Motility in the Examination for B. Typhosus and Related Pathogens

Abstract

Bacteriologic diagnosis of typhoid fever and related infections has centered about the utilization of biochemical differences between the pathogenic organisms concerned and the non-pathogenic forms associated with them. The usual initial procedure in the examination of a suspected typhoid stool is seeding upon some lactose plating medium to eliminate all but the non-fermenting organisms present. The principal reasons to explain the failure to isolate the typhoid bacillus are: scarcity of B. typhosus in the stool, or the overwhelming antagonistic action of the associated bacteria. Glycerin, bile, and selectively bacteriostatic substances such as brilliant-green have been incorporated into the stool fluid or into the media. The object is either to forestall the destruction of whatever typhoid bacilli may be present or to hinder the growth of the non-pathogenic organisms of the mixture without inhibiting B. typhosus.Given a mixture in which the desired bacteria were present in very small numbers, it would se...