Published Date: 2006-05-31 00:00:00
Subject: PRO/AH/EDR> E. coli O157, sorbitol fermenting - UK (Scotland, England)
Archive Number: 20060531.1519
E. COLI O157, SORBITOL FERMENTING - UK (SCOTLAND, ENGLAND)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Sat, 27 May 2006
From: Pablo Nart <email@example.com>
Source: BBC News [edited]
A rare strain of _E. coli_ O157 was behind the outbreak of the bug
linked to a nursery in Fife, according to experts. Health Protection
Scotland (HPS) said the strain had been seen in Europe and Australia
but was rare in the UK.
A spokesman said the unusual bacterium was hard to identify and
clinicians were being urged to be vigilant when testing samples. The
strain has been linked to 13 cases in Dunfermline, 4 other single
cases in Scotland and 4 cases in England.
HPS said it was working with its sister agency in England to
determine the possible origin of the bug, a sorbitol-fermenting
strain. HPS consultant Dr John Cowden said clinicians had been urged
to ensure the unusual strain was not missed when dealing with samples
from patients who were suspected of having any kind of E.coli O157.
He said: "This unusual strain reacts differently in the laboratory
from other types of _E. coli_ O157 and this is why we are interested
in finding out more about it. It produces the same symptoms as other
strains and our advice to reduce the possibility of becoming infected
with any type of _E. coli_ remains the same."
It is thought the outbreak in Fife was the result of bacterium
spreading from person to person.
[Sorbitol-positive isolates of _E. coli_ O157 present a significant
problem in screening stools for this pathogen, as the lack of
sorbitol fermenting is usually a prime criterion. As this report
points out, if clinical suspicion exists, potential isolates should
be sent to reference laboratories. Toxin production can be detected
by immunoblot, and O157 antigen can be detected by ELISA. Not only
do these isolates ferment sorbitol, but they also are
tellurite-susceptible (1) and will not be isolated on
cefixime-tellurite Sorbitol-MacConkey agar, a selective medium for
the usual _E. coli_ O157. Lactose-fermenting Salmonella species
represent a similar diagnostic problem (2).
Although first recognized in Germany in 1988 (1),
sorbitol-fermenting, verotoxigenic _E. coli _O157 was thought to be
restricted to continental Europe (3) until an isolation in Australia
in 2002. The first isolation in the UK was reported in 2002 (see: E.
coli O157, sorbitol fermenting - UK (Scotland) 20021101.5685).
1. Karch H, Bielaszewska M. Sorbitol-fermenting shiga toxin-producing
_Escherichia coli_ O157:H- strains: epidemiology, phenotypic and
molecular characteristics, and microbiological diagnosis. J Clin
Microbiol 2001;39: 2043-9.
2. McDonough PL; Shin SJ; Lein DH: Diagnostic and public health
dilemma of lacto fermenting _Salmonella enterica_ serotype
typhimurium in cattle in the northeastern United States. J Clin
Microbiol 2000 Mar;38:1221-6
3. Bettleheim KA, Whipp M, Djordjevic SP, Ramachandran V. First
isolation outside Europe of sorbitol-fermenting verocytotoxigenic
_Escherichia coli_ (VTEC) belonging to O group O157. J Med Microbiol
2002; 51: 713-4. - Mod.LL]