Methicillin-Resistant staphylococcus Aureus (Mrsa) in Clinical Samples and Nasal Screening for Mrsa Carriage among Healthy carriers in Hospital Setting
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Department of Microbiology
Abstract
Staphylococcus aureus is a Gram positive bacterium responsible for several bacterial infections. Antimicrobial resistance of S. aureusespecially methicillin-resistant S. aureus(MRSA), usually resistant to several antibiotics is a global public health problem,associated with considerable mortality and morbidity. This study investigated the susceptibility pattern of S.aureus isolates from various clinical samples and nasal swabsin the Shree Birendra hospital, Kathmandu. In addition, characterization of Methicillin-sensitive S. aureus(MSSA) and MRSA were reported to determine the current prevalence of MRSA as well as nasal carrier rate among hospital staffs and patient visitors. Characterization and identification of S. aureus was confirmed by microbiological methods and antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method. A total of 138 S. aureuswere isolated from various clinical samples. Among isolates, 18.1% were found to be MRSA. Similarly 25.0% and18.0%S. aureus nasal carrier rate was found among health personnel and patient visitor srespectively. No MRSA was found among positive isolates from healthy carriers. The higher MRSA was isolated from inpatient setting. Among MSSA isolates from clinical samples, 60.2% (68/113) were multidrug-resistant (MDR) while among MRSA isolates,more than 90.0% were MDR. In case of nasal isolates from health personnel, only 32.0%(8/25) were MDR strains. Gentamicin was found to be more effective against MSSA with93.6% sensitivity. More than 50.0% of MRSA strains from clinical samples were resistant to all antibiotics used except Vancomycin. Isolates of both clinical samples and nasal swabs showed highest resistance towards penicillin. In view of the high resistancerates of MRSA to Gentamicin, Erythromycin, Ciprofloxacin and Cotrimoxazole,treatment of MRSA infections with these antibacterial agents would be unreliable.MRSA infections are still one of the most threatening infections in the hospitals. Therefore,regular surveillance of MRSA related infections including monitoring of antimicrobial susceptibility pattern of MRSA and formulation of a definite antimicrobial policy may behelpful for reducing MRSA prevalence in hospital setting. In addition, improvement of hygiene standards in hospitals among personnel and visitors will help to prevent S.aureus and MRSA transmission.
Key words:S. aureus, MSSA, MRSA, nasal healthy carriers, MDR,Shree Birendra hospital