Assessment of pathogen frequency and resistance patterns among pediatric patient isolates: report from the 2004 SENTRY Antimicrobial Surveillance Program on 3 continents

Abstract

Selecting empiric or directed therapy for pathogens isolated from pediatric patients can be problematic. Many antimicrobial agents are not indicated for use in pediatric patients, and regional variations of resistance mechanisms have been reported. The purpose of this study was to analyze antimicrobial resistance patterns and pathogen occurrence rates in pediatric-aged patient infections on 3 continents using data from the SENTRY Antimicrobial Surveillance Program. A total of 3537 clinical isolates were collected from 47 medical centers in 2004. With a protocol that dictated a sampling of 80 consecutive isolates from children (< or =18 years of age), all samples were forwarded to a central laboratory for reference susceptibility testing. Broth microdilution methods and current Clinical and Laboratory Standards Institute breakpoint criteria were used. The 15 most frequently observed pathogens accounted for 93.6% of all isolates. Staphylococcus aureus was the most common pathogen isolated in North America (27.4%) and Europe (19.0%), but Escherichia coli was most common in Latin America (19.3%). All Streptococcus pneumoniae strains from North America and Latin America were susceptible to the newer fluoroquinolones, gatifloxacin and levofloxacin. However, 2 S. pneumoniae strains from Italy were resistant to gatifloxacin, levofloxacin, and ciprofloxacin (> or =4 microg/mL). Ribotype and pulsed-field gel electrophoresis patterns found that these resistant pneumococci were clonal. Numerous strains of Klebsiella spp. (22.5%), E. coli (4.5%), and Proteus mirabilis (4.9%) exhibited phenotypic extended-spectrum beta-lactamase resistance patterns. Four Pseudomonas aeruginosa strains (3 from Latin America and 1 from Europe) were multidrug resistant, 2 P. aeruginosa isolates from Turkey were resistant to polymyxin B (> or =4 microg/mL), and 8.7% of Stenotrophomonas maltophilia isolates from Latin America were resistant to the "drug of choice", trimethoprim/sulfamethoxazole. Physicians should be aware of pathogen occurrences that vary by children's age, geographic location, and prior antimicrobial exposure. Therefore, continued surveillance will be necessary to monitor emerging antimicrobial resistance in the pediatric patient population, especially because new agents such as the fluoroquinolones are used to a greater extent in this age group.