Evaluation of loop mediated isothermal amplification (LAMP) assay for rapid detection of methicillin resistant Staphylococcus aureus in Tanta University Hospitals in Egypt

Document Type : Original Article


1 Department of Medical Microbiology and Immunology, Faculty of Medicine, Tanta University, Egypt

2 Anesthesia and Surgical Intensive Care Departments, Faculty of Medicine, Tanta University, Egypt.


Background: Methicillin-resistant Staphylococcus aureus (MRSA) has a long history of being a common source of healthcare-associated infections (HAIs). Early patient treatment and effective infection control strategies depend on quick MRSA diagnosis. Aim of study: This study aimed to assess the sensitivity and specificity of loop mediated isothermal amplification (LAMP) assay for rapid detection of MRSA. Methods: A total of 200 samples from patients with HAIs have been included in this study. Each sample underwent bacteriological examination. Isolation and identification of Staphylococcus aureus (S. aureus) were done by traditional cultural methods. Methicillin susceptibility was assessed phenotypically and genotypically. The phenotypic methods included cefoxitin disc diffusion and MIC detection by oxacillin E.test, while the genotypic methods included both Real-time PCR and LAMP technique for femB and mecA genes detection. Results: Out of 200 tested samples, 55 were S. aureus by conventional phenotypic methods. Both cefoxitin disc diffusion and oxacillin E.test were able to identify methicillin resistance in (78.2%) of S. aureus isolates. femB gene was found in all S. aureus isolates 55 (100%) while mecA gene was found in 44(80%) of the isolates by both Real-time PCR and LAMP. Compared to the gold standard PCR, LAMP had sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of (100%) each. Conclusion: Combined detection of mecA and femB genes is reliable for diagnosis of MRSA. LAMP is a rapid, simple, sensitive, specific and relatively less costly assay for MRSA identification. LAMP can be considered a good substitute to PCR for MRSA detection.


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