TITLE:
Virulence Factors in Methicillin-Resistant Staphylococcus aureus Isolated from ICU Units in Brazil
AUTHORS:
Simone G. Souza, Guilherme B. Campos, Pollianna S. Oliveira, Daniel S. Sousa, Danilo C. C. Da Silva, Verena M. Santos, Aline T. Amorim, Angelita M. O. G. Santos, Jorge Timenetsky, Mariluze P. Cruz, Regiane Yatsuda, Lucas M. Marques
KEYWORDS:
MRSA; MSSA; Virulence Factor; Hospitalar Infection
JOURNAL NAME:
Advances in Microbiology,
Vol.4 No.4,
March
21,
2014
ABSTRACT: Species of Staphylococcus are common in hospital infection (HI). Methicillin resistant S. aureus (MRSA) has also become a
serious problem in Brazilian HI. The aim of this study was to characterize the
pathogenicity of methicillin-resistant S.
aureus (MRSA) and methicillin-sensitive Staphylococcus
aureus (MSSA) isolated in public hospitals. The clinical isolates were
obtained from intensive care unit. The MRSA and MSSA strains were genotyped by
PCR for detection genes related to virulence factors. Moreover, the strains
were tested for biofilm formation and cytokine induction in macrophages. Three
strains of MRSA (9.68%) expressed the Sea gene, one (3.23%) Seb, 17 (54.84%)
Spa and seven (22.58%) had PVL. Two MSSA strains (2.98%) expressed the Sea
gene, three (4.48%) Seb, 18 (26.87%) Spa and 11 (16.42%) showed positive
results for the PVL gene. There was no expression of Sec and CflA between MRSA
and MSSA strains. Among MRSA and MSSA isolates, none statistical differences were observed in biofilm
production. The analysis of cytokine induction in the inflammatory response of
J774 macrophages by MRSA and MSSA isolates did not show statistical difference.
Understanding the mechanisms of pathogenesis of S. aureus could provide important clues for both preventing and
treating infection caused by these organisms.