Frequency of Adhesion Genes and Biofilm Formation Ability among Staphylococcus aureus Isolated from Clinical Samples of Patients

Background and Objectives: Microbial biofilms is one of the main mechanisms for the survival of bacteria in different environments and settings. Therefore, in the present study, we evaluated drug resistance, the ability of biofilm formation and any relationship to the presence of adhesion genes among Staphylococcus aureus, isolated from clinical samples of patients. Materials and Methods: A total of 130 S. aureus strains isolated from different clinical samples were included in this cross-sectional study performed during December 2017 and July 2018. Antimicrobial susceptibility test was done using the Kirby–Bauer disk diffusion method. Biofilm formation was performed by microtiter plate test method. PCR amplification was used to detect methicillin-resistant S. aureus strains (MRSA) and adhesion genes including fnbA, fnbB, clfA, clfB, eno, psm, and sasX genes. Results: The frequency of the MRSA and methicillin-sensitive S. aureus (MSSA) strains were 52.3% (68/130) and 47.7% (62/130), respectively. Regarding antibiotic susceptibility pattern, all isolates were resistant to penicillin and 76.5% and 51.5% of the MRSA strains were sensitive to co-trimoxazole and clindamycin, respectively. The most antibiotic resistance was against tetracycline (72.1%) and erythromycin (66.2%). Out of 130 S. aureus isolates, 46.9% (61/130) were positive to the ability of biofilm formation. Moreover, the most prevalent biofilm-positive isolates were among blood samples (14.6%). The results of PCR assay showed that the most frequent MSCRAMMs genes among S. aureus isolates were, clfA, clfB, and eno with 85.4%, 82.3%, and 82.3%, respectively. Furthermore, sasX and psm genes were detected among both MRSA and MSSA strains. Conclusion: Results indicate the presence of high rate S. aureus biofilm formation isolated from blood samples. In addition, sasX and psm genes were detected not only in MRSA strains but also among MSSA strains. A remarkable of antibiotic resistance MRSA isolates still remains as a significant risk of infection in hospitalized patients.