THE GROWTH OF NEISSERIA MENINGITIDIS IN SIMPLE CHEMICALLY DEFINED MEDIA

Abstract

The growth of 4 widely different strains of N. meningitidis on a simple medium was investigated. The liquid medium used contained only glutamic acid, cystine, mineral salts and required incubation in an increased CO2 atmosphere. Following the concept that "training" a strain to grow on a simple medium is really selecting suitable variants which are normally present in the parent strain, each strain was grown for 1 or 2 passages in the simple medium. Using the original cultures, growth occurred promptly if the inocula was sufficiently large[long dash]107 to 108 organisms. After the period of training, growth could be initiated with much smaller inocula[long dash]10 to 1000 organisms. The proportion of suitable variants in the parent strain appeared to vary in the different strains. The simple medium descr. is not optimal for growth from small inocula, but there is some evidence that it might become so if supplemented with a mixture of amino acids.