Investigation of enteric adenovirus and poliovirus removal by coagulation processes and suitability of bacteriophages MS2 and φX174 as surrogates for those viruses

Abstract

We evaluated the removal of enteric adenovirus (AdV) type 40 and poliovirus (PV) type 1 by coagulation, using water samples from 13 water sources for drinking water treatment plants in Japan. The behaviors of two widely accepted enteric virus surrogates, bacteriophages MS2 and φX174, were compared with the behaviors of AdV and PV. Coagulation with polyaluminum chloride (PACl, basicity 1.5) removed AdV and PV from virus-spiked source waters: the infectious AdV and PV removal ratios evaluated by means of a plaque-forming-unit method were 0.1-1.4-log10 and 0.5-2.4-log10, respectively. A nonsulfated high-basicity PACl (basicity 2.1) removed infectious AdV and PV more efficiently than did other commercially available PACls (basicity 1.5-2.1), alum, and ferric chloride. The MS2 removal ratios tended to be larger than those of AdV and PV, partly because of differences in the hydrophobicities of the virus particles and the sensitivity of the virus to the virucidal activity of PACl; the differences in removal ratios were not due to differences in the surface charges of the virus particles. MS2, which was more hydrophobic than the other viruses, was inactivated during coagulation with PACl. Therefore, MS2 does not appear to be an appropriate surrogate for AdV and PV during coagulation. In contrast, because φX174, like AdV and PV, was not inactivated during coagulation, and because the hydrophobicity of φX174 was similar to or somewhat lower than the hydrophobicities of AdV and PV, the φX174 removal ratios tended to be similar to or somewhat smaller than those of the enteric viruses. Therefore, φX174 is a potential conservative surrogate for AdV and PV during coagulation. In summary, the surface hydrophobicity of virus particles and the sensitivity of the virus to the virucidal activity of the coagulant are probably important determinants of the efficiency of virus removal during coagulation.

Near Real-Time Flow Cytometry Monitoring of Bacterial and Viral Removal Efficiencies during Water Reclamation Processes

“…Studies have shown that some coagulants are toxic to viruses, although the virucidal effect varies among different types of viruses. Bacteriophage MS2 was found to be more sensitive to polyaluminum chloride than enteric adenoviruses and poliovirus [19]. Thus, MS2, as a traditional surrogate virus, may not properly represent the fate of enteric viruses during the coagulation/sedimentation process.…”

Evaluation of the suitability of a plant virus, pepper mild mottle virus, as a surrogate of human enteric viruses for assessment of the efficacy of coagulation–rapid sand filtration to remove those viruses

“…AdV type 40 Dugan strain (ATCC VR-931), CV B5 Faulkner strain (ATCC VR-185), HAV IB HM175/18f strain (ATCC VR-1402), and MNV type 1 CW1 strain (ATCC PTA-5935) were obtained from the American Type Culture Collection (ATCC, Manassas, VA, USA) and propagated in human lung carcinoma epithelial cells (A549 cells; ATCC CCL-185, obtained from ATCC), buffalo green monkey kidney epithelial cells (BGM cells; kindly supplied by Dr. Daisuke Sano, Hokkaido University, Sapporo, Japan), fetal rhesus monkey kidney epithelial cells (FRhK-4 cells; ATCC CRL-1688, obtained from ATCC), and murine macrophage cells (RAW264.7 cells; ATCC TIB-71, obtained from ATCC), respectively. Details of the propagation and purification of AdV, CV, HAV, and MNV have been described in previous reports (Shirasaki et al, 2016;Shirasaki et al, 2017a).…”

“…The concentrations of AdV, CV, HAV, and MNV in the purified solutions were approximately 10 5-6 , 10 7 , 10 5-6 , and 10 6 plaque-forming units (PFU)/mL, respectively, based on the results of plaque assays (Shirasaki et al, 2016;Shirasaki et al, 2017a).…”

“…F-specific RNA bacteriophage MS2 (NBRC 102619) and somatic DNA bacteriophage φX174 (NBRC 103405) were obtained from the National Institute of Technology and Evaluation Biological Research Center (Kisarazu, Japan), as were the Escherichia coli bacterial hosts in which the bacteriophages were propagated (NBRC 13965 for MS2, NBRC 13898 for φX174). Details of the propagation and purification of the bacteriophages have been described by Shirasaki et al (2016). The concentrations of MS2 and φX174 in the purified solutions were approximately 10 10 and 10 7-8 PFU/mL, respectively, as evaluated by means of plaque assays (Shirasaki et al, 2016).…”

“…Details of the propagation and purification of the bacteriophages have been described by Shirasaki et al (2016). The concentrations of MS2 and φX174 in the purified solutions were approximately 10 10 and 10 7-8 PFU/mL, respectively, as evaluated by means of plaque assays (Shirasaki et al, 2016).…”