Detection of Genes That Encoding the Collagen (Cna) and Fibronectin (FnB) binding Protein of Staphylococcus aureus Isolates by Multiplex- PCR

Staphylococcus aureus encode variety of virulence factors genes which may induce various infections individually or synergistically. The aim of this study was to assess virulence factors including collagen binding (Cna)، and Fibronectin binding (FnB) proteins at molecular level، in S. aureus strains isolated from clinical and nasal specimens of patients admitted to University Teaching Hospitals of Tabriz. In a limited period، from July to February 2009، 1936 various clinical specimens and 504 specimens from anterior nares from cardiac patients were collected. The S. aureus isolates were identified by phenotypic methods and later confirmed by PCR with detection of nuc and femB genes. MRSA strains were identified using disk diffusion method and later confirmed by detection of mecA gene. Multiplex PCR was performed to detect the above mentioned genes as well as to spot virulence factors coded by cna and fnb genes. From 1936 various clinical samples and 504 nasal specimens، 121 and 214 non-duplicate S. aureus strains were isolated respectively. cna was identified in 80. 99% clinical and 17. 29% nasal S. aureus strains. cna had higher prevalence in isolates from septic arthritis، osteomyelitis and endocarditis. fnb was identified in 65. 29% clinical and 54. 67% nasal S. aureus strains and had higher prevalence in isolates from endocarditis، osteomyelitis and burn associated wounds. In both clinical and nasal S. aureus strains، prevalence of virulence factors in MRSA was higher than MSSA. The results of this research indicated that simultaneous detection of nuc، femB and mecA genes not only helps for identification of ُS. aureus isolates، but also is specific and useful for rapid detection of MRSA isolates. Higher prevalence of virulence factors in clinical isolates as compared to strains responsible for colonization and in MRSA over MSSA، shows the role of these factors in invasion and pathogenesis.