Molecular detection of mecA gene from methicillin-resistant Staphylococcus aureus isolated from clinical and environmental samples and its potential inhibition by phytochemicals using in vitro and in silico approach

Abstract

The increasing prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) has posed significant challenges in clinical and environmental settings. MRSA's resistance is attributed to the mecA gene, which encodes the penicillin-binding protein 2a (PBP2a), conferring resistance to β-lactam antibiotics. This study aimed to molecularly detect the mecA gene in MRSA isolates from clinical and environmental samples and identify potential inhibitors of PBP2a using in vitro and in silico approaches. A total of 180 samples were collected, isolating 64 Staphylococcus aureus strains, of which 10 (37%) were confirmed as MRSA. Molecular detection confirmed the presence of the mecA gene in these isolates. Phytochemical analysis of Acacia nilotica and Mangifera indica extracts revealed bioactive compounds with antimicrobial properties. In vitro antimicrobial testing showed the plant extracts demonstrated significant inhibitory effects against MRSA, with minimum inhibitory concentrations (MIC) ranging from 0 to 6.20 mg/mL. Molecular docking and molecular dynamics simulation analyses identified three compounds (CID_628694, CID_546930, and CID_620007) with strong binding affinities and stable interactions with PBP2a, suggesting their potential as novel inhibitors. These findings highlight the therapeutic potential of phytochemicals in combating MRSA and provide a basis for future experimental validations.