Elucidation of Probable Mechansm for Biocidal Resistane in Skin-borne Bacillus subtilis

Abstract

An attempt has been made in the present investigation to determine the probable mechanism through which a skin-borne bacterium Bacillus subtilis might develop resistance against a dithiocarbamate based biocide. Changes occurring in the cell wall constituents and morphology in the cells grown at sub-optimal level concentrations of biocide were studied based on which the probable mechanism of buildup of biocidal resistance has been proposed. There has been considerable change/reduction in cell wall constituents, peptidoglycan, diaminopimelic acid and teichoic acid due to the presence of biocides. By propidium iodide staining technique, the cell wall permeability has also been found to be reduced. The morphology of the cells as studied using scanning electron microscopy reveals that there is a shortening of rod shape of the cells due to the action of the biocide. Based on the results of the study, it is proposed that the skin-borne Bacillus subtilis encountered in leather processing might develop resistance through changes in the cell wall constituents and reduction in the cell wall permeability.