| Abstract [eng] |
Staphylococcus aureus infections are among the leading causes of hospital-associated mortality in Lithuania and worldwide. Due to complex virulence mechanisms, this bacterium can evade the immune system, colonize tissues, and cause life-threatening conditions. Particularly concerning are methicillin-resistant S. aureus (MRSA) strains and those capable of biofilm formation, which complicate treatment. This study investigated the genetic and phenotypic virulence factors of MRSA and their correlation. 22 virulence-associated genes were analyzed by PCR, biofilm formation was assessed using a colorimetric method, and extracellular enzyme and siderophore activities were evaluated by plate assays. A total of 90 clinical MRSA isolates from two Vilnius hospitals were examined. The findings contribute to a better understanding of MRSA pathogenesis mechanisms. Genes related to biofilm formation (spa, icaR, fnbA, clfB, and icaD) were the most prevalent, detected in 83.3–100% of isolates. Certain genes were significantly associated with biofilm formation strength: the seb gene was more frequently found in weak biofilm producers (10.5%) compared to moderate producers (0.0%) (p < 0.05), while the ebps gene was more common in moderate biofilm producers (17.4%) than in weak producers (7.9%) (p = 0.05). Although extracellular enzyme and siderophore activities were widespread among MRSA isolates, no statistically significant association with biofilm formation ability was observed. However, protease activity positively correlated with specific biofilm-related genes (icaC, clfA, ebps), and siderophore activity correlated significantly with fnbA, cna and icaC genes. |
