Escherichia coli (E. coli) is the micro-organism most frequently identified in urinary tract infections in adults. The authors analysed the nalidixic acid resistance rate of E. coli isolated over 12 consecutive months in a urology department.
Material and method: All E. coli-positive bacteriological examinations from a urology department during 2004 were retrospectively reviewed. Seventy five bacteriological examinations from 68 patients were positive for E. coli, corresponding to 67 urine cultures, 6 blood cultures and 2 drained collections. Twenty patients had taken fluoroquinolones during the previous 6 months and 10 patients were diabetic. A nalidixic acid-resistant (NR) E. coli was isolated in 11 patients (16%) aged 22 to 81 years (median: 58 years). Patients with nalidixic acid-resistant (NR) E. coli were compared to patients with nalidixic acid-susceptible (NS) E. coli.
Results: Predictive factors for nalidixic acid resistance of E. coli were fever higher than 38.4 degrees C (p = 0.022), leukocytosis (p = 0.002) and use of fluoroquinolones during the previous 6 months (p = 0.046).
Conclusions: Prescription of a non-fluoroquinolone antibiotic may be preferable in the case of recent use of fluoroquinolones and signs of severe infection (leukocytosis and fever higher than 38.4 degrees C).