Assessment of Nucleic Acid Extraction Kits for SARS-CoV-2 Surveillance in Wastewater Samples

Objective: The aim of this study is to evaluate the effectiveness of three commercial nucleic acid extraction kits (kit A, B and C) in isolating SARS-CoV-2 viral RNA from wastewater samples. Method: In this study, water samples were collected in March 2021 from three wastewater treatment plants located in different parts of Istanbul, and it was confirmed that they were negative for SARS-CoV-2. Different concentrations of the SARS-CoV-2 virus, previously inactivated at the BSL-3 laboratory of the Pendik Veterinary Control Institute, were added to the wastewater samples. RNA extraction and quantification were performed using commercial nucleic acid extraction kits and and RT-qPCR kit specific to SARS-CoV-2. Results: At the end of the study, it was determined that kit C yielded the highest total RNA and produced more consistent results, significantly outperforming the other two kits in terms of RNA yield and purity. Statistical analysis revealed significant differences in RNA concentrations (p < 0.05) and gene copy numbers (p < 0.01) between the kits, and kit C demonstrated superior linearity and reproducibility. Conclusion: According to the findings, although all three evaluated kits are suitable for detecting SARS-CoV-2 RNA in wastewater samples, kit C provides the most efficient and reliable performance, especially for high-throughput studies. Additionally, this study highlights the importance of selecting appropriate nucleic acid extraction methods for wastewater surveillance, which serves as an early warning system for outbreaks that threaten public health.