Prevalence of antimicrobial resistance among respiratory tract isolates in Latin America: results from SENTRY antimicrobial surveillance program (1997-98)

RESUMO

One thousand seventy-three bacterial isolates were collected from patients with community acquired respiratory tract infections (CARTI) in 11 Latin American centers (7 countries) during 1997 and 1998. They were tested against numerous antimicrobial agents by the reference broth microdilution method as part of the ongoing multinational SENTRY Antimicrobial Surveillance Program. Among Streptococcus pneumonia (553 isolates), approximately 61 por cento were susceptible to penicillin. There was a great variation of the penicillin susceptibility rates among participating countries. The highest susceptibility rates were found in Argentina (76.7 porcento) and Brazil (71.9 por cento), while the lowest rate of penicillin susceptibility was detected in Mexico (33.3 por cento). High level resistance to penicillin and resistance to cefotaxime were observed in nearly 10 por cento of the isolates. The newer quinolones, levofloxacin (MIC 2 mg/mL) and gatifloxacin (MIC 0.5 mg/mL), were active against 100 por cento of the isolates tested. Among the other non-B-lactam drugs tested, the rank order of susceptibility against the pneumococci was chloramphenicol (93.9 por cento) > clindamycin (93.2 por cento)> azithromycin (89.1 por cento) > clarithromycin (88.7 porcento) > tetracycline (78.5 por cento) > trimethoprim/sulfamethoxazole (55.7 por cento). The percentage of Haemophilus influenzae (361 isolates) isolates resistant to amoxicillin was 12.7 por cento (B-lactamase positive). Among Moraxella catarrhalis (159 isolates) isolates, only 8.2 por cento were susceptible. Clavulanic acid restored the activity of amoxicillin against both species. Trimethoprim/sulfamethoxazole was active against only 59.5 por cento of H. influenzae, while susceptibility to this compound among M. catarrhalis was 96.1 porcento. All other compounds tested were active against > 95 por cento of H. influenzae and M. catarrhalis isolates. These species were susceptible to levofloxacin (MIC90 (less or equal) 0.5 µg/mL for both) and gatifloxacin (MIC90 (less or equal) 0.03 µg/mL for both) with very low MICs. Our results indicate that penicillin resistance rates are particularly high among pneumococci in some countries. The never fluoroquinolones show and excellent potency and spectrum against pathogens causing community acquired respiratory infections in Latin America.