Aim: To characterize and analyze polymorphism of the MPT64 gene and evaluate AgMPT64-based immunochromatographic assay (ICA) specificity associated with polymorphism. Materials & methods: A total of 1449 suspected samples were tested for tuberculosis (TB), and the MPT64/rv1980c gene was sequenced using next-generation sequencing for polymorphism analysis. Results: Of the TB-positive individuals, 200 (13.80%), 186 (12.84%) and 129 (8.90%) were positive using the liquid culture, GeneXpert and fluorescence microscopy assays, respectively. Liquid culture medium-based samples were confirmed using ICA, in which 193 (96.5%) were positive while seven (3.5%) were negative. Out of 14 sequenced samples, seven were positive and seven negative; 13 were identical to the reference and just one (ICA positive) showed a C477A point mutation (F159L). Conclusion: The results indicate that AgMPT64 can be considered as a potent vaccine candidate.
Keywords: M. tuberculosis; MPT64 gene; NGS; biomarker; diagnosis; mutation; polymorphism.