Development of a recombinase-aided amplification assay for rapid detection of the human pathogen Nocardia farcinca

Abstract

Nocardia farcinica, one of the most common etiological pathogens of nocardiosis in pulmonary infection, usually causes severe disseminated diseases in immunocompromised individuals. To date, there is a lack of rapid and reliable diagnostic tools for the detection of N. farcinica in clinical laboratories. In the present study, we reported the development of rapidity, simplicity, and high specificity real-time fluorescence recombinase-aided amplification (RT-RAA) assay for the detection of N. farcinica. RT-RAA technique was developed to amplify the specific gene of pbr1 and detected double labeled amplicons within 20 min by designing a specific labeled primer set and the corresponding probe. We identified 86 strains of N. farcinica and 46 closely related strains, analyzed the specificity of the developed assay, and estimated the clinical diagnostic efficacy of the method with simulated sputum samples. The results showed no cross-reaction was observed and specificity was 100%. The limit of detection of RT-RAA was 10 copies per reaction of Nocardia genomic DNA, which was up to 10 times higher sensitivity than conventional real-time quantitative PCR. In conclusion, the recombinase-mediated isothermal amplification technique is a fast, simple, and sensitive method for the detection of N. farcinica, which may have potential application for the detection of N. farcinica in clinical laboratories, especially in resource-poor areas.

Imaging Hyperspectral Feature Fusion for Estimation of Rapeseed Pod’s Water Content and Recognition of Pod’s Maturity Level

“…Traditional desiccation-based techniques for quantifying rapeseed pod pericarp water content [9][10][11] are not only time-consuming and labor-intensive but also destructive, precluding their effective integration with remote sensing technologies for rapid and accurate assessment across large-scale cultivation areas. Conventionally, the determination of optimal harvest timing has heavily relied on empirical observations, such as the visual cue of field-wide pod yellowing resembling loquat fruits or pericarp water contents ranging between 11 and 13% [12].…”