- A KILLER IN OUR MIDST
By Greg Callaghan
Its better known cousin evolved in
hospitals, but the latest super-bug can be picked up anywhere. Greg
Callaghan explains why infectious disease experts are calling CA-MRSA our biggest health challenge yet.
Sean Fisher couldn't see the armies of toxic bacteria deep inside his
right thigh, killing off wave upon wave of white blood cells sent forth
to defend him; he didn't know that a
battalion of invaders was charging straight for his lungs, but the
10-year-old felt so ill he probably wouldn't have cared. He'd spent the
night before vomiting violently and enduring painful cramps, cradled in the arms of his mother, Vicky, until dawn.
Only the afternoon before, this normally strong and fit boy had been shifting rocks on the family's idyllic rainforest enclave in Wondecla, 90km southwest of Cairns, with his older brother, Jack, mum and older sister, Terri. Just a couple of hours afterwards he complained of a tingling and burning sensation in his leg, upon which Vicky noticed a
mysterious red rash rising up. Perhaps an insect bite, she thought. But
as the night advanced, she suspected it was something far more
troubling.
Once daylight broke, the 41-year-old mother, whose husband was away working in the mines in
Papua New Guinea, wasted no time. She helped her son, now limping badly
and deathly pale, into the family wagon for the 30-minute drive to the
nearest hospital at Atherton. By the time he was admitted he was
complaining of chest pain, had a fever of 40.3 degrees and his skin was breaking out in dark red, swollen pustules. Meningococcal disease, Vicky fretted. But a
battery of blood tests revealed little more than an infection running
out of control, and with Sean's condition deteriorating, baffled
doctors transferred him to Cairns Base Hospital. There a doctor took a photograph of the rash engulfing his torso, scalp, face and ears.
After almost three days, with the microbe still unknown and medical
options running out, Sean was airlifted to Mater Children's Hospital in Brisbane where he was immediately wheeled to intensive care, hooked up to a
ventilator and drip-fed the antibiotic of last resort, vancomycin.
Doctors put his chance of survival at 30 per cent. "There was
so much infection in his lungs," says Vicky, "that his X-rays were white." With hope draining away she fell to her knees in the hospital chapel, "pleading with God not to take my baby away."
The head of intensive care, after receiving the results from a CT scan and further blood tests, rolled Sean on to his side to examine an abscess on his pelvis. Sean yelled in agony but the specialist had a diagnosis consisting of six strange letters: CA-MRSA, or community-acquired methicillin-resistant staphylococcus aureus, a new super-bug that lives not in hospital wards but in the outside world.
"I'd never heard of it," says Vicky. "I'd
read about golden staph, but not MRSA or CA-MRSA." After
continuing on high-dosage vancomycin, Sean began to make a
slow but steady recovery. When he was discharged from hospital five
weeks later, he had only 30 per cent lung capacity and was learning to
walk again. Only now, four months later, is Sean anywhere near being
the active boy he once was.
It turns out Sean is one of the lucky ones. Sydney teenager Reis
Gray wasn't so fortunate. The strapping 190cm 17-year-old returned home
from guitar lessons one Tuesday evening sniffling and feeling
lethargic. The next day his mother, Julie, drove him to the local GP,
who prescribed a course of antibiotics. When his colour didn't improve over the next 24 hours, a worried Julie phoned her mother, a retired nurse, but Reis insisted, "I'm fine, Mum. I don't feel any pain."
But he wasn't fine and on Friday morning Julie dragged him out of bed
("I just need to sleep," he moaned) and drove him to
the GP, who took his pulse and immediately called an ambulance. Just
before Reis was intubated in accident and emergency at Westmead Hospital, he asked, "Am I going to be all right, mum?"
"Of course you are, sweetheart," Julie replied without hesitation, genuinely believing that in a Sydney hospital in the 21st century, brimming with cutting-edge technology, that her healthy, outdoorsy son, who hadn't been in a hospital since he was born, would make a swift recovery. But it was to be the last time she heard Reis's voice.
Astonished doctors took one look at his X-rays and scheduled a
double lung transplant - three-quarters of Reis's lung tissue was
missing, eaten away by the bug. But before any transplant they had to
halt the runaway infection in its tracks. They launched a barrage of antibiotics against it but the infection shook them all off like confetti.
