Evaluation of icaA and icaD Genes Involved in Biofilm Formation in Staphylococcus aureus Isolates from Clinical Sources Using Reverse Transcriptase PCR.

Staphylococcus aureus is recognized for its capacity to generate biofilms, which facilitate bacterial adhesion to diverse substrates and present a significant challenge to therapeutic intervention. The process of biofilm formation is dependent on the icaABCD operon, with the icaA and icaD genes playing a pivotal role in this intricate process. The objective of this study is to investigate the role of these genes in the biofilm formation of S. aureus isolates sourced from clinical settings. A total of 100 S. aureus isolates were collected from clinical sources and subsequently subjected to DNA and RNA extraction using a commercial kit from Kiagen Co. To transcribe the RNA samples into cDNA, a commercial kit from Kiagen Co. was employed. The capacity to produce phenotypic and molecular biofilm formation was then measured using the microtiter plate method and PCR, respectively. The expression levels of the icaA and icaD genes were determined via RT-PCR (Reverse transcription polymerase chain reaction). The results indicated that 95% (95%) of the isolates were capable of producing biofilm, with 16 (16%) producing weak, 64 (64%) producing medium, and 15 (15%) producing strong biofilms. Furthermore, the icaA gene was detected in 72% of the isolates, while the icaD gene was detected in 58%. Of these isolates, 70 (97.2%) expressed the icaA gene, and 53 (73.6%) expressed the icaD gene. Conversely, four isolates (5.5%) that possessed the icaA gene but lacked the icaD gene did not form biofilm. One strain did not express either of the genes. The presence of either the icaA or icaD gene is crucial for the development of biofilm. However, further investigation is necessary to fully comprehend the intricacies of biofilm formation.