Lynch, Darrel L.
M.S. (Master of Science)
Department of Biological Sciences
Escherichia coli; Antibacterial agents
Strains of E. coli found in nature are sensitive to the bacteriostatic effect of irgasan at concentrations of 1-3 ppm. E. coli LMR-26 was shown to be resistant in media amended with 35 ppm irgasan. This strain required the presence of a divalent cation (Mg⁺⁺ or Ca⁺⁺) in the medium to manifest such resistance to irgasan. Resistance to a similar concentration of hexachlor- ophene with one of the above divalent cations present was also observed with E. coli LMR-26. Comparative analysis of total envelope proteins using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed no significant difference between an irgasan- sensitive wild strain and the resistant organism. Gas liquid chromatography (GLC) did however resolve significant differences in the envelope fatty acids of the two test organisms. Use of the transmission electron microscope has revealed major morphological modifications in the resistant organism subjected to an irgasan stress. A possible mechanism of resistance is discussed.
Persino, Richard L., "Divalent cation dependent resistance in E. Coli LMR-26 to the broad spectrum antimicrobial agent Irgasan" (1981). Graduate Research Theses & Dissertations. 2270.
Northern Illinois University
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