Bacteriophages as indicators of faecal pollution and enteric virus removal

Abstract

Significance and Impact of the Study: Bacteriophage are alternative fecal indicators that may be better surrogates for viral pathogens than fecal indicator bacteria (FIB). This report offers a summary of the existing literature concerning the utility of bacteriophage as indicators of viral presence (fecal sources and surface waters) and persistence (in built infrastructure and aquatic environments). Our findings indicate that bacteriophage levels in all matrices examined are consistently lower than FIB, but similar to viral pathogens. Furthermore, in built infrastructure (e.g. wastewater treatment systems) bacteriophage closely mimic viral pathogen persistence suggesting they may be adequate sentinels of enteric virus removal. AbstractBacteriophages are an attractive alternative to faecal indicator bacteria (FIB), particularly as surrogates of enteric virus fate and transport, due to their closer morphological and biological properties. Based on a review of published data, we summarize densities of coliphages (F+ and somatic), Bacteroides spp. and enterococci bacteriophages (phages) in individual human waste, raw wastewater, ambient fresh and marine waters and removal through wastewater treatment processes utilizing traditional treatments. We also provide comparisons with FIB and enteric viruses whenever possible. Lastly, we examine fate and transport characteristics in the aquatic environment and provide an overview of the environmental factors affecting their survival. In summary, concentrations of bacteriophages in various sources were consistently lower than FIB, but more reflective of infectious enteric virus levels. Overall, our investigation indicates that bacteriophages may be adequate viral surrogates, especially in built systems, such as wastewater treatment plants.

Evaluating the fate of bacterial indicators, viral indicators, and viruses in water resource recovery facilities

“…The total log reductions in enteric viruses over the entire course of the treatment process were more similar to the 2–3 log reduction seen for infectious coliphage indicators than the 3–4 log reduction seen for cultured fecal indicator bacteria, similar to findings described in Dias, Ebdon, and Taylor (), McMinn, Ashbolt, et al. (), Hata et al. (), and Rose et al.…”

“…McMinn, Ashbolt, et al. () compared multiple WRRF studies and concluded that overall fecal indicator bacteria reductions (mean reductions were 2.38 ± 1.26 and 2.22 ± 1.61 for E. coli and enterococci, respectively) were greater than coliphages reductions (mean reductions were 1.46 ± 1.18 and 1.46 ± 1.24 for male‐specific and somatic coliphages, respectively). Pouillot et al.…”

Detection and occurrence of indicator organisms and pathogens

“…The relationships between coliphages and human viruses as well as its relationship to health risk were assessed in several ANNUAL LITERATURE REVIEW studies with inconsistent results. Some researchers (Jofre et al, 2016) considered coliphages correlated with human viruses and health risk, while others (McMinn, Ashbolt, & Korajkic, 2017) declined the statement. McMinn et al (2017) considered Enterococci phages as potential fecal indicators, surviving in both fresh and marine water in tropical and subtropical regions.…”

Pathogens, faecal indicators and human-specific microbial source-tracking markers in sewage

“…; McMinn et al . ) have been extensively studied for this purpose. Humans and animals excrete both groups.…”