Evaluation of 1MDS electropositive microfilters for simultaneous recovery of multiple microbe classes from tap water

The 1MDS electropositive microfilter was designed specifically for virus capture and recovery from water, but its electrostatic properties raise the possibility that 1MDS filters can also effectively capture bacteria and parasites present in water samples. This filter is recommended by United States Environmental Protection Agency (USEPA) for recovering human enteric viruses from water matrices through the Virus Adsorption-Elution (VIRADEL) technique. If bacteria and parasites can also be concentrated and recovered using 1MDS filters, this sampling technique would have greater utility and cost-effectiveness for microbial water quality testing. In this study, both 142-mm flat and 25.4-cm cartridge 1MDS filters (Cuno) were tested to determine their effectiveness for recovery of MS2 and phi X174 bacteriophage, Salmonella enterica (serovar Typhimurium), Bacillus globigii endospores, and Cryptosporidium parvum oocysts from a tap water matrix. By amending the USEPA standard beef extract/glycine eluent with a surfactant (Tween 80) and dispersant (sodium polyphosphate) and varying the pH and temperature, multiple eluent conditions were compared in order to identify an optimum eluent for all organisms. While viruses, bacteria, and parasites are effectively retained by the 1MDS filter, elution efficiencies and associated recovery efficiencies varied for each organism.