Comparative analysis of rapid concentration methods for the recovery of SARS-CoV-2 and quantification of human enteric viruses and a sewage-associated Lachno3 marker gene in untreated wastewater

Ahmed, Warish; Bivins, Aaron; Simpson, Stuart L.; Smith, Wendy J.M.; Metcalfe, Suzanne; McMinn, Brian; Symonds, Erin M.; Korajkic, Asja

To support public-health-related disease surveillance and monitoring, it is crucial to concentrate both enveloped and non-enveloped viruses from domestic wastewater. To date, most concentration methods were developed for non-enveloped viruses, and limited studies have directly compared the recovery efficiency of both types of viruses. In this study, the effectiveness of two different concentration methods (Concentrating Pipette Select™ (CP) method—than the adsorption-extraction (AE) method amended with MgCl2) was evaluated for untreated wastewater matrices using three different viruses (SARS-CoV-2 (seeded), human adenovirus 40/41 (HAdV 40/41), enterovirus (EV) and a wastewater-associated bacterial marker gene targeting Lachnospiraceae (Lachno3). The most effective concentration method varied by microbial analyte. For SARS-CoV-2, the estimated mean recovery efficiencies were statistically significantly greater (p < 0.05) by as much as 5.46 times, using the CP method—than the AE method amended with MgCl2. SARS-CoV-2 RNA recovery was greater for samples with higher titer seeds regardless of the method, and the estimated mean recovery efficiencies using the CP method were 25.1 ± 11% across ten WWTPs when wastewater samples were seeded with 5 × 104 gene copies (GC) of SARS-CoV-2. Meanwhile, the AE method significantly (p < 0.05) yielded greater concentrations of indigenous HAdV 40/41 and Lachno3 from wastewater compared to the CP eluate method. Finally, no statistically significant (p > 0.05) differences in indigenous EV concentrations were identified in comparing the AE and CP eluate methods. These data indicate that the most effective concentration method varies by microbial analyte and that the priorities of the surveillance or monitoring program should be considered when choosing the concentration method.