Prevalence of Biofilm Formation and Detection of PSM B Gene in Clinical Isolates of Staphylococcus aureus

Staphylococcus aureus is a common cause of hospital- and community-acquired infections in the world. This microorganism causes a wide range of diseases, and biofilm formation is as an important mechanism for its virulence. Alpha-toxin and phenol-soluble modulins (PSMs) are among the main factors involved in the biofilm formation by S. aureus. The aim of this study was to detect PSM B gene among biofilm-forming S. aureus clinical isolates from hospitalized patients at the 5th Azar Hospital in Gorgan, Iran.

Clinical specimens were collected and examined for presence of S. aureus using conventional microbiological and biochemical tests. Then, biofilm formation ability of S. aureus isolates was evaluated using the microtiter plate assay. In addition, presence of the PSM B gene was assessed using real-time PCR.

Of 1,800 clinical isolates, 60 (3.3%) were identified as S. aureus. Of these isolates, 47 (78.3%) were positive for biofilm formation. The PSM B gene was present in all biofilm-forming isolates. Results of the phenotypic and genotypic biofilm tests were closely linked and the rate of PSM B expression was 80%.

The prevalence of biofilm-producing S. aureus clinical isolates from patients hospitalized in the 5th Azar hospital of Gorgan (Iran) is relatively high, which could pose a serious challenge. Therefore, regular surveillance of biofilm formation in S. aureus isolates and their antimicrobial resistance profiles is highly recommended.