BRIAN DEER:
MATTHEW AND THE BURGER BUG Page 2
Matthew's
stool test was carried out in the Lancaster
infirmary's microbiology lab, on the third floor of
the pathology building, a few steps from ward 34.
Last year, it processed 70,000 patient specimens,
with the same equipment and procedures that are used
throughout most of the United Kingdom. Under the
direction of Dr David Telford, a bearded 49-year-old
consultant, there is a chief technician, two seniors,
eight technicians and two assistants, who work around
a rack of pale green benches, "plating up"
and testing for bugs.
All
specimens are routinely checked for salmonella and
campylobacter, but most are not screened for E-coli.
Despite the explosion in the number of infections,
there are still thought to be too few to justify the
time and money. But where the sample is bloody, a
three-day procedure is employed to additionally
search for this bug. The material is incubated
overnight in a yellow "broth", then
scratched onto pink-jelly-coated dishes and left
again until next day. If colonies of suspect bacteria
have grown, some are studied on a slide with
chemicals. Then more are incubated on a plastic
strip, and the following morning the results are
computed.
Matthew's
sample was received on day 4 of his illness and found
positive on day 7. But again there would be questions
about the delay this caused in reaching a diagnosis
of his condition. State-of-the-art methods used at a
few centres around Britain could have slashed his
wait by two thirds. "If we got a specimen at
four or five o'clock this afternoon," explains
Dr Peter Chapman of the public health laboratory in
Sheffield, which uses these techniques, "we
would be able to give you a 99.9% certainty result
that it was E-coli O157 by 9.30am tomorrow."
Why
Matthew never got such service was, like the
decisions to treat him as a non-emergency case,
purely a question of priorities. Chapman uses more
advanced and expensive tests, has specially-trained
technicians and, since investigating an outbreak at a
Sheffield old people's home in 1983, has done
world-class research on the organism. In contrast,
the Royal Lancaster Infirmary does not have the time,
and Telford's main interest is campylobacter. Far
from his staff being seasoned in O157, moreover,
until last September they isolated the bug on fewer
than one occasion a year.
That,
however, was until last September, which saw more
reports of E-coli infections in Britain than in any
other month on record. Another of the organism's
unsolved mysteries is that there is a distinct annual
season for human infections, which begins in May and
peaks in the autumn - and which follows a kind of
"blossoming" of the bacteria in cattle,
which can be monitored several months ahead. As at
hospital labs throughout the UK, the Royal Lancaster
Infirmary's microbiologists' experience with the bug
rapidly and frighteningly grew.
The
most startling aspect was that Matthew's case was by
no means one-off, even in his neighbourhood. Four
days before his illness began, a Morecambe girl, aged
14 months, went down with diarrhoea and vomiting
caused by O157. Forty-eight hours after her, a local
11-year-old boy got the same. On the day before
Matthew's symptoms started, it was a 6-year-old girl,
also in the seaside town. And then on day 8 of
Matthew's illness (the morning after his test
results), Rachael was horrified to discover that Tom,
his brother, also had bloody diarrhoea. In the
following weeks there would be three more children,
making eight, within three miles of Torrisholme.
The
cases had many of the hallmarks of the outbreak in
Scotland, but it was not until the fifth was
confirmed that local doctors were warned to be
vigilant. "We have a small cluster of E-coli
O157 infection in Morecambe," Telford faxed to
65 GPs on day 10 of Matthew's illness. "We are
notifying practitioners in the area so they can be
aware of this when they see children with diarrhoea
and so that they can have a lower threshold for
taking stool cultures and for considering hospital
referral."
Rachael
knew nothing of these other cases. Nor did the alert
help Matthew. Despite the severe risk of
complications, which can be expected in up to one
fifth of cases involving children and old people,
doctors decided not to admit any of those affected to
hospital. Although antibiotics have no effect on the
new E-coli, blood tests and close monitoring can help
guard against possible problems like kidney failure.
Yet these cost money or require scarce beds, so the
advice was to stay at home.
