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Title: ISOLATES OF SALMONELLA ENTERICA ENTERITIDIS PT4 WITH ENHANCED HEAT AND ACIDTOLERANCE ARE MORE VIRULENT IN MICE AND MORE INVASIVE IN CHICKENS

Author
item HUMPHREY, T. - PHLS FOOD MICRO.RES.UNIT
item WILLIAMS, A. - CENTRE FOR APP.MICRO.RES
item MCALPINE, K. - PHLS FOOD MICRO.RES.UNIT
item LEVER, M. - CENTRE FOR APP.MICRO.RES.
item PETTER, JEAN
item COX, J. - UNIV. OF NEW S. WALES

Submitted to: Epidemiology and Infection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: This manuscript describes how Salmonella enteritidis phage type (pt) 4 isolates vary in their ability to cause disease in chicks, egg-laying hens and mice. A strain that was more virulent was also more resistant to the effects of heat and acid. This is an important finding since it indicates that virulent strains of Salmonella enteritidis might be more likely to survive cooking or food processing techniques that use acidification to retard microbial growth. An important aspect of this manuscript is that it confirmed findings made by a USDA scientist that more virulent strains of Salmonella enteritidis, regardless of phage type, could be identified by their colony morphology on plates. In 1993 this information was shared with researchers in England, who were working on phage type 4 strain heat and acid tolerance at that time. The collaboration that developed involved scientists from England, Australia, and America. Thus there is an emerging consensus that some strains of Salmonella enteritidis are particularly adapted to withstand deleterious environmental conditions.

Technical Abstract: Two Salmonella enteritidis PT4 isolates which differed in inherent tolerance to heat, acid, hydrogen peroxide and the ability to survive on surfaces were used to infect mice, day-old chicks or laying hens. The acid-, heat-, hydrogen peroxide- and surface-tolerant isolate was more virulent in mice and more invasive in laying hens, particularly in reproductive tissue. However, no significant differences were observed i behavior in chicks. Both PT4 isolates were able to infect chicks housed in the same room as infected birds, although the heat-tolerant isolate survived significantly better than the heat-sensitive one in aerosols.