Rapid detection of Burkholderia pseudomallei with a lateral flow recombinase polymerase amplification assay

PLoS One. 2019 Jul 8;14(7):e0213416. doi: 10.1371/journal.pone.0213416. eCollection 2019.

Abstract

Melioidosis is a severe infectious disease caused by gram-negative, facultative intracellular pathogen Burkholderia pseudomallei (B. pseudomallei). Although cases are increasing reported from other parts of the world, it is an illness of tropical and subtropical climates primarily found in southeast Asia and northern Australia. Because of a 40% mortality rate, this life-threatening disease poses a public health risk in endemic area. Early detection of B. pseudomallei infection is vital for prognosis of a melioidosis patient. In this study, a novel isothermal recombinase polymerase amplification combined with lateral flow dipstick (LF-RPA) assay was established for rapid detection of B. pseudomallei. A set of primer-probe targeting orf2 gene within the putative type III secretion system (T3SS) cluster genes was generated and parameters for the LF-RPA assay were optimized. Result can be easy visualized in 30 minutes with the limit of detection (LOD) as low as 20 femtogram (fg) (ca. 25.6 copies) of B. pseudomallei genomic DNA without a specific equipment. The assay is highly specific as no cross amplification was observed with Burkholderia mallei, members of the Burkholderia cepacia-complex and 35 non-B. pseudomallei bacteria species. Moreover, isolates from patients in Hainan (N = 19), Guangdong (N = 1), Guangxi (N = 3) province of China as well as in Australia (N = 3) and Thailand (N = 1) were retrospectively confirmed by the newly developed method. LODs for B. pseudomallei-spiked soil and blood samples were 2.1×103 CFU/g and 4.2×103 CFU/ml respectively. The sensitivity of the LF-RPA assay was comparable to TaqMan Real-Time PCR (TaqMan PCR). In addition, the LF-RPA assay exhibited a better tolerance to inhibitors in blood than TaqMan PCR. Our results showed that the LF-RPA assay is an alternative to existing PCR-based methods for detection of B. pseudomallei with a potentiality of early accurate diagnosis of melioidosis at point of care or in-field use.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Bacterial Typing Techniques / economics
  • Bacterial Typing Techniques / methods
  • Burkholderia pseudomallei / genetics
  • Burkholderia pseudomallei / isolation & purification*
  • DNA Primers / genetics
  • DNA, Bacterial / analysis*
  • DNA, Bacterial / genetics
  • Humans
  • Limit of Detection
  • Melioidosis / blood
  • Melioidosis / diagnosis*
  • Melioidosis / microbiology
  • Nucleic Acid Amplification Techniques / economics
  • Nucleic Acid Amplification Techniques / methods*
  • Recombinases / chemistry
  • Soil Microbiology
  • Time Factors

Substances

  • DNA Primers
  • DNA, Bacterial
  • Recombinases

Grants and funding

This study was supported by grant of Development of Capacity for Pathogen Detection Projects (131031102000150003) from the National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC), Changping, Beijing, 102206 China. BK received the funding. URL: http://www.icdc.cn. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.