The Significance of the Large Bodies and the Development of L Type of Colonies in Bacterial Cultures

Abstract

By examination of a large num-ber of routine bacteriological cultures a few strains which produced large bodies in abundance were observed in many species. In all spp., including Streptobacillus monili-jormis, the morphological appearance of the large bodies was similar, and they were produced by gradual swelling of the bacteria. In cultures of Hemophilus influenzae, Escherichia coli and Streptobadllus moniliformis the germination of the large bodies was observed. Their descendants are different from the parent organism and are similar both in morphology and development to the pleuro-pneumonia group of organisms. Such "L type" of colonies were observed in cultures of a Flavobacterium, of Bacillus fundiliformis and of the gonococcus in addition to the 3 spp. already mentioned. They were isolated in pure cultures from B. junduliformis and from the Flavobacterium. Strains which produced L type of colonies are rare in most species. They are in a transient stage of increased variability. A strain of Flavobacterium, and 2 strains of colon bacilli presenting these phenomena have been described in detail. The significance of these observations depends mainly on whether the L type of colonies are genetically connected with the bacteria. The cultures of Streptobacillus moniliformis were further studied in connection with this question. The author''s previously expressed conclusion that the L type of growth is a variant of the bacteria has remained unchanged.