prevalence of nasal carriage methicillin-resistant staphylococcus aureus in hospitalized patients

ABSTRACT

To determine the nasal colonization of methicillin-resistant Staphylococcus aureus in hospitalized patients. This descriptive study was carried out on 100 hospitalized patients at Shahid Beheshti Hospital in Kashan in 2007. The nasal samples were collected by sterile swabs, and transferred to Brain Heart infusion [BHI] culture medium and immediately refered to the microbiology lab in Kashan University of Medical Sciences. Samples were inoculated on blood agar and manitol salt agar media. Identification of the isolates was done by standard biochemical tests. Oxacillin susceptibilities of S. aureus isolates were determined using Mueller-Hinton oxacillin agar screen plate. The results were analyzed statistically by chi Square and Fischer's exact tests. The prevalence of nasal carriage of Staphylococcus aureus and MRSA were 38% [38 out of 100], and 52.6% [20 out of 38], respectively. The results showed that by urinary tract catheterization [P=0.005], administration of any antibiotic [p=0.008], history of diabetes mellitus [p=0.0303], and hospitalization time more than one week [p=0.0009] were the main predisposing factors for nasal colonization of MRSA. The ICU ward was the principle ward of nasal colonization by both Staphylococcus aureus [75%] and MRSA [100%], followed by infectious diseases ward with rates of 64.7% and 75%, respectively. The overall colonization rate of MRSA in the hospitalized patients in this study was high. A systematic selective screening of patients with high risk of carriage should be fruitful to implement barrier precautions and reduce cross-transmission