Fluoroquinolone-Resistant Escherichia coli Infections After Transrectal Biopsy of the Prostate in the Veterans Affairs Healthcare System

BACKGROUND: Recent reports suggest that infections due to fluoroquinolone-resistant Escherichia coli (E. coli) are an increasingly common complication of transrectal biopsy of the prostate (TBP) in the United States. A better understanding of the magnitude and scope of these infections is needed to guide prevention efforts. Our objective is to determine whether the incidence of infections due to fluoroquinolone-resistant E. coli after TBP has increased nationwide in the Veterans Affairs Health Care System and to identify risk factors for infection. METHODS: We performed a retrospective, observational cohort study and a nested case-control study within the US Deparment of Veterans Affairs Healthcare System. The primary outcomes were the incidence of urinary tract infection (UTI) and bacteremia with E. coli and with fluoroquinolone-resistant E. coli strains within 30 days after TBP. Secondary endpoints focused on the correlation between fluoroquinolone-resistance in all urinary E. coli isolates and post-TBP infection and risk factors for infection due to fluoroquinolone-resistant E. coli infection. RESULTS: 245,618 patients undergoing 302,168 TBP procedures from 2000 through 2013 were included in the cohort study, and 59,469 patients undergoing TBP from 2011 through 2013 were included in the nested case-control study. Between 2000 and 2013, there was a 5-fold increase in the incidence of E. coli UTI (0.18%–0.93%) and a 4-fold increase in the incidence of E. coli bacteremia (0.04%–0.18%) after TBP that was attributable to an increase in the incidence of fluoroquinolone-resistant E. coli UTI (0.03%–0.75%) and bacteremia (0.01%–0.14%). The increasing incidence of fluoroquinolone-resistant E. coli infections after TBP occurred in parallel with increasing rates of fluoroquinolone-resistance in all urinary E. coli isolates. By multivariable logistic regression analysis, independent risk factors for fluoroquinolone-resistant E. coli UTI after TBP included diabetes mellitus, fluoroquinolone exposure, prior hospitalization, and prior cultures with fluoroquinolone-resistant gram-negative bacilli. CONCLUSION: In the Veterans Affairs Healthcare System, the incidence of E. coli infection after TBP has increased significantly since 2000 due to a dramatic rise in infections with fluoroquino-lone-resistant E. coli.