Beyond Antimicrobial Resistance: mec-genes Detection as a Factor of Epidemiological Characterization Among Methicillin Resistant Staphylococcus aureus (MRSA) Isolates in a Tertiary Care Hospital, South India

Abstract

Introduction: The global public health concern of Staphylococcus aureus (S. aureus) infection and its spread, particularly methicillin-resistant Staphylococcus aureus (MRSA), is exacerbated by the emergence of mec-genes, which are considered markers of MRSA. The study aims to isolate MRSA in clinical isolates and detect mec-genes using molecular assays, thereby enhancing infection control programs. Materials and Methods: The study involved 381 clinical samples processed by standard laboratory procedures and PCR was performed targeting 16S rRNA gene as a reference and then with nuc-gene to detect Staphylococcus aureus. Further, MRSA was confirmed by PCR (Polymerase Chain Reaction) amplification of S. aureus isolates by sub-typing mecA and mecC gene. Sensitivity and specificity of phenotypic methods was calculated using mecA gene PCR as the gold standard. Results: In the present study, 65.85% clinical isolates were found to have similar homology with Staphylococcus aureus. Uniplex PCR results showed that all 162 isolates with S. aureus-like phenotypes were detected as MRSA carrying mecA gene, but none of them was found to carry mecC gene for MRSA. P-value for both the methods was <0.001, which is considered to be highly significant in statistical analysis. Conclusion: The study found that PCR detection of nuc and mec genes is effectively identifies MRSA from clinical isolates, aiding in infection prevention and recommending its use for confirmatory testing. The study recommends using PCR as a confirmatory test method for MRSA detection to prevent the spread of resistant strains in hospitals and communities.

Keywords

• mrsa
• pcr
• 16s rrna
• nuc-gene
• meca