Assessment of Knack of Clinical Staphylococcus Aureus Isolates for the Biofilm Formation and Presence of icaABCD Family Genes DC31-DC36
Dr. Hossein Samadi Kafil,
Golgasht Ave faculty of Medicine, Department of Medical Microbiology, Tabriz, Az-Sharghi, Iran.
Introduction: Superbug known as Staphylococcus aureus possess a tendency to form biofilm, which has a significant role in causing infection and abating host defense response. Amongst many mechanisms, biofilm formation depends on the icaABCD operon involved in the synthesis of a polysaccharide intercellular adhesion.
Aim: To investigate biofilm forming ability of S. aureus isolates by phenotypic and genotypic methods.
Materials and Methods: Of the 97 S. aureus clinical isolates collected, the quantitative biofilm formation was determined by microtiter plates. All S. aureus isolates were examined for detection of the icaABCD genes and mecA gene by using PCR method. Statistical analysis was performed with SPSS program version 17.0.
Results: Among 97 S. aureus isolates from blood, wound, skin, surgery, internal, burn and infectious wards, urine and body fluids specimens, five isolates appeared as strong biofilm producer, while 28 displayed moderate biofilm formation, and 55 showed weak biofilm formation. Nine isolates did not reveal biofilm production on microtiter plates. The frequency of icaA, icaB, icaC and icaD genes in S. aureus isolates was 81 (83.5%), 71 (73.2%), 51 (52.5%) and 97 (100%), respectively. There was no relation between presence of icaABCD genes and biofilm formation (p=0.74).
Conclusion: The presence of biofilm genes may not coincide with the ability to produce biofilm or vice versa. At the results, S. aureus clinical isolates possess different capacity to produce biofilm and adhesion. Methicillin resistance and susceptible isolates may not differ in their capacity to form biofilm.