The oxidative stress response regulator OxyR was assessed as both a urinary and extra-urinary virulence factor in Escherichia coli strain UCB34 (O17:K+:H18), a representative of the emergent Clonal Group A (CGA). Compared to UCB34, the isogenic oxyR mutant exhibited increased H2O2 sensitivity, indistinguishable invitro growth, and attenuated virulence in rodent models of urinary tract, subcutaneous infection, and systemic sepsis. Complemented mutants showed virulence levels comparable to parent strains in all models. These findings uniquely fulfill molecular Koch's postulates for a putative virulence factor of CGA, provide experimental evidence of an extra-urinary virulence promoting trait in CGA, and document a role for OxyR in local and systemic extra-urinary E.coli infections.
Bibliographical noteFunding Information:
This material is based upon work supported by Office of Research and Development, Medical Research Service, Department of Veterans Affairs (J.R.J., T.A.R.). Dave Prentiss (Minneapolis VA Medical Center) prepared the figures. Charles Dozois (INRS-Institut Armand-Frappier, Laval, Québec, Canada) provided the lac-derivative of the UCB717 parent strain.
- Clonal Group A
- Escherichia coli infections
- Extra-urinary infections
- Urinary tract infections