Quantitative Distribution of Infectious F-Specific RNA Phage Genotypes in Surface Waters

Abstract

F-specific RNA phages (FRNAPHs) are considered potential viral indicators of water pollution due to their occurrence and stability in water environments. However, their suitability as viral indicators is not fully elucidated because the characteristics of FRNAPHs are variable depending on the genotype. In this study, for the characterization of infectious FRNAPH genotypes, integrated culture reverse transcription-PCR coupled with the most probable number approach was applied to surface water samples. Further, to recover low concentrations of FRNAPH genotypes, an FRNAPH recovery method was developed. The novel FRNAPH recovery method using a noncharged microfiltration membrane could effectively recover FRNAPH strains without inactivation, while a method using an electronegative microfiltration membrane resulted in the inactivation of some strains. Infectious FRNAPH genotypes in surface water samples were successfully quantified with an efficiency comparable to that of the conventional plaque assay. Genotype I (GI) and GII FRNAPHs tended to be predominant at locations impacted by treated and untreated municipal wastewater, respectively. The numbers and proportions of infectious FRNAPHs tended to be higher during the winter season when water temperature decreased. IMPORTANCE Properties of FRNAPHs are highly variable depending on their genotypes. Previous typing methods for

In Situ Dynamics of F-Specific RNA Bacteriophages in a Small River: New Way to Assess Viral Propagation in Water Quality Studies

“…Therefore, in addition to the propagation of infectious FRNAPHs in surface water by advection processes, results reveal a natural inactivation of bacteriophages related to water temperature. The impact of the seasonal temperature (summer vs winter) on the survival of infectious FRNAPHs was previously shown (Durán et al 2002 ; Hata et al 2016 ). In order to characterize the in situ survival of the distinct genogroups of infectious FRNAPHs, genotyping of 287 individual infectious phage plaques was carried out.…”

Viral indicators for tracking domestic wastewater contamination in the aquatic environment

“…Therefore, to identify and quantify specific FRNAP genogroups, it is necessary to use genogroup-specific molecular detection methods. Such methods include RT-PCR analysis of plaques (Haramoto et al, 2015(Haramoto et al, , 2012) and 1-day ICC-RTqPCR (Hartard et al, 2017), most-probable number assays (Hata et al, 2016) or insitu plaque membrane hybridisation techniques (Flannery et al, 2013).…”

“…FRNAP are easily cultured, and their persistence in surface waters has been studied in both surface freshwaters and seawater (Hata et al, 2016;Muniesa et al, 2009;Ravva and Sarreal, 2016;Yang and Griffiths, 2013). In general, FRNAP-I has been found to be the most persistent followed by FRNAP-II, FRNAP-III and then FRNAP-IV.…”

Metagenomic Analysis of Infectious F-Specific RNA Bacteriophage Strains in Wastewater Treatment and Disinfection Processes

“…IC-RT-PCR-MPN was performed to quantify the infectious FRNAPH genotypes as previously described [6,34,35]. Infectious FRNAPH genotypes in the samples were primarily propagated overnight at 37 • C by mixing with an equal volume of tryptone-glucose broth containing S. enterica WG49 (described above).…”

“…Conversely, culture combined with PCR (integrated culture-PCR (IC-PCR)) can detect infectious viruses. For example, IC-RT-PCR combined with a most probable number (MPN) assay (IC-RT-PCR-MPN) has been used to quantitatively detect infectious FRNAPH genotypes [6,34,35]. Thus, we hypothesized that the application of NGS for detecting of FRNAPH strains propagated in a liquid medium may be effective for detecting infectious FRNAPH strains.…”