Screening for methicillin-resistant Staphylococcus aureus carriers among individuals exposed and not exposed to the hospital environment and their antimicrobial sensitivity pattern

Abstract

Aims: This study evaluated the influence of exposure to the hospital environment on methicillin-resistant Staphylococcus aureus (MRSA) carriage. The antibiograms of the MRSA isolates were examined. Materials and Methods: Nasal, throat, and web-space swabs were collected from 119 nursing students of the age group 18-23 years (exposed group) and 100 age-matched pharmacy students (nonexposed group). S. aureus was identified and antibiogram obtained as per Clinical and Laboratory Standards Institute (CLSI) guidelines. MRSA was detected by cefoxitin disc diffusion test and by growth on oxacillin screen agar as per CLSI guidelines. The presence of the mecA gene was confirmed by conventional polymerase chain reaction. Results: The MRSA carrier rates were 11.8% and 4% in the exposed and nonexposed groups, respectively. Association of exposure to the hospital environment with MRSA colonization was statistically significant. All MRSA isolates showed sensitivity to netilmicin, linezolid, tetracycline, vancomycin and teicoplanin. Among the exposed group, 71.4% MRSA isolates were resistant to ciprofloxacin, 64.3% to cotrimoxazole, 64.3% to erythromycin, 28.6% to gentamicin and 21.4% to clindamycin. Among the nonexposed group, 75% MRSA isolates were resistant to ciprofloxacin, 25% to cotrimoxazole, 25% to erythromycin, 25% to gentamicin and 25% to clindamycin. Conclusion: Exposure to the hospital environment was found to be a significant risk factor for MRSA carriage. Hospital-acquired MRSA (HA-MRSA) isolates showed greater resistance toward antimicrobials compared with community-acquired MRSA (CA-MRSA) isolates. This highlights the need for the appropriate institution of pharmacotherapy in cases of HA-MRSA and CA-MRSA infections and control of transmission by carriers.