This bright, gregarious young man - who enjoyed footy, fishing, and jamming with his dad, Warren, in
the garage - never regained consciousness. Which didn't stop him
battling his insidious assailant for 24 more days, until his heart
finally gave out. "He was the baby of the family, the one who
always made us laugh," says Julie, who has two older children,
Josh, 20 and Jessica, 23. "He had his whole life ahead of
him." In the middle of the dining table where we are talking, Reis smiles back at us from a white-framed photograph, a handsome young man with a lick of chestnut hair tumbling over his forehead. On a mantelpiece opposite stands a shiny wooden box. Inside rest his ashes.
YOU'VE HEARD ABOUT GOLDEN STAPH: go into hospital, come out sicker. Every year in Australia, this elusive microscopic foe infects at least 7000 patients, of whom about 2000 (or one-in-three) will die, a figure now exceeding the national road roll - and climbing. Every time you're opened up on the operating table or connected to a drip there's a risk staphylococcus aureus will slip into your bloodstream, making you sicker than you were before admission.
The form of staph you don't want to get is the one with the ungainly
name, methicillan-resistant staphylococcus aureus, or MRSA, now immune
to all but the most potent antibiotics. Get a serious MRSA infection and you'll be seriously ill; add it to a pre-existing condition and you may be fighting for your life. There isn't a hospital in Australia that hasn't had an outbreak of MRSA; it now represents up to a third of staph infections and it's become a massive problem in British and American hospitals. Sydneysider Alison Sayer, a victim of the 2005 terrorist attack in London, nearly lost her right foot - not to a bomb but to an MRSA infection she picked up while at St Mary's Hospital after surgery to repair her knee.
But MRSA has a new renegade cousin -
one that hits you where you live. Community-acquired MRSA could be
lurking on someone's hand when you shake it, their face when you kiss
it, on a tea towel, on your computer keyboard, a piece of gym equipment, on a meeting room table. In short, you can catch it anywhere at any time. Those involved in contact sports or prone to cuts and scrapes, such as children, are at special risk.
Never heard of CA-MRSA? Neither have some GPs and nurses in Australia. It only popped up in a few isolated cases about 10 years ago in remote indigenous communities in Western Australia, the result of a
lethal combination of poor hygiene, skin disease and the rampant
overuse of antibiotics. But its three main strains have now spread
through all our capital cities and, unlike
the hospital variety, which mostly affects elderly and infirm patients,
they prefer younger, fitter hosts. CA-MRSA is also much more easily
transmitted and can be armed with the mother of all toxins, PVL, which
can kill within a matter of days, usually from a necrotising infection that eats away at skin, bones and lungs.
In the US, strains of this savage little bug
have struck down football players from the Cleveland Browns, the New
England Patriots and the St Louis Rams, and forced trainers to
disinfect equipment almost hourly. Schools have been temporarily shut
down. All up, MRSA takes at least 90,000 lives in the US each year, making it a greater killer
than AIDS and prompting headlines such as "the ticking time
bomb". Stories abound on the internet of young people dying or
becoming seriously ill and some sufferers have uploaded pictures of
their gaping wounds on YouTube.
IT'S TEMPTING, OF COURSE, to toss CA-MRSA into the health-scare
basket along with SARS, bird flu and mad cow disease. It's only when
you listen to infectious disease specialists across the country that
you realise this disease is likely to represent medicine's number-one
nightmare in the next decade.
Declares John Turnidge, a professor of molecular science at the University of Adelaide: "CA-MRSA is the most lethal of the super-bugs. There's a Nobel Prize in
this for whoever cracks the formula of beating it." Dr Peter
Collignon, director of the infectious diseases unit at The Canberra
Hospital, says: "If we don't do something to stop this bug
from spreading, we're going to be hit on the back of the
head". Keryn Christiansen, head of microbiology and infectious
diseases at Royal Perth Hospital: "CA-MRSA isn't just a
new problem - it's the biggest problem." Dr Graeme Nimmo,
director of microbiology for Pathology Queensland: "Nothing
like this has ever been seen. We're seeing more and more cases and it
could erupt into an epidemic."
