A rapid and efficient protocol for simple concentration of SARS-CoV-2 from sewage.

CENTRON DANIELA

JOURNAL OF VIROLOGICAL METHODS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2021

0166-0934

The aim of this study was to set up a simple protocol to concentrate SARS-CoV-2 from sewage, which can be implemented in laboratories with minimal equipment resources. The method avoids the need of extensive purification steps and reduces the concentration of potential inhibitors of RT-qPCR contained in sewage. The concentration method consists in a single step, in which a small volume of sewage sample is incubated with polyaluminum chloride (PAC). Virus particles adsorbed to the precipitate are collected by low-speed centrifugation, after which the recovered pellet is resuspended with a saline buffer. The PAC concentration method produced an average shift of 4,4-units in Cq values compared to non-concentrated samples, indicating a 25-fold increase in detection sensitivity. The lower detection limit corresponded approximately to 100 copies per ml. Kappa index indicated substantial agreement between PAC and PEG precipitation protocols (k=0.688, CI 0.457-0.919). PAC concentrated samples can be processed immediately for RNA purification and qPCR or sent refrigerated to a diagnosis center, where SARS-CoV-2 detection should be performed in the same way as for clinical samples. This low cost protocol could be useful to aid in the monitoring of community circulation of SARS-CoV-2, especially in low- and middle-income countries, which do not have massive access to support from specialized labs for sewage surveillance.