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Infect Immun, April 1998, p. 1467-1472, Vol. 66, No. 4
Molecular Microbiology Unit, Women's and
Children's Hospital, North Adelaide, South Australia,
5006,1 and
Microbial Pathogenesis Unit,
Department of Microbiology and Immunology, University of
Adelaide, Adelaide, South Australia, 5005,2
Australia
Received 4 December 1997/Accepted 14 January 1998
Western blot analysis was used to assess the reactivity of
convalescent-phase sera from patients who were associated with an
outbreak of hemolytic-uremic syndrome (HUS) caused by fermented sausage
contaminated with Shiga toxin-producing Escherichia coli (STEC). The predominant STEC isolated from HUS patients belonged to
serotype O111:H
0019-9567/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Molecular Analysis of Shiga Toxigenic
Escherichia coli O111:H
Proteins Which React
with Sera from Patients with Hemolytic-Uremic Syndrome
, and reactivity to O111:H
whole-cell lysates, treated or untreated with proteinase K, was examined. As expected, all five serum samples demonstrated a marked anti-lipopolysaccharide response, but several protein bands were also
immunoreactive, particularly one with an apparent size of 94 kDa. One
convalescent-phase serum sample was subsequently used to screen an
O111:H
cosmid bank and 2 of 900 cosmid clones were found
to be positive, both of which contained a similar DNA insert. Western
blot analysis of one of these clones identified three major
immunoreactive protein bands of approximately 94, 70, and 50 kDa. An
immune response to the three proteins was detectable with all five
convalescent-phase serum samples but not with healthy human serum.
Immunoreactive 94- and 50-kDa species were produced by a deletion
derivative of the cosmid containing a 7-kb STEC DNA insert. Sequence
analysis of this region indicated that it is part of the locus for
enterocyte effacement, including the eaeA gene which
encodes intimin. The deduced amino acid sequence of the
O111:H
intimin was 88.6% identical to intimin from
O157:H7 STEC, and the most divergent region was the 200 residues at the
carboxyl terminus, which were only 75% identical. Such variation may
be antigenically significant as serum from a HUS patient infected only
with the O111:H
STEC reacted with intimin from an
enteropathogenic E. coli O111 strain, as well as several
other eaeA-positive STEC isolates, but not with an
eaeA-positive STEC belonging to serotype
O157:H
. Sera from two of the other HUS patients also
failed to react with intimin from this latter strain. However, intimin
from O157:H
STEC did react with serum from a patient
infected with both O111:H
and O157:H
STEC.
*
Corresponding author. Mailing address: Molecular
Microbiology Unit, Women's and Children's Hospital, North Adelaide,
S.A., 5006, Australia. Phone: 61-8-8204 6302. Fax: 61-8-8204 6051. E-mail: patonj{at}wch.sa.gov.au.
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