Rachael
was now coping with two sick children and, in the
midst of this turmoil, an environmental health
officer knocked on her front door. His name was
Martin Brownjohn, a tall man, aged 42, who wore a
dark suit and carried a black briefcase, from which
he produced a thick questionnaire. He inspected her
kitchen, looked in her fridge and asked her a string
of questions. Where do you shop? What kind of foods
have you bought? Have you been to restaurants or the
chip shop lately? What kind of milk do you get? Have
you been in the country, on farmland perhaps? Has
your child been near any animals?
It
was detective work, which he added to what he learnt
from the other cases in what was now being called the
"Morecambe cluster". Although the natural
home of the new E-coli is cattle, it has been found
in lamb, poultry, fruit juice, cider, lettuces,
mayonnaise, milk, eggs and many other foodstuffs,
which may be cross-contaminated in processing plants,
shops, restaurants and kitchens. Some infections are
directly from animals, especially at open farms. It
has been found in water supplies and paddling pools.
And up to one in six reports are thought to be like
Matthew's brother's case: spread from person to
person. By comparing the responses from each of the
children's families, Brownjohn hoped to spot a common
source.
The
organism's incubation period is between one and eight
days, so Rachael told him about the visits to
McDonald's and the ice cream parlour, which also sold
hot food. She expected that he would check these
premises, but again the priorities question kicked
in, and neither received a visit. Although ground
beef is so often implicated that O157 has been dubbed
the "burger bug", there was felt to be no
advantage in spending time and public money on
inspecting the restaurants. It was nearly two weeks
now since Matthew had been to either. It was felt
that the moment had passed.
Just
as importantly, none of the other families had
mentioned them as possible culprits. The 14-month-old
girl, it was noted from the questionnaires, had eaten
Asda ham and had recently been on holiday abroad. The
boy aged 11, plus Matthew and Tom had eaten Asda ham
and drunk Thornburrow milk. The six-year-old girl had
drunk Thornburrow milk and eaten sausage from a
take-away. A two-year-old boy had possibly drunk the
same milk. And another, aged 13, worked on a farm at
weekends. One child had nothing that seemed to stand
out as a strong candidate for the cause.
The
ham, mentioned in four of the eight cases, and the
milk named in four or, possibly, five, seemed perhaps
to point to something, but they were treated by
investigators with caution. These were mass-market
products which you would expect to be cited by any
group of families questioned. "It is dangerous
to jump to conclusions," says Steve Mann,
manager of Lancaster's environmental health
department, whose offices overlook Morecambe Bay.
"We thought about the possibility of a low-level
contamination of a nationally-distributed product,
but the investigation was basically getting
nowhere."
Rachael
nagged Brownjohn, who called to see her again, but
soon her insistence that the cause must be found was
superseded by her other concerns. On day 10 of
Matthew's illness (when Telford faxed the warning to
family doctors), the toxins attacking Matthew's
insides were making him so sick, with pain, diarrhoea
and vomiting, that she called her GP, who came
straight away and at last had the child admitted as
an emergency to the Royal Lancaster Infirmary.
"I
can't cope any more," she told him. "I've
run out of bedclothes and everything."
"I
agree," the doctor said, writing his referral
letter. "I think it has gone on too long."
When
they arrived at the hospital, Rachael got the feeling
that opinions about the situation had changed there
also. This time Matthew was rushed into an isolation
room and a nurse arrived almost immediately and, for
the first time, took a blood sample. It went straight
to haematology and the results came back while
Rachael waited by his bed. The analysis showed that
he was suffering from anaemia, with red cells
bursting and fragmenting. It showed that his
platelets - clotting cells - were low, and that his
creatinine and urea - waste products - were much
higher than they ought to be. The diagnosis was
haemolytic uraemic syndrome, a complication of E-coli
poisoning. It is the biggest single cause of kidney
failure in childhood. Matthew was gravely ill.
He
needed dialysis. He needed it right away. But such is
the priority for paediatric renal units that
Lancaster does not have one. There are 13 children's
kidney centres in the UK. A junior doctor hit the
phones. Manchester was full. So a place was booked at
Alder Hey, in the north-eastern suburbs of Liverpool.
Stuart was called. Rachael's sister came for Tom. And
Matthew was wheeled out and into the back of a
waiting ambulance for the 50-mile journey south.
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