Rapid Isothermal Detection of Pathogenic Clostridioides difficile Using Recombinase Polymerase Amplification

Abstract

Nosocomial-associated diarrhea due to Clostridioides difficile infection (CDI) is diagnosed after sample precultivation by the detection of the toxins in enzyme immunoassays or via toxin gene nucleic acid amplification. Rapid and direct diagnosis is important for targeted treatment to prevent severe cases and recurrence. We developed two singleplex and a one-pot duplex fluorescent 15 min isothermal recombinase polymerase amplification (RPA) assays targeting the toxin genes A and B (tcdA and tcdB). Furthermore, we adapted the singleplex RPA to a 3D-printed microreactor device. Analytical sensitivity was determined using a DNA standard and DNA extracts of 20 C. difficile strains with different toxinotypes. Nineteen clostridial and gastrointestinal bacteria strains were used to determine analytical specificity. Adaptation of singleplex assays to duplex assays in a 50 μL volume required optimized primer and probe concentrations. A volume reduction by one-fourth (12.4 μL) was established for the 3D-printed microreactor. Mixing of RPA was confirmed as essential for optimal analytical sensitivity. Detection limits (LOD) ranging from 119 to 1411 DNA molecules detected were similar in the duplex tube format and in the singleplex 3D-printed microreactor format. The duplex RPA allows the simultaneous detection of both toxins important for the timely and reliable diagnosis of CDI. The 3D-printed reaction chamber can be developed into a microfluidic lab-on-a-chip system use at the point of care.

Review on Microreactors for Photo-Electrocatalysis Artificial Photosynthesis Regeneration of Coenzymes

“…Food safety detection using a microreactor has the advantages of high sensitivity, high specificity, high stability, high accuracy, easy carrying, low time consumption, and low cost. Microreactors have achieved excellent application results in food safety detection for Salmonella , Clostridioids , mycotoxins, and pesticide residues [ 113 , 114 , 115 ]. Chen et al prepared a microreactor by immobilizing acetylcholinesterase on the inner wall of the capillary with a coating layer of dopamine, which can be used to stably determine organophosphorus pesticide residues in fruits and vegetables [ 116 ].…”