Proposed Modifications of Environmental Protection Agency Method 1601 for Detection of Coliphages in Drinking Water, with Same-Day Fluorescence-Based Detection and Evaluation by the Performance-Based Measurement System and Alternative Test Protocol Validation Approaches

Abstract

Coliphages are microbial indicators specified in the Ground Water Rule that can be used to monitor for potential fecal contamination of drinking water. The Total Coliform Rule specifies coliform and Escherichia coli indicators for municipal water quality testing; thus, coliphage indicator use is less common and advances in detection methodology are less frequent. Coliphages are viral structures and, compared to bacterial indicators, are more resistant to disinfection and diffuse further distances from pollution sources. Therefore, coliphage presence may serve as a better predictor of groundwater quality. This study describes Fast Phage, a 16-to 24-h presence/absence modification of U.S. Environmental Protection Agency (EPA) Method 1601 for detection of coliphages in 100 ml water. The objective of the study is to demonstrate that the somatic and male-specific coliphage modifications provide results equivalent to those of Method 1601. Five laboratories compared the modifications, featuring same-day fluorescencebased prediction, to Method 1601 by using the performance-based measurement system (PBMS) criterion. This requires a minimum 50% positive response in 10 replicates of 100-ml water samples at coliphage contamination levels of 1.3 to 1.5 PFU/100 ml. The laboratories showed that Fast Phage meets PBMS criteria with 83.5 to 92.1% correlation of the same-day rapid fluorescence-based prediction with the next-day result. Somatic coliphage PBMS data are compared to manufacturer development data that followed the EPA alternative test protocol (ATP) validation approach. Statistical analysis of the data sets indicates that PBMS utilizes fewer samples than does the ATP approach but with similar conclusions. Results support testing the coliphage modifications by using an EPA-approved national PBMS approach with collaboratively shared samples.

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

“…Recently, some fast and friendly methods that can be adapted to ready‐to‐use kits have become available (Salter et al . ; Muniesa et al . ).…”

Coliphages as Model Organisms in the Characterization and Management of Water Resources

“…Later, a method based on the detection of somatic coliphages through a bioluminescence assay that measured the phage-mediated release of adenylate kinase and detected adenosine 5'-triphosphate was described [65]. In order to obtain results within a day, these methods were improved and adapted to include the enrichment of multiple tube serial dilutions based on the presence/absence test in the USEPA and ISO standards by Salter and Durbin and Salter et al, respectively [66,67]. Ongoing procedures to generate tailored host strains that can detect phage-induced cell lysis would reduce the time required to obtain results to less than four hours, even at low concentrations of somatic coliphages (Muniesa, personal communication).…”

A fluorescence-based method coupled with Disruptor filtration for rapid detection of F + RNA phages

“…With the optimum concentration of host cells applied, as low as 100 PFU of F + RNA phages present in 10 l of water sample were detected within 5 h. The sensitivity of this method is comparable with that described by Salter et al . (), in which F + RNA phages in the level of 1·2–1·5 PFU per 100 ml could be detected. However, the method in this study is more rapid compared with the same‐day prediction in that study (Salter et al .…”