Antimicrobial resistance patterns of isolates from urine cultures at an oncological center

Objective. To describe the patterns of antimicrobial resistance of organisms isolated from urine cultures at a teaching oncological hospital for adult patients. Material and Methods. All strains obtained from urine cultures from 1998 to 2005 were included. Mean susceptibilities were obtained for each antimicrobial tested; nosocomial and community-acquired isolates were analyzed separately. Results. A total of 9 232 positive urine cultures were obtained (20.7%) from 44 447 samples taken. Gram negative bacteria were reported in 78.8%, Gram-positive in 13.8% and yeasts in 7.4%. Escherichia coli was the most frequently isolated bacterium (41.3%); antimicrobial resistance was higher in nosocomial isolates than in community strains (amikacin 92.4 vs. 97%, ceftazidime 83.1 vs. 95.1% and ciprofloxacin 46.2 vs. 58.6%). Pseudomonas aeruginosa showed a greater resistance to amikacin and ceftazidime in nosocomial cultures compared to community-acquired bacterial cultures (55.7 vs. 66.6% and 65.5 vs. 84.8% respectively). Vancomycin-resistant enterococci were found in only 2.5% (3 of 119 E faecium isolates). Conclusions. Higher bacterial resistance was observed in nosocomial cultures than in community ones. Antimicrobial resistance was found to be progressively increasing for E. coli, the most frequent pathogen isolated both in nosocomial and community infections. We consider imperative the establishment of an intense educational campaign for the use and control of antibiotics.