THE PROPERTIES OF L FORMS ISOLATED FROM SALMONELLA AND THE ISOLATION OF L FORMS FROM SHIGELLA

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Abstract
Under appropriate conditions all freshly isolated Salmonella strains produced L-type colonies. S. typhosa and some strains of S. typhimurium produced only one type of colony that corresponds to the L1 of Streptobacillus moniliformis and the 3A L-type colonies of Proteus. The bacilli were not regained from these colonies. Other strains of Salmonella typhimurium and one of S. enteritidis produced 3B L-type colonies in addition. These colonies could be propagated only in pour plates containing penicillin. In the absence of penicillin the bacilli returned from the 3B L-type cultures within a few hrs. The macroscopical appearance of the 3A L-type cultures of Salmonel-la when adapted to the media and growing abundantly is markedly different from the L1 isolated from Streptobacillus moniliformis and the L-type cultures of Proteus. However, the structure of the colonies and the morphology of the organisms are similar in all L-type cultures. The serol. properties and the sugar fermentation reactions were found to be similar to those of the parent bacilli. It is apparent in Salmonella as in Proteus that the L forms and the bacilli are growth forms of the same organism. The nature of the differences between the 2 growth forms and the possible significance of the L forms are unknown. Freshly isolated Shigella paradysenteriae and S. sonnei strains produced L-type colonies on soft horse serum agar containing high concns. of penicillin. The L-type colonies obtained from S. sonnei remained very small and could not be propagated in transplants. A sparse growth was obtained from the L-type colonies of S. paradysenteriae. The bacilli were not regained from the L-type cultures of Shigella.