SCCmec types and pvl gene in methicillin-resistant Staphylococcus aureus strains from children hospitalized in a tertiary care hospital in Mexico

Background : The aim of this study was to determine the prevalence, SCCmec types, presence of the Panton-Valentine leukocidin (PVL) gene, and susceptibility to antibiotics of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from hospitalized children. Methods : From August 2009 to September 2011, 291 S. aureus strains were isolated from normally sterile body sites, of which 190 (65%) were MRSA. One hundred and two of the MRSA strains were genetically evaluated. SCCmec genotypes were identified by M-PCR and the PVL gene (pvl) by end-point PCR. Resistance to erythromycin, rifampicin, clindamycin, and trimethoprim-sulfamethoxazole (SXT) was assessed by Kirby-Bauer disk diffusion method in accordance with the Clinical and Laboratory Standards Institute guidelines of 2012. Results : Of the 102 strains evaluated, 97 (95%) were SCC mec type II, 5 (5%) were SCC mec type IVa, and all (100%) were pvl-negative. Resistance to erythromycin, clindamycin, rifampicin, and SXT was 97%, 95%, 0%, and 0%, respectively. Conclusions : The prevalence of hospital-acquired MRSA was high. SCC mec type II was predominant and the pvl gene appeared not to play any role in the virulence of the MRSA strains from hospitalized children.