Establishment and Clinical Application of a RPA-LFS Assay for Detection of Capsulated and Non-Capsulated Haemophilus influenzae

Abstract

A recombinase polymerase amplification-lateral flow strip assay was established for detection of the outer membrane protein P6 (<i>omp6</i>) and the capsule encoding gene <i>bexA</i> of <i>Haemophilus influenzae</i> and the detection limit, sensitivity, and specificity were determined. Specific primers and probes were designed based on the published nucleotide sequences of <i>omp6</i> and <i>bexA</i>. The minimum detection limit was determined with standard strains and the practical applicability of the RPA-LFS assay was assessed by detection of 209 clinical samples. The results confirmed that the RPA-LFS assay was both specific and sensitive for the detection of capsulated and non-capsulated <i>H. influenzae</i> with a detection limit of 1 CFU/µL. The detection rate of the 209 clinical samples was 97.1%, while the detection rate of capsulated <i>H. influenzae</i> was 63.2%. The detection results were consistent with the traditional culture method and dual polymerase chain reaction (PCR), confirming the applicability of the RPA-LFS assay.