A Simplified Medium for Pathogenic Organisms

Abstract

A medium is described with 40-60 ml tomato juice added to the following: peptone (Difco), 5 g.; NaCl, 5 g.; Na2HPO4 12H2O, 2.5 g.; KH2PO4, 0.35 g.; MgCl2 6H2O, 0.3 g.; H2O, 1000 ml. The tomato juice is obtained by pressing fresh tomatoes and neutralizing to pH 7 just before adding aseptically to the peptone-salts soln. This basic standard medium appears to have many advantages over the one at present in use in most bacteriological laboratories: it is simpler and more easily prepd., with considerable saving in time and materials; it supports growth of all common pathogenic bacteria as well as many of those having special requirements, such as the streptococci, pneumococci, diphtheria bacilli and lactobacilli. The Neisseriae do not grow on this medium without the addition of blood. The medium can be used as a base for the common differential media.