Scourge of the superbug

The rise of the superbug. Photo / Dean Purcell

A new generation of superbugs, fast developing resistance to all the tried-and-true antibiotics, has reached New Zealand shores. And hospitals are scrabbling for a solution.

In Sci-Fi movies it never turns out this way. We are used to the classic storyline in which a cruel, bizarre invading enemy is banished after a valiant fight. But in this case the invader morphs into a new, stronger foe - and the battleground is our own bodies.

In 1981, Professor Peter Davis, husband of Helen Clark, made a jubilant claim in a textbook on medical sociology: "Infectious diseases have been reduced to insignificance." Yet, two decades on, about 120 New Zealanders die from rheumatic fever annually and last year there were 671 people diagnosed with tuberculosis, three of whom died. These are diseases we associate with the 19th century rather than modern times - and they are still killing us.

What's more, there is a rise in the Incidence of diseases with futuristic names such as NDM-1. New and virulent bugs that can spread as quickly as it takes a flight to get from New Delhi to Auckland are alarming the medical and scientific professions.

The increasing number of these infectious disease cases is placing a huge burden on our health system. An extra 20,000 people are admitted to hospital each year because of infections.

This is why the country's experts in the field of infectious diseases gathered this week at the University of Auckland for a Superbugs Symposium, hosted by the Maurice Wilkins Centre for Molecular Biodiscovery, to consider the threat facing New Zealand and what can be done about it.

Auckland clinical microbiologist Dr John Freeman says we are not at the brink of biological Armageddon - the invasion of an unbeatable superbug that will decimate the population.

But there is a real concern that common bugs will become resistant to antibiotics and therefore very difficult to treat. This can lead to life threatening situations, but it more often means people suffer from persistent minor infections and need to be hospitalised to get over them.

Hospitals - by far the most common Place to contract a superbug - are the danger zones. Medical equipment such as catheters, combined with open surgical wounds and the use of antibiotics, create a potentially lethal cocktail. And once they have a toehold, infections tend to spread quickly in a hospital environment where there is a lot of person- to-person contact.

Over the past 10 years superbugs methicillin-resistant staphylococcus aureus (MRSA) and extendedspectrum beta-lactamase (ESBL) have wrought havoc on the health of thousands of New Zealanders. Their prevalence is increasing in the community.

North Shore hospital has the highest rate of ESBL in the country: about a third of its patients are carrying the bug at any one time. Since the first outbreak in July 2007, 4000 patients have been identified as carrying ESBL. All wards of the hospital are affected. Most people carry the superbug with no apparent effect, but about 12 per cent develop infections that can lead to prolonged hospital stays, sometimes in intensive care, and more doses of antibiotics. The superbug has been associated with deaths in high-risk patients.

As hospitals and Environmental Science and Research (ESR) monitor and try to control the known superbugs, new ones are entering the country.

One of the newest is NDM-1,which stands for New Delhi metallo-beta-lactamase. The bacterial gene was first detected last year, when a Swedish patient caught it after cosmetic surgery in New Delhi. In August, scientists warned in the medical journal The Lancet that NDM-1carries the potential risk of "becoming a worldwide health problem".

In an age of global travel, nothing stays isolated for long. In just a few months, the superbug has spread to the United States, Canada, Brazil, Belgium, the Netherlands, the UK, Pakistan, Austria, France, Germany, Oman, Kenya, Australia, Hong Kong, Taiwan, Japan and Singapore, and killed more than 20 people.

The killer has also reached our shores. There have been three cases of NDM-1 confirmed and one probable case diagnosed in New Zealand since last December. In all four cases, the patients had recently returned from India and could not be treated by antibiotics.

Another superbug causing scientists and doctors concern is clostridium difficile (C. diff) which takes hold in vulnerable hospital patients who have been treated with antibiotics, causing severe diarrhoea and vomiting. It can be fatal.

C. diff is behind Britain's worst hospital superbug scandal, in which it was linked to the deaths of 331 people in two years at Maidstone and Tunbridge Wells hospitals in Kent. The hospitals now post weekly infection rates on their websites. This week Maidstone recorded three cases of C. diff.

This particular superbug is a sporeforming organism, which means it can easily contaminate an environment. As its prevalence spreads around the world, particularly in the US and Europe, New Zealand hospitals are seeking ways to keep contamination levels down.

Dr Sally Roberts, clinical director of LabPlus, the Auckland District Health Board's laboratory testing service, says the key is getting the basics right.

"We need to change our backyard," she explained to the Superbugs Symposium. "It's unacceptable for patients to come to hospital and get a hospital-based infection."

Roberts says only 35 per cent of medical staff follow proper hand hygiene guidelines. "There are all manner of excuses," she says. "Last week I was asked for evidence of why you should clean your hands before contact with a patient." Roberts says hospitals are on tight budgets and cleaning is considered one cost that can be cut - but the impact on patient health is huge.

In July 2007, Auckland Hospital was hit with an outbreak of Vancomycin-resistant enterococcus (VRE), an antibiotic-resistant bacterium that attacks the urinary tract, blood, heart and large intestine. When VRE struck, there was one cleaner for every two wards. A toilet that should have been cleaned every four hours was cleaned just once or twice in 24 hours.

Roberts describes the hospital as being "filthy". So she and senior nurses stripped every bed and cleaned every bed rail, throwing out soft furnishings that could harbour germs.

The rate of infection has now greatly diminished. In the past three years there have been 190 VRE cases at Auckland City Hospital but 165 of these were in the first year.

