Ciprofloxacin resistance was identified in 18% and 6% of consecutively collected, clinically significant urinary tract isolates of Escherichia coli from inpatients and outpatients, respectively. In comparison to ciprofloxacin-susceptible isolates, there were fewer resistant isolates that expressed beta-hemolysis (outpatient, 9% versus 87%, P < 0.0001; inpatient, 4% versus 76%, P < 0.0001) and that had a papEF genotype, genes encoding P fimbriae (outpatient, 30% versus 70%, P ؍ 0.0004; inpatient, 26% versus 70%, P < 0.0001).Escherichia coli is the principle cause of urinary tract infections in both community and hospital settings in North America. Two of the major uropathogenic virulence factors expressed by E. coli include a hemolysin protein and the mannose-resistant P fimbriae. Hemolysin assists in the acquisition of iron to regulate the expression of virulence factors (22). P fimbriae are encoded by a "pilus associated with pyelonephritis" pap operon which can be carried on one or more mobile genetic elements called pathogenicity-associated islands (PAIs) (22).