TYPING OF SALMONELLA-ENTERICA SEROVAR SAINTPAUL - AN OUTBREAK INVESTIGATION

During the summer of 1993 an outbreak of human salmonellosis caused by Salmonella serovar Saintpaul occurred in Denmark. A total of 35 isola tes originating from pigs, turkeys and imported foodstuffs, and 10 hum an isolates were compared following their characterization by agglutin ation of the O:5 factor, antibiogram typing, plasmid profiling, riboty ping and pulsed field gel electrophoresis, in order to identify the mo st probable source of infection. After typing, the source of the inves tigated outbreak remains obscure because so far no isolates with trait s of the outbreak strain have been recovered from production animals. Presence of the O:5 factor and absence of plasmids in human and porcin e isolates pointed to pork as the source of infection, whereas human i solates and all Danish isolates from turkeys had the same ribotype, in dicating that turkey was the infection source. A possible explanation for the failure to find isolates with traits of the outbreak strain co uld be the presence of a third, but so far unidentified, source. The p resent investigation illustrates the necessity of using more than one epidemiological typing method for outbreak investigation. This is espe cially important when the organism involved is relatively uncommon and little is known about its diversity and distribution.