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

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.
In this study, the 27 S. aureus isolates and 73 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.
In this study, from 27 S. aureus isolates and 73 S. epidermidis, 25 and 70 isolates had the ability to form biofilms respectively. The results showed that 93% and 96% 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 4 and 11% 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 30% of the S. aureus isolates.
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.