Development of a real-time recombinase polymerase amplification assay for rapid detection of Aeromonas hydrophila

Aeromonas hydrophila is ubiquitous in the aquaculture industry and a constant cause of severe disease and economic losses. The early diagnosis of these infections is crucial for disease surveillance and prevention. We developed a real-time recombinase polymerase amplification (real-time RPA) assay for detection of A. hydrophila using the haemolysin gene. The assay was performed at 37°C for 20 min and was highly specific with no cross-reaction with other fish pathogens or with other Aeromonas species. The assay detection limit was 10² copies of the Aeromonas hydrophila per reaction. Compared with traditional culture-based method or real-time PCR, the diagnostic sensitivity and specificity of the real-time RPA were 73.7 and 100%, as well as 64.7 and 93%. Our newly developed real-time RPA was specific and sensitive and can be used in large-scale and point-of-care field investigations of A. hydrophila infections to enable earlier diagnoses.