Abstract
The in vitro intracellular growth of various species of salmonellae tested by the roller tube technique. using rabbit peritoneal macrophages was compared with their pathogenicity which was examined by intravenous and intraperitoneal inoculations into rabbits. Strains of S. choleraesuis, S. enteritidis, S. typhimurium and S. paratyphi B showed apparent intracellular growth, while no growth could be observed with S. paratyphi A, S. typhosa and Escherichia coli (0-55). Among the former strains, S. paratyphi B showed a particular microscopic finding in which no marked degeneration or destruction of cells occured in spite of the rapid multiplication of organisms. When each one strain of the 4 species which multiplied intracellularly was inoculated into rabbits, only S. choleraesuis elicited typical typhoid infection with high fever and bacteremia, while the others showed only a slight pathogenicity with temporary fever and antibody formation. The granuloma formation in the liver was noted in rabbits inoculated with the 4 species. No sign of infection and pathological change could be found in rabbits inoculated with S. paratyphi A.
