Table of Contents
ISRN Microbiology
Volume 2012, Article ID 975143, 4 pages
http://dx.doi.org/10.5402/2012/975143
Research Article

Genetic Determinants of Methicillin Resistance and Virulence among Staphylococcus aureus Isolates Recovered from Clinical and Surveillance Cultures in a Brazilian Teaching Hospital

1Departamento de Doenças Tropicais e Diagnóstico por Imagem, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (UNESP), 18618-970 Botucatu, SP, Brazil
2Departamento de Microbiologia e Imunologia, Instituto de Biociências de Botucatu, Universidade Estadual Paulista (UNESP), 18618-970 Botucatu, SP, Brazil

Received 15 February 2012; Accepted 15 March 2012

Academic Editors: G. Blaiotta and A. Netrusov

Copyright © 2012 Marcus Vinicius Pimenta Rodrigues et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Aims. To quantify the presence of SCCmec types and virulence genes among Staphylococcus aureus colonizing and infecting patients from a teaching hospital. Methods. We analyzed 225 and 84 S. aureus isolates recovered from surveillance and clinical cultures, respectively. Strains were studied for the presence and type of SCCmec, as well as for several virulence genes. Univariate and multivariable analysis were performed in order to identify predictors of invasiveness (defined as isolation from clinical cultures). Results. The presence of SCCmec types III (OR, 2.19, 95% CI, 1.08–4.45) and IV (OR, 5.28 95% CI, 1.35–20.63) and of genes coding for exfoliative toxin B (etb, OR, 6.38, 95% CI, 1.48–27.46) and Panton-Valentine leukocidin (pvl, OR, 2.38, 95% CI, 1.16–4.86) was independently associated with invasiveness. Conclusions. SCCmec types III and IV and virulence genes are associated with greater invasiveness of S. aureus. Patients colonized with methicillin-resistant S. aureus, as well as with strains harboring etb or pvl, may be prone to develop invasive disease. Infection-preventing strategies should be more intensively applied to this group.