THE PRODUCTION AND PROPERTIES OF SALMONELLA TYPHI SPHEROPLASTS

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Abstract
S. typhi spheroplasts were produced by growing typhoid organisms in a liquid semisynthetic medium containing 1.5 to 2.0% glycine. The addition of traces of magnesium and glucose concentrations of 0.5 to 2.0% was required for optimal growth conditions. These cells were considered to be of the transition L form since they reproduced as spheroplasts as long as they were grown in the glycine medium, but unlike a true L organism they reverted to the normal bacillary form when subcultured to glycine-free medium.The lytic susceptibility of S. typhi spheroplasts was studied. They were found to be resistant to a number of detergents, alcohols, and enzymes. They could, however, be broken up by osmotic shock and were lysed by trypsin, pancreatic lipase, and, best of all, by Dornavac(R), a commercial preparation of pancreatic desoxyribonuclease which, in addition, contains traces of other enzymes, such as trypsin and lipase. Studies towards the production of an enzyme-lysed sphero-plast vaccine for the prevention of typhoid are now in progress.