Detection of intercellular adhesion (ica) genes involved in biofilm and slime formation in clinical isolates of Staphylococcus aureus harboring mecA gene

Prevalence of methicillin resistant Staphylococcus aureus (MRSA) strains is one of the most important health care problems and life-threatening in worldwide. The methicillin resistant S. aureus strains producing biofilm and slime have potential to colonize and transmit. The present study was conducted to detect intercellular adhesion (ica) genes involved in biofilm and slime formation in clinical isolates of methicillin resistant S. aureus harboring mecA gene.
In this cross-sectional study, a total of 85 bacterial isolates suspected to S. aureus were prepared from clinical samples. The antibiotic susceptibility testing of bacteria to the penicillin, gentamicin, oxacillin, ciprofloxacin, ofloxacin and vancomycin was carried out based on disk diffusion agar method. Biofilm and slime formation of bacteria were examined by tissue culture polystyrene plate (TCP) and Congo red agar (CRA). The presence and frequency of ­icaA, icaD and mecA genes were detected by multiplex PCR.
45 out of 85 (52.94%) S. aureus isolates were resistant to the methicillin. All of methicillin resistant S. aureus were able to produce biofilm and slime. Consumedly surface hydrophobicity was seen in 55.55% and 100% of strains producing strong biofilm and slime, respectively. The ­icaA, icaD and mecA genes were present in all biofilm and slime producing isolates.
Our results showed that the all methicillin resistant S. aureus isolates with some abilities, including polysaccharide intercellular adhesion, bacterial attachment, biofilm and slime production were positive for icaA and icaD genes.