Comparison of two filtration-elution procedures to improve the standard methods ISO 10705-1 & 2 for bacteriophage detection in groundwater, surface water and finished water samples.

摘要

Aim: To select a reliable method for bacteriophage concentration prior detection by culture from surface water, groundwater and drinking water to enhance the sensitivity of the standard methods ISO 10705-1 & 2. Methods and Results: Artificially contaminated (groundwater and drinking water) and naturally contaminated (surface water) 1-litre samples were processed for bacteriophages detection. The spiked samples were inoculated with about 150 PFU of F-specific RNA bacteriophages and somatic coliphages using wastewater. Bacteriophage detection in the water samples was achieved using the standard method without and with a concentration step (electropositive Anodisc membrane or a pretreated electronegative Micro Filtration membrane, MF). For artificially contaminated matrices (drinking and ground waters), recovery rates using the concentration step were superior to 70% whilst analyses without concentration step mainly led to false negative results. Besides, the MF membrane presented higher performances compared with the Anodisc membrane. Conclusion: The concentration of a large volume of water (up to one litre) on a filter membrane avoids false negative results obtained by direct analysis as it allows detecting low number of bacteriophages in water samples. Significance and Impact of the Study: The addition of concentration step before applying the standard method could be useful to enhance the reliability of bacteriophages monitoring in water samples as bio-indicators to highlight faecal pollution