Bugs in our systems: our future resistance

By Martin Johnston

Infectious disease experts say we use far too many antibiotics and this is a cause of rising resistance of bacteria to treatment. Martin Johnston reports on how this is limiting our access to health care.

Mark Thomas says  increasing antibiotic resistance should be of great concern. 
Photo / Dean Purcell
Mark Thomas says increasing antibiotic resistance should be of great concern. Photo / Dean Purcell

The resistance of superbugs to antibiotics may seem like a horror show of the distant future to many people. But for one cancer patient in Auckland it meant that he could not have a standard medical check.

Welcome to the antibiotic resistant present in which, specialists say, medical procedures will become increasingly restricted - unless we cut back on antibiotic use, stop using them inappropriately, develop more new antibiotics and do more to avoid bacterial infections.

Doctors would not do the test on the elderly cancer patient because of the risk it could kill him with a nasty superbug that is resistant to many antibiotics. He was on a surveillance programme to monitor a slow-growing tumour, as an alternative to surgery or other treatments that risk significant complications.

He was also found to be a carrier of the multi-drug-resistant version of E. coli bacteria known as one of the NDM (New Delhi metallo) beta-lactamase strains.

Laboratory tests showed it was resistant to eight types of antibiotics.

He had recently visited India, although did not have health treatment there. He was booked at Auckland City Hospital for a biopsy - the removal of tiny samples of tissue from his prostate tumour. This was to be done with the biopsy needle guided through an ultrasound imaging device in the rectum.

The procedure carries the risk that some bacteria that are harmlessly in the bowel will be pushed by the needle through the bowel wall and cause a potentially fatal blood infection. Preventive antibiotics are given to reduce this risk.

In 2012, the hospital started pre-screening prostate ultrasound-biopsy patients to see if they carried E. coli that were resistant to a particular antibiotic, which was how the multi-resistant bacteria were detected in the man in question.

Doctors and microbiologists outlined the case in a research letter to the Journal of Antimicrobial Chemotherapy. They recommended tailoring preventive antibiotics based on the kinds of bacteria detected in each patient - but also called for a re-evaluation of the risks and benefits of rectal ultrasound prostate biopsies.

" ... for patients colonised with extremely resistant organisms such as NDM-producing E. coli, options for targeted prophylaxis [preventive antibiotics] and potential treatment may be so limited that the benefit of proceeding with biopsy may itself need to be called into question."

This case shows how multi-resistant super-bacteria are affecting health care, limiting options for patients to have standard tests and treatments. And it's likely to get worse. International experts warn of a looming post-antibiotic era with completely untreatable bacteria.

Experts writing in the New Zealand Medical Journal say the risk/benefit balance may swing against organ transplants, bone marrow transplants and artificial hip and knee joints if an increasing percentage of procedure-related infections are caused by untreatable bacteria.

"Increasing antibiotic resistance therefore threatens a very wide range of current medical and surgical practices," wrote Associate Professor Mark Thomas and his colleagues. "It should be of great concern to the community and to all healthcare workers."

Dr Thomas, an Auckland University researcher and infectious diseases physician at Auckland Hospital, said completely untreatable bacteria were very rare here - and tended to have bad outcomes.

Research by the Health Quality and Safety Commission has found many experts agree that antibiotic overuse and inappropriate use is a cause of growing resistance. Other factors they cite are overcrowded homes, contamination of hospitals and rest homes, and poor hygiene.

In New Zealand, the effects of antimicrobial resistance turn up in everyday community healthcare. The topical antibiotic Bactroban used to be sold as an "over-the-counter" treatment for boils, school sores and other skin infections. However, because of increasing resistance to it, particularly of strains of staphylococcus aureus bacteria, it reverted to being available only on a doctor's prescription. Several strains of that bacteria have evolved resistance to penicillin-based antibiotics.

Rates of another group of resistant bugs - ESBLs or extended spectrum beta lactamase-producing bacteria - have also risen sharply, to 195.7 cases per 100,000 a year.

