Published Date: 2006-06-01 00:00:00
Subject: PRO/AH/EDR> E. coli O157, sorbitol fermenting - UK (Scotland, England)
Archive Number: 20060601.1529
E. COLI O157, SORBITOL FERMENTING - UK (SCOTLAND, ENGLAND)(02)
A ProMED-mail post
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International Society for Infectious Diseases
Date: Thu, 1 Jun 2006
Source: Eurosurveillance [edited]
[This report from Eurosurveillance also includes some separate cases
in Scotland that have not been shown to be sorbitol-fermenting. -
At least 3 separate outbreaks of _E. coli_ O157 infections have
recently been occurring in Scotland and England (1, 2, 3). 2
outbreaks have occurred in different areas of Scotland, and 4 cases
have been reported in northeast England. Health authorities in
Scotland and England are working together to investigate whether any
common factors exist that might link the cases.
An outbreak of _E. coli_ O157 infections linked to a nursery in Fife
(in the east of Scotland) was detected in May 2006, and by 29 May, 13
cases had been confirmed (4). 7 of the 13 isolates detected were in
asymptomatic carriers, and were discovered as a result of screening
contacts. 4 infected children were admitted to hospital with
hemolytic uraemic syndrome (HUS), and all have now been discharged.
In addition to the confirmed cases, 10 possible cases have been
identified as a result of ongoing investigations in patients who had
symptoms and a link to the nursery, and results from stool tests are
The Scottish _E. coli_ O157 Reference Laboratory has confirmed that
the outbreak strain is a sorbitol-fermenting strain of _E. coli_
O157. Clinicians have been urged to be alert to further occurrences.
A 2nd Scottish outbreak of _E. coli_ O157 infections, which is not
thought to be connected to the Fife outbreak, has occurred in a
village in Lanarkshire (central Scotland) (5). Three confirmed cases
have been reported since 24 May 2006. All 3 cases are linked to a
butcher's shop in the village, and the 3 patients are recovering. A
further suspected case that is not linked to the 3 confirmed cases
has also been identified in Lanarkshire and the patient is stable in
No conclusive evidence has been found to show that the butcher's shop
is the source of the outbreak, but as a precautionary measure the
owner has voluntarily closed the shop temporarily, and local health
authorities have advised the public to dispose of any food that was
bought from the shop other than raw meat. Another butcher's shop in
the area was supplied with cooked meat from the first shop, and the
public has been advised to dispose of this product too. Hygiene
recommendations including advice on handwashing and safe storage of
food have been given to the public to reduce the risk of infection,
and a telephone helpline is available.
Details of the strain(s) causing these cases in Lanarkshire are not
Atypical verocytotoxin-producing _E. coli_ (VTEC) O157 that ferments
D-sorbitol has been reported in isolates from 4 patients in England
(3). One of the patients was a child in Yorkshire and the Humber
(northeast England) who had been admitted to hospital with HUS, and
subsequently died. The other 3 isolates were detected as a result of
investigation of HUS cases in another part of the region. Phage
typing showed that the isolates reacted identically with the typing
phages to give a pattern that did not conform to a designated type
(RDNC). All isolates possessed genes for verocytotoxin (VT) 2, and
pulsed field gel electrophoresis of DNA fragments gave
Enhanced ascertainment of sorbitol fermenting VTEC O157:
Sorbitol-fermenting VTEC O157 was first recognized in 1988 in Germany
during an outbreak of HUS (6) and has caused infections in
continental Europe and Australia. Previous reports of infections with
sorbitol-fermenting VTEC O157 comprised single cases in Scotland in
2002 and 2003 (7) and one case in England in 2004. It is possible,
however, that there is under-ascertainment of this pathogen because
of testing methods.
Standard protocols for the isolation of presumptive VTEC O157 from
feces target the more common sorbitol non-fermenting strains and use
sorbitol-Macconkey (SMAC) agar containing cefixime and tellurite
(CT-SMAC) as a selective medium. Sorbitol-fermenting VTEC O157 grow
as pink colonies on SMAC agar and some may grow relatively poorly on
CT-SMAC, although this property appears variable.
Revised guidance has been issued to laboratories and specialists in
England and Wales on the testing of clinical samples for
sorbitol-fermenting VTEC O157. If clinical symptoms are suggestive of
VTEC infection (particularly in children aged under 15 years and
adults aged over 65 years), and presumptive sorbitol non-fermenting
_E. coli_ O157 colonies are not observed on SMAC or CT-MAC agar, then
sorbitol-fermenting colonies should be tested for agglutination with
_E. coli_ O157 antiserum. Colonies giving agglutination should be
identified as _E. coli_ and sent to the Laboratory of Enteric
Pathogens in London for confirmation, phage typing, and detection of
VT genes. Fecal samples from appropriate clinical cases from whom
VTEC O157 has not been isolated may be submitted for detection of
non-O157 VTEC. 3 of the 4 cases in England from which
sorbitol-fermenting VTEC O157 was isolated also possessed serum
antibodies to O157 lipopolysaccharide.
This article is adapted from references 1-3.
[Authors: Editorial team (<firstname.lastname@example.org>),
Eurosurveillance editorial office]
1. E.coli O157 outbreak, Fife - update. HPS Weekly Report 2006; 40(21); 117.
2. E.coli O157 outbreak, - Lanarkshire. HPS Weekly Report 2006; 40(21); 117.
3. Health Protection Agency. Sorbitol-fermenting
Verocytotoxin-producing E. coli O157 (VTEC O157). CDR Weekly 2006;
4. Updated statement on E. coli O157 outbreak from NHS Fife 29 May
2006. NHS Fife, press release 29 May 2006.
5. E. coli outbreak - update. NHS Lanarkshire, press release 30 May 2006.
6. Karch H, Bohm H, Schmidt H, et al: Clonal structure and
pathogenicity of Shiga-like toxin-producing, sorbitol-fermenting
Escherichia coli O157:H-. J Clin Microbiol 1993; 31: 1200-5.
7. Allison L: HUS due to a sorbitol-fermenting VTEC O157 in Scotland-
October 2003. Eurosurveillance Weekly 2002; 6(4): 021031.