Prevalence of PVL and TSST-1 genes in nasal Staphylococcus aureus carriage among healthcare workers in a tertiary hospital.

INTRODUCTION

Staphylococcus aureus is an important pathogen associated with nosocomial and community-acquired infections. The main reservoirs of S. aureus/MRSA in hospitals are the colonized asymptomatic healthcare workers (HCWs) and patients. The aim of this study was to investigate the prevalence of MSSA and MRSA nasal carriage and their association with pvl and tsst1 genes among HCWs.

METHODOLOGY: A cross-sectional study was performed. A total of 230 HCWs and 200 controls were screened for nasal carriage of S. aureus. All isolates were identified by conventional microbiological methods and confirmed by Vitek. Antimicrobial susceptibility was tested using disk-diffusion and MIC method. PCR was used to detect the mecA, pvl and tsst1 genes.

RESULTS

S. aureus nasal colonization was significantly higher (p < 0.0001) among HCWs, 23% (53/230) compared to the control 0.5% (1/200). Prevalence of MRSA was 9.6% (22/230) among HCWs. All isolates were susceptible to vancomycin and linezolid. Highest resistance was observed with ciprofloxacin and erythromycin among both - MSSAand MRSA. One MSSA isolated showed high-level mupirocin resistance (MIC > 1024 µg/mL). PVL and TSST-1genes were detected 7.4% and 0.8% of HCWs, respectively, with higher prevalence in MRSA isolates.

CONCLUSIONS

A high rate of S. aureus/MRSA carriage among HCWs was observed . The presence of PVL and TSST-1 raises concern due to poor infection control compliance. Periodic screening and improved infection prevention protocols are recommended.