PREVALENCE OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS AND OTHER STAPHYLOCOCCAL NASAL CARRIAGES AMONG HEALTHCARE WORKERS, PHRAMONGKUTKLAO HOSPITAL

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a group of S. aureus strains containing the SCCmec gene causing beta-lactam antibiotic resistance. MRSA is common in healthcare settings and can cause serious problems. Objective: The study aimed to investigate the prevalence of MRSA nasal colonization among privates of the Medical Private Company, Phramongkutklao Hospital, including antibiotic susceptibility pattern of S. aureus isolates and risk factors of S. aureus nasal carriage. Methods: Nasal swabs were obtained from the anterior nares of 170 privates. Staphylococcal isolates were identified using a catalase test, tube coagulase test and matrix-assisted laser desorption/ ionization time of flight mass spectrometry (MALDI-TOF MS). MRSA detection was screened using cefoxitin disk diffusion and confirmed using the mecA gene detection and SCCmec typing. Antibiotic susceptibility patterns of S. aureus were examined using the disk diffusion method. A questionnaire was collected from the subjects to determine risk factors for S. aureus nasal carriage. Results: Of 170 subjects, 157 (92.35%) revealed staphylococcal positive, yielding 161 staphylococcal isolates. The prevalence of MRSA, methicillin-resistant Staphylococcus epidermidis (MRSE), and methicillin-susceptible Staphylococcus aureus (MSSA) nasal carriage was 0.59, 1.18 and 8.82%, respectively. The MRSA isolate carried mecA revealing SCCmec type II. The MSSA isolates indicated low resistance to tetracycline (13.3%), whereas the MRSA isolate resisted ciprofloxacin, clindamycin, erythromycin, gentamicin, oxacillin and tetracycline. Using multiple logistic regression analysis, a significant risk factor for S. aureus nasal carriage was utensil sharing (adjusted odds ratio=4.41; 95% CI=1.33-14.61). Conclusion: Healthcare-associated MRSA existed among privates of the Medical Private Company. An associated risk factor for acquiring S. aureus was utensil sharing which could be used to help improve prevention and control management among privates.