Molecular detection of mecA and mecC-Mediated MRSA nasal carriage among healthcare workers in a tertiary care hospital.

Abstract

Background: Methicillin-resistant Staphylococcus aureus (MRSA) remains a major cause of healthcare-associated infections worldwide. Healthcare workers (HCWs) colonized with MRSA may act as reservoirs for transmission, contributing to hospital- and community-acquired infections. Early detection of MRSA carriage is essential for effective infection-prevention and control.

Methodology: This cross-sectional study was conducted at a tertiary care hospital. A total of 407 HCWs were screened for MRSA colonization using anterior nasal swab specimens. Staphylococcus aureus was identified using standard microbiological techniques. Methicillin resistance was determined phenotypically by the cefoxitin disc diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Genotypic confirmation was performed using real-time polymerase chain reaction (RT-PCR) to detect the mecA and mecC genes. MRSA carriers received 2% intranasal mupirocin followed by repeat screening.

Results: Among 407 HCWs screened, 96 S. aureus isolates were recovered, of which 80 (83.3%) were phenotypically confirmed as MRSA. The overall MRSA nasal carriage rate was 19.65%, with the highest prevalence among interns (40.62%). Male gender was significantly associated with MRSA carriage (p < 0.05). Among the 80 MRSA isolates, mecA was detected in 55 (68.75%), including 30 (37.5%) co-harbouring mecC. No isolate carried mecC alone, while 25 (31.25%) lacked both genes. All carriers became culture-negative after decolonization.

Conclusion: A substantial proportion of HCWs were colonized with MRSA, highlighting their role in nosocomial transmission. Combined phenotypic and genotypic methods improved MRSA detection. Routine surveillance, strict infection-control measures, and targeted decolonization are essential to reduce MRSA transmission.