Activity and spectrum of 22 antimicrobial agents tested against urinary tract infection pathogens in hospitalized patients in Latin America: report from the second year of the SENTRY Antimicrobial Surveillance Program (1998)

The potency and spectrum of various antimicrobial agents tested against 434 bacterial isolates causing urinary tract infection (UTI) in hospitalized p atients in Latin America were evaluated. The genotypes of the extended-spec trum beta-lactamase-producing and selected multi-resistant isolates were al so evaluated by molecular typing techniques. Escherichia coil (60.4%) was t he most common aetiological agent causing UTI, followed by Klebsiella spp. (11.2%) and Pseudomonas aeruginosa (8.3%). In contrast, Enterococcus spp. i solates caused only 2.3% of UTIs. Fewer than 50% of E. coli isolates were s usceptible to broad-spectrum penicillins. The resistance rates to ciproflox acin and the new quinolones were also high among these isolates. The molecu lar characterization of ciprofloxacin-resistant E coli showed that most of them have a double mutation in the gyrA gene associated with a single mutat ion in the parC gene. The Klebsiella pneumoniae isolates studied demonstrat ed high resistance rates to beta-lactam drugs, including broad-spectrum cep halosporins. The carbapenems were the compounds with the highest susceptibi lity rate among these isolates (100.0% susceptible) followed by cefepime (9 1.7% susceptible). Meropenem, imipenem and cefepime were also the most acti ve drugs against Enterobacter spp. Among P. aeruginosa isolates, meropenem (MIC50, 2 mg/L) was the most active compound, followed by imipenem (MIC50, 4 mg/L), cefepime (MIC50, 8 mg/L) end ceftazidime (MIC50, 16 mg/L). The res ults presented in this report confirm that bacterial resistance continues t o be a great problem in Latin American medical institutions.