[Distribution and resistance trends of pathogens from urinary tract infections and impact on management].

Objective: To assess the bacterial profile and pattern of antibiotic resistance of urinary tract infections (UTIs) pathogens and to determine its clinical impact on management.

Methods: Midstream urine samples were submitted for culture from 1998 to 2002, and 798 isolates were obtained for antimicrobial susceptibility testing including amikacin (AMK), ampicillin (AMP), cefzolin (CFZ), cefuroxime (CXM), ceftriaxone (CRO), ceftaxime (CTX), ceftazidime (CAZ), nalidixoc acid (NAL), ciprofloxacin (CIP), trimethoprim/sulfamethoxazole (SXT), nitrofurantoin (NIT) for Gram-negative bacteria and oxcillin (OXA), ampicillin (AMP), cefzolin (CFZ), ciprofloxacin (CIP), gentamicin (Gen), vancomycin (VAN), trimethoprim/sulfamethoxazole (SXT), nitrofurantoin (NIT) for Gram-positive cocci. beta-lactamases and ESBLs were tested when needed.

Results: Enterobacteriaceae was the most frequently isolated pathogen. Among all the isolates, Escherichia coli accounted for 66.0%, followed by Enterococcus (6.5%), Klebsiella spp. (6.0%), Staphylococcus (5.4%). High resistance rates to CIP (56.0%), SXT (67.0%) and AMP (78.9%) were observed among the E. coli. CIP-resistant E. coli strains are being isolated with increasing frequency. From 1998 to 2002 the incidence of CIP-resistant increased steadily from 46.6% to 59.4%. A higher resistance rate to NAL was apparent. In contrast, NIT displayed a resistance rate of 8.9%, and AMK 4.9%. The ESBLs positive rate was 12.9% among the E. coli and 33.3% among the Klebsiella spp. respectively. A high resistance rate to CIP was also observed among the Staphylococcus (38.1%), Enterococcus (61.5%) and Streptococcus (85.0%), and the beta-lactamases positive rate was 95.2% among the Staphylococcus, but a lower resistance rate to NIT among Staphylococcus (2.4%) and Enterococcus (11.5%).

Conclusions: Resistance rates among common uropathogens continue to evolve and appear to be increasing to many commonly used agents especially to quinolones. Continued surveillance of resistance rates among uropathogens is needed to ensure appropriate recommendations for the treatment of the infections. Currently, the most appropriate agent for the empirical management of UTIs seems to be nitrofurantoin.