The odds of catching CA-MRSA are still low. But what's alarming the experts is how quickly it is spreading in Australia and how the epidemic is unfolding in the US. A study by Pathology Queensland found there was a sevenfold increase in cases over the past seven years. "Now that," says Nimmo, "is a major increase."
"We're seeing the first deaths," says Collignon, "and at Canberra Hospital we now have more infections from
CA-MRSA than the hospital type. We need to stop it before it gains a foothold in the community." Some Sydney and Brisbane hospitals are reporting outpatients with CA-MRSA as many as three times a week.
Getting a handle on the number of CA-MRSA infections is devilishly difficult, because there isn't a national register of the hospital-dwelling MRSA, let alone the community-acquired one - a sore point with infectious-disease experts. At least a third of us, or about 8 million Australians, are walking around with golden staph up our noses, or crawling over our hands. For most, it's a silent, harmless passenger, one that may pop up in a minor infection such as a boil and be cleared with antibiotic cream. It's only when CA-MRSA goes helter-skelter in your bloodstream that it becomes life-threatening.
Mention the words "flesh-eating bug" and you
immediately think of arms and legs turning black - meningococcal
disease - but, in fact, staph-like complaints are at least 30 times more common. And unlike meningococcal, for which is there is a
vaccine for the group C strain, staph-type infections continue to
outwit doctors. "This is much bigger than meningococcal
disease," says Turnidge. "Staphylococcus kills many
more people than meningococci and we don't have a vaccine in the offing."
Babies are especially vulnerable - particularly if they are laid on
shared furniture such as couches, where the bug can survive for up to
six months. Disturbingly, a UK study found that 50 per cent of cot death victims had elevated levels of CA-MRSA, which can thrive in stale mattresses. The findings may explain why cot death, or sudden infant death syndrome, is more common in
second and subsequent children. "This organism has
tremendously good abilities to survive over long periods,"
says Collignon. "Mattresses shouldn't be used for more than
one child."
Another recently noted trait of CA-MRSA has been its spread within
families. Adelaide mother Annette Simpson*, her husband Joe and their
two sons, James, six, and Ben, four, have all been struck with serious
CA-MRSA skin infections. In January, James was hospitalised for the second time after the bacterium spread to his bones; it was only halted after a
long course of IV antibiotics. "He fell off his bike on the
Saturday, and on Sunday he couldn't walk," says Annette. Back in 2005, James developed a
golfball-sized boil on his left leg, which had to be surgically
drained, and since then every member of the family has had at least one
skin eruption of CA-MRSA. "I had one the size of a
50-cent piece on my backside,"; says Annette, who now wears
latex gloves when handling food and cleaning. "We've learnt to
go straight to hospital at the slightest sign of an
infection."
WHEN DR JOHN MERLINO tilts a plastic petri dish teeming with 100 million CA-MRSA bacteria under a
fluorescent light, it's easy to understand why it's nicknamed
"golden staph". Five tiny antibiotic pills are
immersed in a sea of golden particles; two have repelled the bacteria (marked by a force field around them) and the remaining three are completely besieged (the antibiotics rendered impotent by the bug). In
this culture - which Merlino orders up for any patient fighting an
onslaught of antibiotic-resistant microbes - he can identify the drugs
beating the bugs and those that have already surrendered.
"This is Darwinian survival of the fittest in
action," says the 48-year-old microbiologist from Sydney's
Concord Hospital. "All this microbe is trying to do is survive
and reproduce, just like us." Overuse of antibiotics helps to
breed hardier, stronger bugs in two ways, he explains. First, the laws of natural selection dictate that when a handful of bacteria survive a
mass assault by antibiotics, they pass on their resistant genes to the
next generation. Second, since antibiotics wipe out competing bacteria
species, they leave a near-empty field for drug-resistant strains to thrive.
If this dish teeming with CA-MRSA were to burst over my hand suddenly and the bacterial invaders seep into my bloodstream via a small paper cut or sore, I'd start feeling crook within a matter of hours. Within 24 hours I'd be breaking out in vivid red, weeping sores, and feeling weak. Until this point a
standard course of workhorse antibiotics might still wipe out the
infection, but if it began to run rampant I'd be seriously ill with
pneumonia within two or three days, at worst fighting off a bug that could be devouring my lungs at a rate of 15mm an hour. If heavy-duty IV antibiotics failed to arrest the infection it would all be over.
