A retrospective study based on the electronic database of a university hospital was carried out to investigate the prevalence of etiological agents and their susceptibilities to antibiotics, among adult outpatients (> 18 years old) with urinary tract infections. Nine hundred and fifty-seven positive urine cultures were identified between January 2000 and December 2004. Escherichia coli, Proteus mirabilis and Klebsiella sp were the three principal bacterial etiological agents. Trimethoprim-sulfamethoxazole presented the highest prevalence of bacterial resistance (46.9%), followed by cefalotin (46.7%), nalidixic acid (27.6%) and nitrofurantoin (22.3%). Over the study period, nalidixic acid presented annual increases of 5.9% in the rate of bacterial resistance (p = 0.02). Ciprofloxacin also showed an increasing trend, of 3.3% per year (p = 0.07). This study demonstrated that the antibiotics that are widely recommended for empirical treatment of urinary tract infection in adults presented high rates of bacterial resistance among the population studied.
Urinary tract infection; Bacterial resistance; Antibiotics; Urine culture; Retrospective study
