Chun-Yu Lin¹, Shu-Hua Huang², Tun-Chieh Chen^1,3, Po-Liang Lu^1,3, Wei-Ru Lin¹, Yen-Hsu Chen^1,3
1Division of Infectious Disease, Department of Internal Medicine and ²Infection Control Committee,Kaohsiung Medical University Chun-Ho Memorial Hospital, Kaohsiung Medical University, Kaohsiung; and ³Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

Received: December 16, 2006     Revised: May 3, 2007     Accepted: June 1, 2007

Corresponding author: Dr. Po-Liang Lu, 100 Tzyou 1st Road, Kaohsiung 807, Taiwan. E-mail: This e-mail address is being protected from spam bots, you need JavaScript enabled to view it

Background and Purpose: Increasing rates of fluoroquinolone resistance among Escherichia coli have been reported in Taiwan and worldwide. We aimed to identify the risk factors of ciprofloxacin resistance in urinary E. coli isolates.

Methods: Patients with positive urine culture result for E. coli and resistance to ciprofloxacin between September 1, 1999 and December 31, 1999 were prospectively identified as cases, and compared with ciprofloxacin-susceptible E. coli isolates (controls). The case:control ratio was 1:2. Data were collected with standardized case record forms.

Results: Sixty one cases and 122 controls were compared. Multivariate analysis indicated that urinary tract catheterization (odds ratio [OR] = 2.631, 95% confidence interval [CI] = 1.058-6.544; p=0.037) and prior exposure to quinolones (OR = 13.072, 95% CI = 3.367-50.75; p<0.001) were independent risk factors for ciprofloxacin resistance in urinary E. coli isolates. Compared with ciprofloxacin-susceptible E. coli isolates, ciprofloxacin-resistant E. coli isolates from urine specimens had a significantly higher rate of resistance to all other tested antimicrobial agents, except amikacin and imipenem.

Conclusions: In patients with urinary tract infection, urinary catheterization and prior quinolone exposure areassociated with a high risk of ciprofloxacin-resistant E. coli which may cause treatment failure.

Key words: Ciprofloxacin; Drug resistance, bacterial; Escherichia coli; Risk factors; Urinary tract

J Microbiol Immunol Infect. 2008;41:325-331.