Diagnosis of genitourinary tuberculosis by loop-mediated isothermal amplification based on SYBR Green I dye reaction

A multitargeted loop-mediated isothermal amplification (MT-LAMP) assay targeting mpt64 (Rv1980c) and IS6110 was designed to diagnose genitourinary tuberculosis (GUTB) cases. While assessing gel-based, hydroxynaphthol blue (HNB) and SYBR Green I MT-LAMP assays on GUTB specimens (n = 28) in a pilot study, both gel-based/SYBR Green I assays exhibited better sensitivity than HNB LAMP. Since SYBR Green MT-LAMP is easier to perform compared with a gel-based assay, a higher number of GUTB specimens (n = 55) were evaluated by SYBR Green MT-LAMP, wherein 85.5% sensitivity and 94.4% specificity (n = 36) were obtained. Moreover, the sensitivity attained by MT-LAMP was significantly higher (p < 0.05) than with multiplex-PCR (mpt64 + IS6110). After further validating these MT-LAMP data in different epidemiological settings, this assay may be developed as a diagnostic kit. METHOD SUMMARY Multitargeted loop-mediated isothermal amplification (MT-LAMP) using gel-based and hydroxynaphthol blue (HNB)/SYBR Green I dye reactions were evaluated for the diagnosis of genitourinary tuberculosis, wherein both gel-based and SYBR Green I MT-LAMP exhibited a bit better diagnostic yield than HNB dye. The utility of SYBR Green MT-LAMP was further validated in a larger number of samples. [GRAPHICS] .

Automated summary

A multitargeted loop-mediated isothermal amplification (MT-LAMP) assay targeting mpt64 (Rv1980c) and IS6110 was designed for diagnosing genitourinary tuberculosis (GUTB). The gel-based and SYBR Green I MT-LAMP assays exhibited better sensitivity compared to the HNB LAMP assay. The SYBR Green MT-LAMP assay showed a sensitivity of 85.5% and specificity of 94.4% for GUTB diagnostics.