Abstract

mecA GENE ASSOCIATED STAPHYLOCOCCUS AUREUS: ROLE FROM GENE TO ANTIMICROBIAL RESISTANCE

Amatul Malasha, Neha Kumari, Avinash Kumar, Sunil Yadav and Vinod Kumar Gupta*

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Abstract

Staphylococcus aureus is a versatile bacterium that thrives in diverse environments, including human skin, soil, water, hospitals, and even sewage and waste. Some strains of S.aureus become antibioticresistance (specifically β-Lactamase ring), making them very difficult to treat, this may causes minor to major infection. This resistance ability develop through natural selection or by the gene transfer. This resistance strain of bacteria S. aureus is called MRSA (Methicillin Resistance Staphylococcus Aureus). There are various genes help in resistance one of them is mecA gene, The mecA gene is a critical genetic determinant responsible for methicillin resistance in Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA). It encodes for an altered penicillin-binding protein, PBP2a, which has a low affinity for β-lactam antibiotics, rendering these antibiotics ineffective. The mecA gene, located within the SCCmec genetic element, can be transferred between bacteria through horizontal gene transfer. Detection of the mecA gene is a standard method for confirming MRSA strains in clinical diagnostics, making it an important target for antimicrobial resistance surveillance and control strategies. It is regulated by two associated regulatory genes: mecI and mecR1, These genes form a repressor- sensor system that controls whether the resistance mechanism is turned on or off, depending on the presence of β-lactam antibiotics. Structurally, PBP2A consists of two domains: C terminal and N-terminal. Detection of the mecA gene via Polymerase Chain Reaction (PCR) is a widely adopted method for diagnosing methicillin-resistant Staphylococcus aureus (MRSA) infections. PCR enables rapid and specific amplification of the mecA gene from clinical samples, facilitating timely identification of MRSA strains. This molecular approach offers advantages over traditional culture-based methods by reducing diagnostic time and enhancing sensitivity and specificity. Consequently, PCR-based detection of mecA is integral to effective infection control and appropriate antimicrobial therapy selection.

Keywords: Methicillin Resistance Staphylococcus aureus, PCR, β-lactam, Staphylococcal cassette chromosome mec (SCCmec), repressor-sensor system, mecA.