Prevalence of ica operon related genes in Staphylococcus aureus and Staphylococcus epidermidis clinical isolates

Background and Aim: Infections caused by Staphylococcus species associated with biofilm are considered as a serious clinical concern in medical devices used patients with serious clinical illness and are usually possible source of nosocomial infections. The polysaccharide adhesion mechanism encoded by the ica operon generate a direct role in biofilm formation and infection of the bacteria. In this study, the presence of ica operon were studied in clinical isolates of S. aureus and S. epidermidis in relation to the biofilm formation. Materials and Methods:  In this study, the ۲۷ S. aureus isolates and ۷۳ S. epidermidis isolates were identified by conventional biochemical methods. The ability to biofilm formation was evaluated by colony morphology on Congo red agar (CRA) and test tube. Presence of the ica genes was detected by PCR method. Results: In this study, from ۲۷ S. aureus isolates and ۷۳ S. epidermidis, ۲۵ and ۷۰ isolates had the ability to form biofilms respectively. The results showed that ۹۳% and ۹۶% of the S. aureus isolates and S. epidermidis isolates had the potential to form biofilm respectively. Genetic analysis showed that icaRADBC operon was present in ۴ and ۱۱% of S. aureus isolates and S. epidermidis isolates respectively. The S. epidermidis isolates were more frequently positive for icaA, icaB and icaC than S. aureus while the most prevalent gene was icaD found in ۳۰% of the S. aureus isolates. Conclusion: The results obtained showed that in consistent with other researches; biofilm formation in Staphylococcal isolates was not associated with present of ica operon and presumably depend on several factors.