Correlation between levofloxacin consumption and the incidence of nosocomial infections due to fluoroquinolone-resistant Escherichia coli

Background/purpose The relationship between fluoroquinolone resistance in Escherichia coli isolates causing nosocomial infection and hospital antibiotic consumption were investigated. Restriction of levofloxacin use was implemented to control the incidence of fluoroquinolone-resistant E coli in the hospital. Methods The study was conducted from January 2004 to December 2010. Antimicrobial agent consumption was obtained from the pharmacy computer system and presented as the defined daily doses per 1000 patient-days every 6 months. The incidence of fluoroquinolone-resistant E coli isolates causing nosocomial infections was obtained from the Department of Infection Control every 6 months. An antimicrobial stewardship program, restricting levofloxacain use, was implemented in July 2007. Results The incidence of fluoroquinolone-resistant E coli causing nosocomial infections was significantly correlated with fluoroquinolone usage (p = 0.005), but not with the use of third- or fourth-generation cephalosporins, piperacillin-tazobactam, or carbapenems. Parenteral (p = 0.002), oral (p = 0.018), and total levofloxacin (p = 0.001) use were significantly correlated with the extent of fluoroquinolone resistance. With a reduction of levofloxacin use, a decrease of the incidence of fluoroquinolone resistance in E coli isolates was observed. Conclusion There is a significant correlation between levofloxacin use and the incidence of nosocomial fluoroquinolone-resistant E coli isolates. The incidence of fluoroquinolone-resistant E coli could be reduced by limiting levofloxacin consumption.