PRODUCTION OF Vi ANTIGEN ON A CHEMICALLY DEFINED MEDIUM BY A COLIFORM BACTERIUM

Abstract
The nutritional requirements of Escherichia (or Citrobacter) freundii strain 5396/38 for growth and Vi antigen production were examined. The organism requires calcium pantothenate for optimal growth and glutamate for optimal Vi antigen production. The distribution of antigen between cells and medium varies with growth time, a greater proportion of antigen being found dissolved in the medium in older cultures. Evidence for critical unknown mineral requirements for optimal antigen production is reported.