune activation may represent one mechanism whereby ABU E. coli evade immune detection after the establishment of bacteriuria.
Mabbett
Amanda N
AN
School of Molecular and Microbial Sciences, University of Queensland, Brisbane, QLD, Australia.
Ulett
Glen C
GC
Watts
Rebecca E
RE
Tree
Jai J
JJ
Totsika
Makrina
M
Ong
Cheryl-lynn Y
CL
Wood
Jacqueline M
JM
Monaghan
Wayne
W
Looke
David F
DF
Nimmo
Graeme R
GR
Svanborg
Catharina
C
Schembri
Mark A
MA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001422:Bacterial Adhesion; D001437:Bacteriuria / Q000382:microbiology*; D018441:Biofilms / Q000254:growth & development; D003556:Cystitis / Q000382:microbiology; D016207:Cytokines / Q000378:metabolism; D004847:Epithelial Cells / Q000382:microbiology; D004926:Escherichia coli / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D006384:Hemagglutination; D006461:Hemolysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011704:Pyelonephritis / Q000382:microbiology; D017262:Siderophores / Q000096:biosynthesis; D014552:Urinary Tract Infections / Q000382:microbiology*; D037521:Virulence Factors / Q000096:biosynthesis* / Q000235:genetics
D016207:Cytokines; D029968:Escherichia coli Proteins; D017262:Siderophores; D037521:Virulence Factors