Detection of Methicillin-Resistant Staphylococcus Aureus from Clinical Samples by CHROMagar TM and the in Vitro Effect of Topical Antiseptics

Abstract

Background: Rapid identification of MRSA isolates is mandatory to control its spread and management as well, especially with the continuous emergence of antimicrobial resistance. Objectives: Our study aimed to compare the sensitivity and specificity of chromagar TM in the detection of MRSA isolates in comparison to conventional bacteriological diagnostic methods. Testing the effect of some local antiseptics (Acetic acid, povidone iodine, hydrogen peroxide and diluted sodium hypochlorite) on identified MRSA isolates was also performed to examine for increased resistance in comparison to currently used concentrations. Methodology: Ninety-five samples were collected. MRSA was identified using conventional bacteriological methods along with chromogenic agar. Bactericidal concentrations of commonly used antiseptics were determined for isolated MRSA from patients. Results: Our study revealed 100% sensitivity, specificity, PPV and NPV of cefoxitin disc diffusion method versus 93.8% sensitivity, 100% specificity, 100% PPV and 97% NPV of chromogenic agar in the identification of MRSA. All MRSA isolates were killed at 5%, 10%, 5% and 0.25% concentrations of acetic acid, povidone iodine, hydrogen peroxide and Dakin’s solution respectively. Conclusion: CHROMagar TM can be used as a rapid method for MRSA screening. The use of Hydrogen peroxide 2.5% and betadine 10% in wound management are recommended for use than Dakin’s solution and acetic acid.