Accession Number : AD0468294


Title :   STUDIES ON THE GENETICS OF VIRULENCE IN ENTERIC BACTERIA.


Descriptive Note : Final technical rept. 1 Sep 64-1 Sep 65,


Corporate Author : GEORGE WASHINGTON UNIV WASHINGTON DC SCHOOL OF MEDICINE


Personal Author(s) : Parlett, Robert C


Report Date : 01 Sep 1965


Pagination or Media Count : 15


Abstract : A Shigella flexneri 2a hybrid produced by mating with an Escherichia coli Hfr strain lost its ability to cause a fatal enteric infection when fed to starved guinea pigs. However, the hybrid retained other properties of virulence associated with its virulent S. flexneri parent, namely, the ability to produce kerato-conjunctivitis in guinea pigs, and the ability to invade and multiply within HeLa cells. Examination of pathology in the starved guinea pig model showed that the parent Shigella strain invaded the intestinal mucosa causing a severe inflammatory reaction in the lamina propria, which progressed to ulceration of the intestine and death of the animal. The hybrid also invaded the intestinal mucosa and produced an inflammatory reaction. However, it failed to maintain itself in the mucosa, the inflammatory reaction subsided, the intestine returned to normal within 4 days and the animal survived. These findings indicate that Shigella virulence involves both the capacity to reach the lamina propria and the ability to multiply in this region. A Salmonella typhosa Hfr strain was used to transfer the Vi antigen and somatic antigen 9 to S. typhimurium recipient strains, and the genetic determinants of these antigens were mapped. (Author)


Descriptors :   GENETICS , BACTERIA , VIABILITY , ANTIGENS , ANTIBODIES , SHIGELLA FLEXNERI , ESCHERICHIA COLI , SALMONELLA TYPHOSA , GUINEA PIGS , GROWTH(PHYSIOLOGY) , TISSUES(BIOLOGY) , CHROMOSOMES


Distribution Statement : APPROVED FOR PUBLIC RELEASE