Prevalence of nasal colonization of methicillin-resistant Staphylococcus aureus among schoolchildren of Barabanki district, Uttar Pradesh, India.

Introduction: The study aimed to determine the prevalence of nasal colonization of methicillin-resistant Staphylococcus aureus (MRSA), the minimum inhibitory concentration (MIC) of oxacillin and vancomycin, inducible clindamycin resistance, and antimicrobial resistance pattern of S. aureus among children of Barabanki district, Uttar Pradesh, India.

Materials and Methods: School-going children of age group of 5-15 years were identified and selected according to the inclusion and exclusion criteria. Two nasal swabs were collected from each child as per the Centers for Disease Control and Prevention guidelines and transported to laboratory. Swabs were cultured on mannitol salt agar and 5% blood agar and incubated for 18-24 h at 37°C. Identification was done as per routine laboratory protocol. Detection of MRSA was done through cefoxitin 30 μg discs and D-zone test. Antibiotic susceptibility pattern of S. aureus by Kirby-Bauer disc diffusion method along with MIC for oxacillin and vancomycin was performed simultaneously according to Clinical Laboratory Standards Institute guidelines.

Results: Out of 300 children, 140 (46.67%) were found to be nasal carriage for S. aureus , among which MRSA was found to be 23 (7.67%). All S. aureus and MRSA isolates were sensitive to vancomycin with MIC <2 μg/ml, whereas 23 S. aureus were found resistant to oxacillin with MIC value >4 μg/ml. Resistance to penicillin and co-trimoxazole was highest, whereas all were sensitive to linezolid. MRSA showed 100% susceptibility to linezolid, followed by gentamicin (91.4%) and tetracycline (87%).

Conclusion: With the risk involved in transmission of infection, steps for identifying the carriers and its eradication should be carried out. Rational use of antibiotics should be given preference too.