Phages of Bacteroides (GB-124): A Novel Tool for Viral Waterborne Disease Control?

Abstract

Current fecal indicator bacteria (FIB) and emerging microbial source tracking (MST) methods may indicate the presence and even the likely source of water contamination, but they are less effective at determining the potential risk to health from human enteric viruses. This paper investigates the presence of human-specific phages (detected using a low-cost MST method) in municipal wastewaters (MW) and assesses whether they may be used effectively to screen for the likely presence of human adenovirus (HAdV) and norovirus (NoV). The findings demonstrated that all samples positive for HAdV and/or NoV also contained phages infecting Bacteroides GB-124 (mean = 4.36 log(10) PFU/100 mL) and that GB-124 phages, HAdV, and NoV were absent from samples of nonhuman origin. HAdV and NoV were detected more frequently in MW samples containing higher levels of phages (e.g., >10(2)) and FIB (e.g., >10(3)). Interestingly, at one sewage treatment works (STW), the levels of GB-124 phages present in treated MW were not significantly lower (p = 0.001) than those in untreated MW. There was a positive correlation (R = 0.42) between the size of STW and the number of GB-124 phages present in the final treated effluent. Therefore, the detection of GB-124 phages by a simple phage-lysis method may have considerable potential as a low-cost surrogate for the detection of certain human pathogenic viruses in MW and receiving waters.

Evaluation of Bacteroides fragilis GB-124 bacteriophages as novel human-associated faecal indicators in the United States

“…GB‐124 phages, however, were not detected in any of the nonhuman faecal samples analysed (Table ), which is consistent with earlier findings from the EU (Ebdon et al . , ; Ogilvie et al . ).…”

“…However, considering that phage was not detected in any nonhuman faecal samples in the EU (Ebdon et al . , ; Ogilvie et al . ) and that it was detected in more known human samples than any other viral marker tested in the California study (Harwood et al .…”

Bacteriophage removal in a full-scale membrane bioreactor (MBR) – Implications for wastewater reuse

“…Indeed, phages may be a more appropriate indicator of the presence of enteric viruses in water and wastewaters than the bacterial indicators that continue to be widely used (Jofre et al, 1986;Gantzer et al, 1998;Purnell et al, 2011;Ebdon et al, 2012;Jofre et al, 2014) et al (2013) demonstrated that reductions in levels of somatic coliphages and F-RNA specific phages were 2.7 and 1.7 log higher as a result of MBR treatment than by conventional activated sludge treatment. Zanetti et al (2010) observed that, despite the smaller diameter of F-RNA specific phages (21-30nm), their levels in the permeate were lower than those of somatic coliphages (30-100nm).…”

Thermal Inactivation of Enteric Viruses and Bioaccumulation of Enteric Foodborne Viruses in Live Oysters (Crassostrea virginica)

“…Historically, these standards (27)(28)(29)(30) have succeeded in reducing many types of shellfishrelated bacterial outbreaks; however, it has been shown that the bacterial standards are inadequate for estimating the presence of enteric viruses in shellfish and growing waters. Moreover, the depuration process for shellfish harvested from conditionally approved (or category B) growing areas has been shown to be less effective at eliminating enteric viruses than bacteria from contaminated shellfish (31)(32)(33).…”