Molecular Study of Mec-Phenol Soluble Modulin Gene in Methicillin Resistant Staphylococcus Aureus

Background: Staphylococcus aureus (S. aureus) is a main pathogen associated with different types of hospital ac-quired infections. There are various factors associated with the virulence of S. aureus. Among these factors are biofilm formation, antibiotics resistance, alpha-toxin, and phenol-soluble modulins (PSMs) which are encoded by genes within the core genome. The aims of the present study were to identify the prevalence psm-mec gene in MRSA isolated from different types of hospital acquired infections and to study the association of this gene with biofilm formation capacity in S. aureus. Methods: The study was a retrospective, cross-sectional study that included 150 isolates of MRSA isolated from different clinical samples. Methicillin resistant S. aureus was identified as resistance to cefoxitin disc by disc diffu-sion method, biofilm detection by microplate method, and polymerase chain reaction (PCR) was used for detec-tion of PSM alpha gene. Results: MRSA was identified by phenotypic detection with resistance to cefoxitin disc in 64.7% of the isolated S. aureus. Biofilm formation was detected in 70 isolates (46.7%) with high titer in 61 isolates, intermediate titer in 6 isolates and low titer in 4 isolates. PSM alpha gene detected in 65 (43.3%) of the isolates, Table 1. There was significant association between the presence of PSM alpha gene and formation of biofilm (p = 0.0001). All detected PSM alpha genes were present in 65 (92.8%) of positive S. aureus isolates for biofilm formation. Conclusions: There was high prevalence of the PSM alpha gene in MRSA with association with high titer biofilm form -ing S. aureus. The absence of PSM alpha gene in MRSA strains may reduce the ability of MRSA to form biofilm.

Automated summary

This study investigated the prevalence of psm-mec gene in MRSA isolates and its association with biofilm formation capacity in S. aureus. Results showed a significant association between the presence of PSM alpha gene and biofilm formation, which could potentially lead to new therapeutic strategies.