A CRISPR/Cas12a-based DNAzyme chemiluminescence platform for rapid detection of all Streptococcus suis and individually S. suis serotypes 7 and 9.

Streptococcus suis is a zoonotic pathogen that can infect pigs and humans with causing meningitis, sepsis, endocarditis, and arthritis. S. suis serotypes 7 and 9 cause substantial economic losses to the swine industry and pose a major threat to public health, thus, accurate and rapid detection is important for the prevention and control of epidemic disease. In this study, we developed a platform, combining recombinase polymerase amplification (RPA) with a CRISPR/Cas12a detection system to rapidly detect all S. suis serotypes and individually differentiates serotypes 7 and 9. This was achieved by targeting recN of S. suis and serotype-specific cpsH genes of serotypes 7 and 9, respectively. Both fluorescence and G4 DNAzyme chemiluminescence visualization biosensing methods had high specificity and sensitivity, no cross-reaction was found with common pig pathogens, closely related Streptococcus spp., or other S. suis serotypes. Compared to traditional identification techniques, these two methods are rapid and convenient. Notably, the G4 DNAzyme chemiluminescence method provides a clear, direct visual interpretation of results without the need for specialized equipment, which is particularly advantageous for point-of-care testing. Thus, this platform has the potential to significantly enhance diagnostic capabilities and ultimately benefit both animal and public health.