A number of scientific projects are investigating how to limit or eradicate the risk of infection. These include some by the US military, which is concerned about rampant infectious diseases disabling troops in Iraq.

Studies have shown copper is resistant to bacteria and hospital furniture made from copper could greatly reduce the spread of disease. But we are unlikely to see expensive new furniture turning up in our wards.

The most cost-effective defence against the spread of superbugs is making sure nurses and doctors are doing their jobs right. An audit of the appropriate use of catheters at North Shore hospital in the wake of the ESBL outbreak revealed that up to a third of catheters were left in for an inappropriate length of time, increasing the chance of infection.

It should come as no surprise that the very young and the elderly are the most vulnerable to infectious diseases. But one disease has shocked scientists because it shouldn't even exist in New Zealand. It is not a new superbug. It is a Third World disease, which is eminently avoidable at minimal cost.

Rheumatic fever is prevalent among Maori and Pacific peoples: Maori are 23 times more likely than Pakeha to contract it; Pacific peoples are 50 times more likely.

This disease has been almost eradicated in most developed nations yet, in some parts of New Zealand, the rates are among the highest in the world.

It starts innocently enough, with a streptococcal throat infection. But if that is left untreated it can lead to chronic rheumatic heart disease through damaged heart valves. Sufferers can be hospitalised for weeks and on penicillin for years afterwards.

The Heart Foundation's medical director, Nathan Sharpe, believes rheumatic fever should be eradicated in New Zealand by 2015. "The fact we still have it is an embarrassment, it's intolerable," he says. "It indicates that maybe we don't care enough."

Michael Baker, an associate professor at the University of Otago's Department of Public Health, calls the situation "a national disgrace". His recent research on the subject reveals that overcrowding is a major risk factor in contracting the disease.

Ten years ago, the rate of rheumatic fever in the Whangaroa area of Northland rivalled that of Aboriginal communities in Australia. Northland medical officer of health Dr Jonathan Jarman and the local community started a prevention programme in February 2002 to address the issue. Children with sore throats were swabbed at school and, if they were found to have strep throat, they were given antibiotics. The programme has been a great success. Children are still being swabbed, but the last recorded case of rheumatic fever in Whangaroa was in 2002, eight days after the programme started.

Jarman says there is a connection between rheumatic fever and the new superbugs. The increase in superbugs' resistance to antibiotics is partly attributed to overuse or unnecessary use of antibiotics. Jarman says some doctors will not prescribe antibiotics when needed because they are concerned about the spread of superbugs. A Pharmac campaign promotes the "wise use of antibiotics", cautioning doctors against overprescribing them.

Jarman and his colleagues have written a letter opposing this campaign because, they believe, there is a chance a life-threatening condition will go untreated.

"We feel that the Pharmacantibiotic wise use campaign has selectively disadvantaged Maori and Pacific Island children and put them at risk from rheumatic fever," he says.

White the medical profession argues about the balance between treatment and overtreatment, the fight goes on in labs and wards around the country to keep the threat at bay.

"The concern should be with those who are able to do something about it," says microbiologist John Freeman. "It's alarming enough for us in health care, epidemiology, government and scientific fields to be pitting our resources against it."

One option for fighting the superbugs is a so-called "deep cleaning" programme similar to that introduced in the UK at a cost of $130 million.

The programme, which came under intense scrutiny because of its cost, involves intensive cleaning measures in hospitals - generally the emptying of hospital wards, dismantling of beds, cleaning of light fittings and behind radiators using steam and ultrasonic cleaners.

Waikato Hospital spokeswoman Mary Anne Gill says a similar programme is being looked at by her DHB. "It is expensive but patient safety is also crucial," she adds.

Counties-Manukau infectious diseases physician Dr David Holland says he has heardtheUK's programme has worked but at the expense of other services because it is so resource intensive.

To implement a similar regime in New Zealand hospitals would require significant government funding. That appears to be a long way off: Health Minister Tony Ryall's office says it requires a ministry recommendation; his ministry says the initiative must come from the DHBs; DHBs say they need money from the Government. Round and round.

Whatever new measures, new drugs and new technologies developed to ease the problem, Holland says we're in this for the long run. "It's a constant battle to deal with the spread of these germs," he says, "and one that is not going to go away."

SUPERBUGS - THE FACTS
Superbugs are micro-organisms that are resistant to antibiotics. When doctors talk about superbugs they can be referring to either bacteria or enzymes.

C.diff
Clostridium difficile is a bacterium that normally lives in the gut in balance with other "gut flora". Because it is resistant to antibiotics after treatment with penicillin it can colonise and overpopulate the colon causing painful bloating and diarrhoea.

MRSA
Methicillin-resistant staphylococcus aureus is any antibiotic-resistant strain of the common staphylococcus bacterium that can attack the respiratory tract, open wounds, intravenous catheters and the urinary tract. In worst-case scenarios this bacteria can develop into necrotizing fasciitis.

NDM-1
New Delhi metallo-beta-lactamase is another enzyme created by a number of different bacteria, resistant to even the most powerful class of antibiotics known as carbapenems. The gene that expresses this enzyme can be carried and transferred between different bacteria. NDM-1 has been called a "super superbug" because there is no known treatment.

VRE
Vancomycin-resistant enterococcus is an antibiotic-resistant bacteria that attacks the urinary tract, blood, heart and large intestine.

ESBL
Extended-spectrum beta-lactamase is not a bacterium; the term denotes the capacity of a bacterium to produce an enzyme making it resistant to first-stage antibiotics such as penicillin and its derivatives.

- Additional reporting: Leigh van der Stoep