Abstract
1. An outbreak ofSalmonella derby, involving sixty-eight patients, is described.2. The organism was isolated from clinical cases, from carriers and also from dust in the wards, from a mouse and from a hand towel used by nurses.3. The value of tetrathionate broth with subsequent cultivation on ‘SS’ agar as an aid to isolation ofSalmonellabacilli was confirmed.4. Cultural and biochemical characters ofSalm. derbywere recorded.5. The antigenic structure of the isolated strains ofSalm. derbywas demonstrated, showing the presence of factorland the absence of a minor flagellar antigen.6. A serological response toSalm. derbyinfection was shown in patients, their sera containing H antibodies of a titre 1/20 to 1/320, whereas O agglutinins were absent at the time the tests were made.7. Pathogenicity tests were performed on mice indicating the possibility of infectionper osor by intraperitoneal injections. Mice were found to be potential faecal and urinary carriers.