A Comparison of the Molecular Filtration Technique with Agar Plate Counting for Enumeration of Escherichia coli in Various Aqueous Concentrations of Zinc and Copper Sulfates1

The Inhibition of Spores of Bacillus subtilis by Cetrimide Retained on Washed Membrane Filters and on the Washed Spores

“…MEMBRANE FILTERS have been employed in a variety of bacteriological techniques including viable counting (Clark, Geldreich, Jeter & Kabler, 1951), sterility testing (Holdowsky, 1957) and the investigation of bactericidal activity (Shipe & Fields, 1954; Harris & Richards, 1958; Hess & Speiser, 1 9 5 9~~6 ) .…”

Evidence for Environmental Factors, Including Presence of Heavy Metals, Involved in Converting Potential Pathogens to a Viable But Nonculturable State in River and Estuarine Water

“…The toxic effect of copper and, to a lesser extent, zinc on Escherichia coli suspended in double distilled water was reported thirty-six years ago. 5 More recently, Domek, et al 6 , described sublethal injury or loss of viability of coliform bacteria caused by copper in drinking water in concentrations as low as 25 ug/Ml. Wells studied the effect of various piping materla!-: on bacterial viability and showed that a strain of Aeromonas spp.…”

Use of Molecular Filter Membranes for Water Potability Control

“…These discrepancies may be caused by specific characteristics of microorganisms in the sample, inhibitory action of growth medium, or peculiarities of the water examined. Shipe and Fields (7) have shown that excessive concentrations of copper and zinc salts in water may cause MF coliform organism results to be considerably lower than agar plate counts. It is possible that other materials may interfere.…”