Evaluation of stability and inactivation methods of SARS-CoV-2 in context of laboratory settings

Abstract

The novel coronavirus SARS-CoV-2 is the causative agent of the acute respiratory disease COVID-19, which has become a global concern due to its rapid spread. Laboratory work with SARS-CoV-2 in a laboratory setting was rated to biosafety level 3 (BSL-3) biocontainment level. However, certain research applications in particular in molecular biology require incomplete denaturation of the proteins, which might cause safety issues handling contaminated samples. In this study, we evaluated lysis buffers that are commonly used in molecular biological laboratories for their ability to inactivate SARS-CoV-2. In addition, viral stability in cell culture media at 4 °C and on display glass and plastic surfaces used in laboratory environment was analyzed. Furthermore, we evaluated chemical and non-chemical inactivation methods including heat inactivation, UV-C light, addition of ethanol, acetone-methanol, and PFA, which might be used as a subsequent inactivation step in the case of insufficient inactivation. We infected susceptible Caco-2 and Vero cells with pre-treated SARS-CoV-2 and determined the tissue culture infection dose 50 (TCID50) using crystal violet staining and microscopy. In addition, lysates of infected cells and virus containing supernatant were subjected to RT-qPCR analysis. We have found that guanidine thiocyanate and most of the tested detergent containing lysis buffers were effective in inactivation of SARS-CoV-2, however, the M-PER lysis buffer containing a proprietary detergent failed to inactivate the virus. In conclusion, careful evaluation of the used inactivation methods is required especially for non-denaturing buffers. Additional inactivation steps might be necessary before removal of lysed viral samples from BSL-3.

Reduced Neutralization of SARS-CoV-2 Omicron Variant by Vaccine Sera and Monoclonal Antibodies

“…All cell culture work involving infectious SARS-CoV-2 was performed under biosafety level 3 (BSL-3) conditions. Sample inactivation for further processing was performed with previously evaluated methods 10 .…”

Antibody-Mediated Neutralization of Authentic SARS-CoV-2 B.1.617 Variants Harboring L452R and T478K/E484Q

“…GenBank accession numbers for the strains used in this study are as follows: B (FFM1/2020), MT358638, [ 23 ]; B (FFM5/2020), MT358641, [ 23 ]; B.1 (FFM7/2020), MT358643, [ 23 ]; B.1.1.7 (FFM-UK7931/2021), MZ427280, [ 14 ]; B.1.427 (FFM-CAL6541/2021), MZ317895; B.1.429 (FFM-CALsprt/2021), MZ317896.2; B.1.617.1 (FFM-IND5881/2021), MZ315140; B.1.617.2 (FFM-IND8424/2021), MZ315141. All virus-containing samples were inactivated according to standardized methods as described previously [ 24 ].…”

“…GenBank accession numbers for the strains used in this study are as follows: B (FFM1/2020), MT358638, [23]; B (FFM5/2020), MT358641, [23] (FFM-IND8424/2021), MZ315141. All virus-containing samples were inactivated according to standardized methods as described previously [24].…”

Predicted and Measured Virucidal Efficacies of Microbicides for Emerging and Re-emerging Viruses Associated with WHO Priority Diseases

“…The information displayed in Table 4 considers microbicides intended for disinfection of HITES [15,26,27], inactivation in liquid suspension [15,[28][29][30][31][32][33][34][35][36][37], and microbicides intended for hand hygiene [15,27,30,31,33,35,[38][39][40][41]63] and for laboratory sample decontamination [19,34,35,37,42,43]. Additional reports on disinfection of laboratory samples which did not report results in terms of log 10 reduction in titer include the following [64,65]. The inactivation literature for SARS-CoV-2 and other coronaviruses has been reviewed extensively [66][67][68][69][70][71][72][73][74][75].…”