Comparative evaluation of heating instruments for detecting <i>Bacteroides</i> HF183, SARS-CoV-2, and Aichi virus A in untreated wastewater using colorimetric LAMP

This study assessed the accuracy, field suitability, and cost-effectiveness of colorimetric LAMP (c-LAMP) assays using six heating instruments: Electric Kettle, Water Bath, Heating Block, miniPCR, Thermocycler, and Genie® III. Bacteroides HF183 (HF183), SARS-CoV-2, and Aichi virus A (AiV-A) were tested using control materials and wastewater samples, comparing cLAMP with qPCR/RT-qPCR detection. qPCR/RT-qPCR reliably detected HF183 and AiV-A genetic fragments at dilutions as low as 1 × 10^-5 pg/μL, corresponding to 1.24 and 1.49 log₁₀ GC/reaction. cLAMP/RT-cLAMP detected these fragments at 1 × 10^-4 pg/μL (2.28 and 2.63 log₁₀ GC/reaction), though Electric Kettle, miniPCR, and Genie® III occasionally produced false negatives. RT-qPCR reliably detected SARS-CoV-2 fragments at 1 × 10⁰ GC/μL (1.86 log₁₀ GC/reaction), with cLAMP/RT-cLAMP performing similarly across most instruments except Thermocycler. No significant differences (p > 0.05) were observed among instruments, though inconsistencies appeared at lower concentrations. The findings offer valuable insights into heating instrument performance for cLAMP/RT-cLAMP assays, guiding their application in wastewater-based pathogen detection.