Detection of F⁺ bacteriophage in large volumes of water by a membrane filter method (MFM)

In recent years, F⁺ bacteriophages were proposed by several researchers as an alternative to fecal coliforms to signal the presence of fecal pollution in water sources. The sample volume which can be monitored for the presence of bacteriophages by the conventional methods is limited to 1-10 ml. This study was conducted to test the feasibility of detecting and enumerating F⁺bacteriophages in large volumes of water by an MFM. A recovery of up to 100% was observed for MS2 coliphage when the pH of the water samples was adjusted to 3.5. The presence of humic acid in the water interfered with the adsorption of phages to the membrane filter. F⁺bacteriophages were detected in 11 out of 50(22%) water samples collected from swimming pools in Jerusalem. Total coliform were detected in only 2 out of the 50 (4%) samples. Both indicator microorganisms were detected in only one sample, suggesting the lack of correlation between their presence. The results of this study demonstrated that the MFM is a sensitive assay for detecting low concentrations of F⁺bacteriophages in large volumes of water.