Background: Biofilm formation is one of the pathogenicity factors of Staphylococcus aureus that can help the bacteria to stick to the other surface and also increase antibiotic resistance pattern. This study aimed to investigate the phenotypic and genotypic indices for formating biofilm in Staphylococcus aureus isolates isolated from infectous samples.

Materials and Methods: 250 Staphylococcus aureus strains isolated from hospital infections were selected. Antibiotic resistance pattern was determined by using disk diffusion method. The ability of biofilm formation was investigated by molecular and phenotypic method.

Results: In this study, 73.5% of isolates were able to bind strongly, 5.33% had the ability of medium connection and 15.4% had the ability of weak connection in biofilm production. The frequency of icaC and icaB genes were 67.3% and 63.2%, respectively. 92.2% of biofilm producing isolates have mecA gene.

Conclusion: The spread of antibiotic resistance in isolates especially isolates that produce biofilm will create serious problems in the hospital therapeutic wards.