Or maybe I wouldn't get so much as a
pimple or sniffle. My fate would depend on my physiological make-up,
the strength of my immune system, and the bacterial load that enters my
bloodstream. This is one of medicine's biggest mysteries: why is it
that one person can walk around with a throat or hand full of disease-causing bacteria without getting sick but then transmit it to another who becomes mortally ill?
Scientists are convinced
that it's not just our genetic make-up - the Human Genome Project identified a paltry 20,000 genes, not many more than it takes to make a fruit fly - but its chemical dance with the hordes of bacteria that make up our bodies, exceeding the total number of cells by about 10 to one.
A microbiologist for
more than 20 years, Merlino is no alarmist. But he believes CA-MRSA is one bug we can't afford to take lightly. Even recent headlines and TV news stories about a new super-bug, VRE, or vancomycin-resistant enterococcus, worry him and other disease detectives far less than CA-MRSA. Why? Because in hospitals at least, the seawall against the rising tide of drug-resistant bugs is proper hand hygiene, the subject of a national campaign to be rolled out this year (the recent Garling inquiry in NSW strongly recommended sacking doctors who repeatedly failed to wash their hands).
Being in the outside world, CAMRSA is
neither so easily controlled nor so selective about whom it strikes.
What disturbs Merlino about the community strains of MRSA, he says, is
that they have features allowing them to colonise skin more effectively
than their hospital cousin.
For years, public health officials have been raising the alarm about how our over-reliance on antibiotics is breeding a generation of super-bugs increasingly resistant to the medicines designed to kill them. While our
consumption of antibiotics has dropped, we are still the world's
biggest net consumer after the number-one hypochondriac, France.
Studies now suggest that the more antibiotics you pop throughout
your life, the more vulnerable you may be to infections such as CA-MRSA
as you weed out susceptible germs but promote the growth of their
hardier cousins. Adults are
still given antibiotics for viral conditions such as colds or flu, even
though the drugs are useless against viruses. Many of us stop taking
the antibiotics when our symptoms go away
but before an infection is completely cleared up, which allows the
partially resistant microbes to flourish. And experts warn that too
many antibiotics are fed to children for complaints that would have
cleared up on their own.
Turnidge says he has been "rattling the antibiotic cage
for over 20 years", but sees only inaction by governments. "Continuing high antibiotic use and the emergence of more
resistant strains is a recipe for disaster," he warns. It's a simple numbers game, says Collignon, who believes we need to cut our
consumption by 50 per cent or more. "If we use half the amount
of antibiotics, the resistance to antibiotics will be halved."
Antibiotics are precious drugs, he insists, "to be kept in reserve until we absolutely need them."
The age of antibiotics has given way to the age of anxiety, where drugs
that once conquered everything from pneumonia to tuberculosis are
losing their punch. Even vancomycin, whose name is derived from
"vanquish", is struggling to fight the new mutating
forms of MRSA. Consider this: the Centres for Disease Control in
the US reports that the number of people dying from hospital infections
jumped almost tenfold between 1992 and 2005 - from 13,300 to 100,000.
Even worse, research into new antibiotics has been drastically
neglected and underfunded for almost 30 years. "The money is in the pills you take for long periods, like those for blood pressure or depression. It's not in antibiotics, which you take for a brief period of time," laments Turnidge. Notes Christiansen: "For some organisms, we have absolutely nothing in the pipeline in the way of antibiotics, which is very troubling."
If there's nothing left to prescribe, where will we be? At worst, back to the days before penicillin became widely available in
the mid-1940s, when staph infections had an almost 90 per cent
mortality rate, when healthy young people such as Australian boxer Les
Darcy (1895-1917) could die of complications from an infected tooth,
and silent movie star Rudolph Valentino (1895-1926) from an infection
after a perforated ulcer.
Already the war against antibiotic-resistant drugs is an increasing
drain on the health-care system. At Royal Perth Hospital an outbreak of
the killer superbug VRE in 2007 cost millions to eradicate in a sweeping "search and destroy" mission, says Christiansen. "We were successful in
ridding the hospital of VRE - but it cost more than $2.7 million.
That's one hospital and one outbreak of the disease."
