Decreased expression of type 1 fimbriae by a pst mutant of uropathogenic Escherichia coli reduces urinary tract infection.
The pstSCAB-phoU operon encodes the phosphate-specific transport system (Pst). Loss of Pst constitutively activates the Pho regulon and decreases bacterial virulence. However, specific mechanisms underlying decreased bacterial virulence through inactivation of Pst are poorly understood. In uropathogenic Escherichia coli (UPEC) strain CFT073, inactivation of pst decreased urinary tract colonization in CBA/J mice. The pst mutant was deficient in production of type 1 fimbriae and showed decreased expression of the fimA structural gene which correlated with differential expression of the fimB, fimE, ipuA, and ipbA genes, encoding recombinases, mediating inversion of the fim promoter. The role of fim downregulation in attenuation of the pst mutant was confirmed using a fim phase-locked-on derivative, which demonstrated a significant gain in virulence. In addition, the pst mutant was less able to invade human bladder epithelial cells. Since type 1 fimbriae contribute to UPEC virulence by promoting colonization and invasion of bladder cells, the reduced bladder colonization by the pst mutant is predominantly attributed to downregulation of these fimbriae. Elucidation of mechanisms mediating the control of type 1 fimbriae through activation of the Pho regulon in UPEC may open new avenues for therapeutics or prophylactics against urinary tract infections.
INRS-Institut Armand-Frappier, Laval, Québec, Canada.
Sébastien
S
Crépin
Sébastien
S
Houle
Marie-Ève
MÈ
Charbonneau
Michaël
M
Mourez
Josée
J
Harel
Charles M
CM
Dozois
D000818:Animals; D001422:Bacterial Adhesion; D002460:Cell Line; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D006159:Guanosine Tetraphosphate / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008808:Mice, Inbred CBA; D009154:Mutation; D001743:Urinary Bladder / Q000166:cytology; D014552:Urinary Tract Infections / Q000382:microbiology*; D056689:Uropathogenic Escherichia coli / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure
D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins; D006159:Guanosine Tetraphosphate