Methodology for detection, enumeration, propagation and manipulation of bacteriophages

Abstract

A method to propagate, enumerate and quantify bacteriophage(s) in a water sample or other aqueous sample was designed which contains ingredients to stimulate the growth of select bacterial species which are susceptible to infection by specific bacteriophage(s), in which interfering background organisms are either inhibited or inconsequential. Important features of the medium include oxidation-reduction compounds producing colored and/or fluorescent products, chromogenic and/or fluorogenic enzyme substrates, and temperature-independent gelling agent(s). A preferred combination is the growth medium containing 2,3,5-triphenyl tetrazolium chloride, 5-bromo-4-chloro-3-indolyl-B-D-galactoside, and appropriate gelling agents, which (when properly used) produces a dark red bacterial lawn containing teal blue-green, irregularly circular spots representing individual phage plaque, all discernible to the eye in visible light. The procedure can also be readily applied towards automatic counting systems under artificial illumination. The procedure can be employed with water samples and with elution buffers that can retain bacteriophages in suspension following contact by the buffer with foods, soils, hard surfaces and other solids that may be contaminated by bacteriophages.