Cl. Roberts et al., THE ROLE OF HEIGHTENED SURVEILLANCE IN AN OUTBREAK OF ESCHERICHIA-COLI O157.H7, Epidemiology and infection, 115(3), 1995, pp. 447-454
After instituting laboratory screening for Escherichia coli O157.H7, a
Connecticut hospital isolated the organism from four persons in Septe
mber 1993. As a result, an outbreak of E. coli O157.H7 associated with
a country club was detected. The club had served hamburger from the s
ame shipment at two picnics. Attendees of two picnics were interviewed
, stool cultures mere obtained from symptomatic persons, and the remai
ning hamburger was cultured. Twenty (22%) of 89 persons who ate hambur
ger became ill; compared with 1 of 60 who did not eat hamburger (relat
ive risk = 13.5, 95% confidence interval 3.2-56.3). Among persons who
ate hamburgers, illness was strongly associated with eating hamburger
that was not thoroughly cooked (P < 0.001). All 20 samples from 5 rema
ining boxes of patties yielded E. coli O157.H7. Isolates from hamburge
r and case-patients mere indistinguishable by pulsed-field gel electro
phoresis. Heightened surveillance can rapidly identify outbreaks and m
ay mitigate their impact. However, continued review of food safety iss
ues is necessary if E. coli O157.H7 outbreaks are to be prevented.