RESUMEN
Vancomycin is the first-line therapy for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, but its efficacy in adult patients has been questioned. Less is known about the outcomes of MRSA bacteremia treated with vancomycin in pediatric patients. This study reviews the outcomes and clinical characteristics of MRSA bacteremia in children treated with vancomycin and characterizes the microbiologic and molecular features of the bloodstream isolates. A retrospective cohort study was conducted among pediatric patients with MRSA bacteremia treated with vancomycin for >5 days from 1 August 2005 to 31 May 2007 in a large tertiary care center. MRSA bloodstream isolates were characterized by antimicrobial susceptibility testing, PCR analysis of virulence genes, and Diversilab typing. Clinical records were reviewed for outcomes and comorbidities. A total of 22 pediatric patients with MRSA bacteremia were identified. Eleven cases (50.0%) were considered vancomycin treatment failures. Features significantly associated with vancomycin treatment failure were prematurity (P = 0.02) and isolates positive for Panton-Valentine leukocidin (PVL) (P = 0.008). Features typically associated with community-associated MRSA strains were identified in hospital-associated isolates. A dominant clone was not responsible for the high number of treatment failures. Further studies are needed to determine if vancomycin should be the first-line treatment for MRSA bacteremia in premature infants and for PVL-positive isolates.