Preliminary Evaluation of Rapid Visual Identification of Burkholderia pseudomallei Using a Newly Developed Lateral Flow Strip-Based Recombinase Polymerase Amplification (LF-RPA) System

Burkholderia pseudomallei is an important infectious disease pathogen that can cause melioidosis. Melioidosis is mainly prevalent in Thailand, northern Australia and southern China and has become a global public health problem. Early identification of B. pseudomallei is of great significance for the diagnosis and prognosis of melioidosis. In this study, a simple and visual device combined with lateral flow strip-based recombinase polymerase amplification (LF-RPA) was developed, and the utility of the LF-RPA assay for identifying B. pseudomallei was evaluated. In order to screen out the optimal primer probe, a total of 16 pairs of specific primers targeting the orf2 gene of B. pseudomallei type III secretion system (T3SS) cluster genes were designed for screening, and F1/R3 was selected as an optimal set of primers for the identification of B. pseudomallei, and parameters for LF-RPA were optimized. The LF-RPA can be amplified at 30-45 degrees C and complete the entire reaction in 5-30 min. This reaction does not cross-amplify the DNA of other non-B. pseudomallei species. The limit of detection (LOD) of this assay for B. pseudomallei genomic DNA was as low as 30 femtograms (fg), which was comparable to the results of real-time PCR. Moreover, 21 clinical B. pseudomallei isolates identified by 16S rRNA gene sequencing were retrospectively confirmed by the newly developed LF-RPA system. Our results showed that the newly developed LF-RPA system has a simple and short time of operation and has good application prospect in the identification of B. pseudomallei.