Development of a loop-mediated isothermal amplification (LAMP) method for specific detection of Mycobacterium bovis

PLoS Negl Trop Dis. 2021 Jan 25;15(1):e0008996. doi: 10.1371/journal.pntd.0008996. eCollection 2021 Jan.

Abstract

Bovine tuberculosis (TB) caused by Mycobacterium bovis is a significant health threat to cattle and a zoonotic threat for humans in many developing countries. Rapid and accurate detection of M. bovis is fundamental for controlling the disease in animals and humans, and for the proper treatment of patients as one of the first-line anti-TB drug, pyrazinamide, is ineffective against M. bovis. Currently, there are no rapid, simplified and low-cost diagnostic methods that can be easily integrated for use in many developing countries. Here, we report the development of a loop-mediated isothermal amplification (LAMP) assay for specific identification of M. bovis by targeting the region of difference 4 (RD4), a 12.7 kb genomic region that is deleted solely in M. bovis. The assay's specificity was evaluated using 139 isolates comprising 65 M. bovis isolates, 40 M. tuberculosis isolates, seven M. tuberculosis complex reference strains, 22 non-tuberculous mycobacteria and five other bacteria. The established LAMP detected only M. bovis isolates as positive and no false positives were observed using the other mycobacteria and non-mycobacteria tested. Our LAMP assay detected as low as 10 copies of M. bovis genomic DNA within 40 minutes. The procedure of LAMP is simple with an incubation at a constant temperature. Results are observed with the naked eye by a color change, and there is no need for expensive equipment. The established LAMP can be used for the detection of M. bovis infections in cattle and humans in resource-limited areas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Humans
  • Molecular Diagnostic Techniques / methods*
  • Mycobacterium bovis / genetics
  • Mycobacterium bovis / isolation & purification*
  • Nucleic Acid Amplification Techniques / methods*
  • Sensitivity and Specificity

Supplementary concepts

  • LAMP assay

Grants and funding

This work was supported in part by a grant from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (MEXT) for the Joint Research Program of the Research Center for Zoonosis Control, Hokkaido University (to YS), and in part by Japan Agency for Medical Research and Development (AMED) under Grant Number JP20jk0210005, JP20jm0110021, JP20wm0125008 to YS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.