There is some good news. In the US, scientists are developing a new class of antibiotics that targets a
pair of enzymes the microbes depend on to copy their genes and
reproduce. And mercifully, most cases of CA-MRSA are still susceptible
to standard antibiotics. The hospital variety, meanwhile, is still
responsive to powerful intravenous antibiotics such as vancomycin,
linezolid and daptomycin. But the operative word here is "still". Most experts agree that we're losing the war
against microbes and unless a breakthrough
happens soon, the formidable barriers we have built against disease
over the past 70 years will start falling down.
SO SLIPPERY A BUG IS CA-MRSA THAT even
the most diligent hand-washing and surface sanitising are no guarantee
against becoming infected, as Jan Skally, an intensive care nurse at
Royal Perth Hospital, tragically found. Jan returned home from a concert late one Friday evening to find her 60-year-old husband Ed in
bed, breathless and nauseous. He'd complained of feeling off colour the
day before, but dismissed his sniffles and achiness as the first signs
of a cold or flu. Jan checked his pulse and called a
doctor, but as the clock ticked away it was apparent Ed was becoming
worse. After dressing him and carrying him to the car, Jan drove to
Royal Perth's emergency department, where Ed was wheeled into the
high-dependency area.
At 4.30am Jan drove home to pick up a
few things for Ed's hospital stay. She was gone for no more than an
hour, but when she returned Ed had already been intubated and was being
moved to intensive care. A bronchoscopy showed that Ed's lungs were riddled with holes and flooded with pus; a specialist described it as one of the most virulent pneumonias he'd ever seen. Ed didn't respond to a raft of antibiotics, including a dose of vancomycin, and suffered multiple organ failure within 24 hours. He died at 8am that Sunday.
Last month, Jan and Ed, the parents of two children in their late 20s, would have celebrated their 34th wedding anniversary. "I never got a
chance to say goodbye," she says. "The last time I
saw him smile was at the hospital, just before I returned home to grab
the clothes, and I had no idea that this would happen. In all my years in intensive care, I'd never seen anyone deteriorate that fast."
When Jan first heard the letters MRSA from the specialist handling Ed,
she imagined with horror that she may have infected him with the bug.
However, it wasn't the hospital-borne pathogen that killed him but an
outside strain, CA-MRSA, loaded with the telltale PVL toxin.
"Where did he get it from?" she asks. "I
don't know. I wash my hands constantly, not just in the hospital but when I'm at home."
Wherever Ed caught CA-MRSA, it's highly likely he passed it on to his wife, because three months after his death, Jan noticed a
red boil on her thigh. She cleaned and dressed the wound but the
infection spread within three days and her leg turned black between the
knee and pelvis. Because she was a nurse,
Jan had to be decontaminated with antiseptic washes and baths for 10
days, and only after 10 weeks of repeated testing was she allowed back
into Royal Perth. "This is really the most frightening
bug, "she says simply.
When you hear stories like this, what's a
person to do? Certainly, doctors aren't suggesting avoiding hospital if
you need an operation. Nor do they advocate refusing essential
antibiotics to those who are seriously ill. It's more the casual dosing
- for sore throats and mild infections (mostly caused by viruses,
against which antibiotics are useless) - that create the problem.
Staying clean and washing hands is a good protective measure but not foolproof. Ultimately, the best win will be a vaccine, but that's not even around the corner yet.
In the meantime Nimmo, Collignon, Christiansen and others are calling for MRSA and CA-MRSA to be made a
notifiable disease Australia-wide. "We urgently need good
national figures to keep tabs on how the infection is
spreading," says Nimmo (so far, only in Western Australia is it mandatory for MRSA to be reported). "We can't get the Federal Government interested in
this at all," says Collignon, who is worried about the
"potentially catastrophic consequences" of CA-MRSA
infiltrating the medical system and combining its genes with the
hospital form of MRSA.
As a bacterium, CA-MRSA may still be in
its youth, but evidence suggests it's growing up fast. "What
we're looking at here," says Collignon, "is a strong, well-designed organism that's doing whatever it can to protect itself"
He pauses for a moment and then muses: "This is not going to go away."
______________________________
"* Not their real names. Senior editor Greg Callaghan's
previous story was "Stadium rockers"(January
31-February 1).
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