Diagnostic utility of LAMP PCR targeting bcsp-31 gene for human brucellosis infection

Indian J Med Microbiol. 2023 Jul-Aug:44:100354. doi: 10.1016/j.ijmmb.2023.01.012. Epub 2023 May 11.

Abstract

Purpose: Human brucellosis is a neglected zoonotic disease of significant public health concern. Molecular diagnosis of brucella remains challenging in low resource settings, due to the high infrastructure and cost involved. Loop-mediated isothermal amplification (LAMP) is a rapid point of care polymerase chain reaction (PCR) with the utility of on-field molecular diagnosis and offers a convenient alternative to conventional PCR. In the present study, we developed and evaluated the diagnostic utility of in house LAMP PCR targeting the Brucella genus-specific bcsp-31 gene in patients having febrile illness.

Materials and methods: The analytical sensitivity and specificity of bcsp-31 LAMP PCR was first evaluated using brucella (n ​= ​8) and non-brucella cultures (n ​= ​5), along with spiked clinical samples. The overall diagnostic utility of developed LAMP PCR was then further evaluated in 393 human samples suspected of brucellosis.

Results: The developed LAMP PCR could detect as low as 8 ​fg of DNA by visual detection within 35min. We report sensitivity and specificity of the developed LAMP PCR as 90.91% and 99.37%.The accuracy of the developed test assay was found to be 98.60%. In clinical samples, LAMP gave positivity of 20% with the concordance of 89% with conventional PCR.

Conclusion: To conclude, a rapid, efficacious, sensitive LAMP PCR targeting the bcsp 31 gene was developed. The existing LAMP PCR can be used as a point of care screening test in various low resource endemic setting in lieu of conventional PCR for estimation of prevalence data, diagnosis and treatment of brucellosis.

Keywords: Human brucellosis; LAMP; PCR; bcsp 31.

MeSH terms

  • Brucella* / classification
  • Brucella* / genetics
  • Brucellosis* / diagnosis
  • Brucellosis* / epidemiology
  • Brucellosis* / microbiology
  • Genes, Bacterial*
  • Humans
  • Limit of Detection
  • Molecular Diagnostic Techniques / standards
  • Point-of-Care Testing / standards
  • Polymerase Chain Reaction* / methods
  • Polymerase Chain Reaction* / standards
  • Prevalence
  • Reference Standards
  • Sensitivity and Specificity
  • Time Factors
  • Zoonoses / diagnosis
  • Zoonoses / epidemiology
  • Zoonoses / microbiology