The use of bacteriophage MS2 for the development and application of a virucide decontamination test method for porous and heavily soiled surfaces

Abstract

Aims: (i) To develop an analytical method for recovery and quantification of bacteriophage MS2-as a surrogate for foot-and-mouth disease virus-from complex porous surfaces, with and without the presence of laboratorydeveloped agricultural grime; (ii) to evaluate, with a 4-log dynamic range, the virucidal activity of common biocides for their ability to decontaminate surfaces and hence remediate facilities, following a foreign animal disease contamination incident. Methods and Results: An analytical method was developed and optimized for MS2 recovery from simulated agricultural surfaces. The addition of Dey-Engley neutralizing broth to an extraction buffer improved MS2 viability in liquid extracts, with optimal analytical holding times determined as <8 to ≤24 h, depending on matrix. The recovery of MS2 from surface materials decreased in the order: nonporous reference material >grimed porous materials >nongrimed porous materials. In disinfectant testing, two spray applications of pAB were effective against MS2 (≥4-log reduction) on all operational-scale materials. Two per cent citric acid had limited effectiveness, with a ≥4-log reduction observed on a selected subset of grimed concrete samples. Conclusions: Decontamination efficacy test results can be affected by surface characteristics, extraction buffer composition, analytical holding time and surface-specific organism survivability. Efficacy should be evaluated using a test method that reflects the environmental characteristics of the intended application. Significance and Impact of the Study: The results of this study demonstrate the importance of analytical method verification tests for disinfectant testing prior to application in complex environments.

Microwave-Generated Steam Decontamination of N95 Respirators Utilizing Universally Accessible Materials

“…Unlike SARS-CoV-2, the MS2 phage lacks a lipid envelope, making it more resistant to disinfection. Due to its stability, MS2 has been used to model disinfection of viruses such as norovirus and Ebola virus (8,9).…”

Microwave-Generated Steam Decontamination of N95 Respirators Utilizing Universally Accessible Materials

“…After minute of microwave steam decontamination, we saw no significant difference in MS2 phage reduction between the two methods ( Figure 1B). It is important to note that both methods resulted in greater than a 4-log 10 To identify the optimal length of microwave time required for MS2 phage decontamination, we performed a dose-response test using 1 minute increments where we examined the decontamination of 10 7 PFU of MS2 on 1cm 2 N95 coupons placed over an open mug (as described above). Following three minutes of microwave steam treatment there were no detectable MS2 phage remaining on the coupons (Figure 2A).…”

“…As described above, we inoculated ten sections of an N95 respirator with MS2 phage and treated the respirator for 3 minutes over the container system ( Figure 3D). Only 20% of the sampled sections exhibited residual phage, and of those, each exhibited a 5-log 10 Since it is essential that any decontamination method not reduce the filtration or integrity of N95 respirators, we examined N95 respirator fit and function after sequential treatments. After 1, 5 or 20 three-minute treatment cycles, no damage was evident in the integrity of the respirators or their component parts (i.e.…”

Recovery and chemical disinfection of foot-and-mouth disease and African swine fever viruses from porous concrete surfaces

“…For example, Calfee and Wendling (2013) reported statistically significant differences in the recovery of vegetative bacteria from several porous coupon materials, with concrete and wood having the lowest recovery values. Additionally, Wood et al (2010) were unsuccessful in recovering viable, highly pathogenic avian influenza virus from concrete coupons by multiple extraction methods.…”

“…2003, Springthorpe and Sattar 2005, ASTM 2017), and success is dependent upon sufficient recovery of microorganisms from untreated, positive control coupons (Wyrzykowska‐Ceradini et al . 2019). Insufficient recovery (<4‐log 10 ) of viable virus from control coupons precludes demonstrating the minimum 4‐log 10 reduction in infectious titre required for virucidal efficacy determination and subsequent product registration with the U.S. Environmental Protection Agency (US EPA 1981).…”