Rapid Visual Detection of Streptococcus suis and Actinobacillus pleuropneumoniae Through Duplex Recombinase Polymerase Amplification Combined with Lateral Flow Dipsticks

Primers and corresponding probes were designed for the glutamate dehydrogenase (gdh) gene of Streptococcus suis and the ApxIV gene of Actinobacillus pleuropneumoniae to establish a dual recombinant enzyme polymerase amplification (RPA)-lateral flow dipstick (LFD) detection method for the simultaneous rapid identification of S. suis and A. pleuropneumoniae. The specificity test showed that the amplification results for other pathogens were all negative, indicating that the method exhibited good specificity. The sensitivity test showed that the lowest nucleic acid concentration detectable with this method was 10(-5) ng/mu L, which was significantly higher than that observed with PCR and basic RPA. The results showed that this method detected all reference strains and clinical isolates, which was consistent with the PCR detection results. Among the 45 clinical samples, 19 cases of S. suis, 1 case of A. pleuropneumoniae and no mixed infections were detected. The detection rate was higher than that observed with bacterial isolation and the conventional PCR method, which indicated that this method is very practical and suitable for the rapid clinical detection of S. suis and A. pleuropneumoniae. Compared with the traditional method, the dual RPA-LFD method has several advantages, including high specificity, high sensitivity, fast speed and minimal requirement of instruments and equipment. In addition, the method can achieve the synchronous and rapid detection of S. suis and A. pleuropneumoniae and is helpful for the preliminary screening of clinical diseases.

Automated summary

A dual recombinant enzyme polymerase amplification (RPA)-lateral flow dipstick (LFD) detection method was established for the rapid identification of S. suis and A. pleuropneumoniae. The method exhibited good specificity and high sensitivity, making it suitable for preliminary screening of clinical diseases.