Biofilm-Forming Methicillin-Resistant Staphylococcus aureus: A Comprehensive Phenotypic and Genotypic Review

Methicillin-resistant Staphylococcus aureus (MRSA) is a major global pathogen, capable of forming biofilms that confer enhanced antimicrobial tolerance, virulence, and persistence in both hospital and community settings. Biofilms are structured microbial communities encased in extracellular polymeric substances, composed of polysaccharides, proteins, and extracellular DNA. Complex genetic networks, including the ica operon, the agr quorum-sensing system, the sarA regulatory system, and stress-response genes such as sigB, regulate MRSA biofilm formation. Phenotypic methods (Congo red agar, microtiter plate, and tube test) and genotypic assays (PCR-based detection of ica, fnbA/B, clfA/B, sarA, and agr) provide insights into biofilm capacity and virulence potential. Clinically, MRSA biofilms contribute to device-related infections, chronic wounds, and recurrent infections, challenging conventional therapies such as vancomycin, daptomycin, and rifampicin. Emerging strategies, including enzymatic matrix degradation, bacteriophage therapy, quorum-sensing inhibitors, and nanoparticle-based drug delivery, offer potential alternatives. This review synthesizes current knowledge on MRSA biofilm phenotypes and genotypes, highlighting molecular mechanisms, clinical significance, and therapeutic approaches.