Detection of Methicillin Resistant Staphylococcus aureus (MRSA) from Hospital Instruments

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is a threat to both hospitalized patients and the community. This work aimed at detecting MRSA from commonly used hospital instruments. It is a descriptive hospital-based study, and 74 samples were randomly collected from swabbed instruments from five hospitals in Kano, Nigeria. Staphylococcus aureus isolates were identified by culture and biochemical tests. Susceptibility tests were carried out using the disc agar diffusion method, and MRSA was detected phenotypically using cefoxitin 30 μg discs. Also, mecA and blaZ genes were detected from some of the samples. A total of 33/74 (44.5%) isolates were identified as S. aureus, with 16/33 (48.5%) being MRSA. The results further revealed that invasive hospital instruments had the highest number of S. aureus and MRSA isolates of 18/33 (54.5%) and 11/16 (68.8%) respectively, while instruments used for superficial assessment of patient bodies had the least number of S. aureus and MRSA isolates of 6 (18.2%) and 2 (12.5%) respectively. Ciprofloxacin had the greatest activity on the isolates ranging from 75% to 100%, followed by ofloxacin (71.4% to 100%) and gentamicin (66.67% to 90.9%) respectively. The greatest level of resistance was observed with ceftazidime (33.3% to 75%), followed by cefoxitin (33.3% to 72.75%), and ceftriaxone (33.3% to 66.7%). Furthermore, the 16 MRSA isolates were generally resistant to the beta-lactam antibiotics used, with 7/16 (44%) being multi-drug resistant. Also, 2/10 (20%) and 4/10 (40%) of the MRSA isolates were positive for mecA and blaZ genes, respectively. The study detects a high level of contamination of hospital instruments and recommends strict adherence to aseptic procedures and regular screening of hospital workers for the presence of MRSA to control colonization and infection. Further studies are also needed to define the optimum use of ciprofloxacin and gentamicin against MRSA infection.