Loop-mediated isothermal amplification (LAMP) assay targeting RLEP for detection of Mycobacterium leprae in leprosy patients

Abstract

Objective: Leprosy is a chronic infectious disease caused by Mycobacterium leprae and it remains a significant health problem in several parts of the world. Early and accurate diagnosis of this disease is therefore essential. Previously published loop-mediated isothermal amplification (LAMP) protocols for detecting mycobacterial species used conventional primers targeting the 16S rRNA, gyrB and insertion sequence genes. Methods: In this study, we conducted a LAMP assay for leprosy and compared it with quantitative polymerase chain reaction (q-PCR) and conventional PCR assays to determine the efficiency, sensitivity and specificity of each technique. We chose conserved sequence RLEP as a suitable molecular target for assays. Results: The LAMP assay provided rapid and accurate results, confirming leprosy in 91/110 clinical skin tissue samples from leprosy patients and amplifying the target pathogen in <60 min at 65 °C. The assay was more sensitive than conventional PCR and more straightforward and faster than the q-PCR assay. Conclusions: The LAMP assay has the potential for developing quicker, more accessible visual methods for the detection of M. leprae, which will enable early diagnosis and treatment and prevent further infection in endemic areas.

Keywords

• Mycobacterium leprae
• RLEP
• Leprosy
• LAMP
• Skin infections