Two-year assessment of the pathogen frequency and antimicrobial resistance patterns among organisms isolated from skin and soft tissue infections in latin American hospitals: Results from the SENTRY antimicrobial surveillance program, 1997-98

Abstract

Objectives: This study was conducted to evaluate the frequency of occurrence and antimicrobial susceptibility of bacterial isolates collected from patients with skin and soft tissue infections (SSTI) in Latin American hospitals, as part of the SENTRY Antimicrobial Surveillance Program. The dissemination of multidrug- resistant methicillin-resistant Staphylococcus aureus (MDR-MRSA) among the Latin American countries also was studied. Material and Methods: A total of 885 bacterial isolates were analyzed. At the monitoring laboratory, antimicrobial susceptibility testing tilizing the reference broth microdilution method and confirmation of species identification were performed. Enterobacteriaceae possibly producing extended-spectrum β-lactamases (ESBL) and MDR-MRSA isolates were genotyped by ribotyping using the RiboPrinter TM and by pulsed-field gel electrophoresis. Results: Staphylococcus aureus (31 %) was the most common etiologic agent causing SSTI, followed by Escherichia coli (13.4%) and Pseudomonas aeruginosa (11 %). Thirty-one percent of S. aureus isolates were resistant to oxacillin (methicillin). The presence of ESBL phenotypes was markedly higher among the Klebsiella pneumoniae (35.5%) than E. coli isolates (10.2%). Meropenem was the compound with the highest susceptibility rate among the Enterobacteriaceae (100%) and P. aeruginosa (95%) isolates. A great genetic similarity was observed among the MDR-MRSA in Latin America. Conclusion: High resistance rates to antimicrobial drugs among the most frequent bacterial pathogens were observed in 10 medical centers in Latin America. This study also demonstrated a clonal dissemination of a MDR-MRSA strain in several nations.