Epidemiology and Infection

Research Article

A comparison of Salmonella enteritidis phage types from egg-associated outbreaks and implicated laying flocks

S. Altekrusea1 c1, J. Koehlera2, F. Hickman-Brennera2, R. V. Tauxea2 and K. Ferrisa3

a1 The Food and Drug Administration, Washington. DC

a2 Centers for Disease Control. Atlanta. GA

a3 United States Department of Agriculture, Ames, Iowa


Infections due to Salmonella enteritidis are increasing worldwide. In the United States, between 1985 and 1989. 78% of the S. enteritidis outbreaks in which a food vehicle was identified implicated a food containing raw or lightly cooked shell eggs.

Under a US Department of Agriculture regulation published in 1990, eggs implicated in human food-borne S. enteritidis outbreaks were traced back to the source flock. The flock environment and the internal organs of a sample of hens were tested for S. enteritidis. We compared the S. enteritidis phage types of isolates from 18 human, egg-associated outbreaks and the 15 flocks implicated through traceback of these outbreaks. The predominant human outbreak phage type was recovered from the environment in 100% of implicated flocks and from the internal organs of hens in 88% of implicated flocks we tested. The results support the use of phage typing as a tool to identify flocks involved in human S. enteritidis outbreaks.

(Accepted August 24 1992)


c1 Sean F. Altekruse. Food and Drug Administration. Center for Food Safety and Applied Nutrition. HFF-265. 200 C Street. S.W.. Washington. DC 20204.