Biofilm Formation, c-di-GMP Production, and Antimicrobial Resistance in Staphylococcal Strains Isolated from Prosthetic Joint Infections: A Pilot Study in Total Hip and Knee Arthroplasty Patients

Total joint arthroplasty (TJA) and total joint replacement (TJR) are effective treatments for end-stage osteoarthritis, but prosthetic joint infections (PJIs) remain a significant complication. These infections are often associated with bacteria that form biofilms, which contribute to their persistence and resistance to treatment. The aim of this study was to investigate the biofilm-forming ability, cyclic diguanylic acid (c-di-GMP) production, and the presence of biofilm-associated genes in <i>Staphylococcus aureus</i> and coagulase-negative <i>Staphylococci</i> (CoNS) isolates obtained from synovial fluid samples of patients with PJIs following TJA and TJR. A total of 198 samples were analyzed, with bacterial growth detected in 33 samples (16.7%). Among these, 10 strains of <i>S. aureus</i> and 22 strains of CoNS were identified. Biofilm formation was evaluated using the crystal violet assay, and c-di-GMP levels were measured. A statistically significant linear regression was found between biofilm formation and c-di-GMP production (<i>p</i> = 0.016, R² = 0.18). Genetic analysis revealed the presence of biofilm-associated genes, including <i>icaA</i>, <i>clfA</i>, <i>fnbA</i> in <i>S. aureus</i>, and <i>atlE</i>, <i>fbe</i> in CoNS. Furthermore, there was a statistically significant difference in c-di-GMP production between strains harboring the icaA gene and strains without icaA (<i>p</i> = 0.016), while oxacillin resistance was detected more frequently in strains carrying fbe gene (<i>p</i> = 0.031). The study emphasizes the variability in antibiotic resistance profiles among staphylococcal isolates, underscoring the complexity of managing these infections.