Evaluation of two rapid ultrafiltration-based methods for SARS-CoV-2 concentration from wastewater

Quantitative measurements of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in raw wastewater have been implemented worldwide since the beginning of the pandemic. Recent efforts are being made to evaluate different viral concentration methodologies to overcome supplier shortages during lockdowns. A set of 22-wastewater samples seeded with marine hepatitis virus (MHV), a member of the Coronaviridae family, and the bacteriophage MS2, were used to characterize and compare two ultrafiltration-based methods: a centrifugal ultrafiltration device (Centricon (R) Plus-70) and the automated concentrating pipette CP-Select (TM). Based on the recovery efficiencies, significant differences were observed for MHV, with Centricon (R) Plus-70 (24%) being the most efficient method. Nevertheless, concentrations of naturally occurring SARS-CoV-2, Human adenoviruses and JC polyomaviruses in these samples did not result in significant differences between methods suggesting that testing naturally occurring viruses may complement the evaluation of viral concentration methodologies. Based on the virus adsorption to solids and the necessity of a pre-centrifugation step to remove larger particles and avoid clogging when using ultrafiltration methods, we assessed the percentage of viruses not quantified after ultrafiltration. Around 23% of the detected SARS-CoV-2 would be discarded during the debris removal step. The CP-Select (TM) provided the highest concentration factor (up to 333x) and the lowest LAO (6.19 x 10(3) GC/l) for MHV and proved to be fast, automatic, highly reproducible and suitable to work under BSL-2 measures. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Quantitative measurements of SARS-CoV-2 in raw wastewater have been widely conducted since the pandemic, with efforts to evaluate different viral concentration methods to address supplier shortages. The study found significant differences in efficiency between two ultrafiltration-based methods for seeded viruses, while naturally occurring viruses showed no significant differences, suggesting the importance of testing both to evaluate concentration methods. The CP-Select (TM) method provided the highest concentration factor and proved to be fast, automatic, and suitable for working under BSL-2 measures.