More than 20 per cent of bacteria in community laboratory samples from patients with urinary tract infections are now resistant to the standard first-line antibiotic and are treated with another medicine.

In hospitals, resistant bugs mean longer, costlier stays with patients having to be injected with drugs that are harder to tolerate, rather than swallowing pills.

Likewise in sexual health treatment.

"Gonorrhoea used to be treated with oral [pills]. Now we have to inject people with an expensive antibiotic," said Professor Bruce Arroll, a GP and senior lecturer at Auckland University. "It's much more dangerous to inject someone.

"Fortunately the development of antibiotic resistance is relatively slow, but it may get to a point where it takes off like wildfire [and] then we would be in real trouble."

The Thomas paper shows New Zealand's use of antibiotics by community-based patients rose by 43 per cent from 2005 to 2012 and is now in the same league as Spain and Italy.

The researchers suggest New Zealand's slowing rate of increase from 2008 may be due to the centre's advice to doctors. They note a "dramatic reduction" in two types of antibiotic in 1999 and 2000 were associated with Pharmac's Wise Use of Antibiotics campaign.

Pharmac said the campaign was no longer actively promoted, but the agency funded the Best Practice Advocacy Centre's journal and was involved in writing criteria to properly target the use of many antibiotics.

But Dr Thomas and his colleagues urge a frontal attack on antibiotic over-use, such as by adding it to Health Minister Tony Ryall's headline Health Targets, which have achieved a remarkable degree of compliance by district health boards.

Mr Ryall bluntly dismissed this idea. His ministry explained that while a health target was unlikely, officials were "in the early stages of considering the usefulness of benchmarking of antibiotic prescribing against best practice".

This means setting an agreed standard and comparing providers - kind of like a target, but without all the public attention, newspaper adverts and so on which are the motivating magic of the minister's medicine. To support the call for a target, the Thomas paper gets the ball rolling with data showing that in the health district with the highest use, Counties Manukau, community-based patients' antibiotic use is 49 per cent higher than in the lowest-using district, the West Coast of the South Island.

Counties Manukau DHB said it was concerned about the amount of antibiotic use in its community and wanted to reduce inappropriate prescribing, but there were reasons for variations between areas. Its higher rates might be linked to its greater levels of deprivation, obesity, diabetes and smoking leading to greater rates of infection needing treatment.

Dr John Cameron, clinical director of Procare, a primary health organisation serving Counties Manukau, said a health target aimed at the area's high use could create a perverse incentive leading to greater illness through inappropriately withholding antibiotics.

"The majority of inappropriate use is the adults who believe that having had a cold for three days equates to the need for antibiotics.

"I know I have got my patients to the right place when I have to convince them to actually take antibiotics."

Super-bug warning sounding for decade

Health experts have been trying to shock the world into action over super-bugs for a decade.

With growing resistance of bacteria to antibiotics and a lack of new antibiotics in development, Britain's chief medical officer last year demanded the "ticking time-bomb" of antimicrobial resistance be treated as seriously as "catastrophic terrorist attacks" and other civil emergencies.

Professor Dame Sally Davies warned of an "apocalyptic scenario" of Britain's health system rapidly falling back two centuries if new efforts were not made in "the war" against bacteria, viruses, fungi and parasites.

"If we don't act now, any one of us could go into hospital in 20 years for minor surgery and die because of an ordinary infection that can't be treated by antibiotics."

Her frightening report was followed up this year by an assistant director-general at the World Health Organisation, Dr Keiji Fukuda, who said: "Without urgent, co-ordinated action ... the world is headed for a post-antibiotic era, in which common infections and minor injuries ... can once again kill."

But some experts view the war on rising antimicrobial resistance like global warming: the mass of individuals whose reduced use of antibiotics (or fossil fuels) could make a difference is largely indifferent to their effects on a future that will be inhabited by other individuals. So they are trying to make the connections for us between our antibiotic use now and the health treatment we may need but not be able to receive in our lifetime.

The WHO reported in April that antibiotic resistance was a major global threat to public health. Resistance to "last resort" antibiotics was found in all regions of the world.

Dr Fukuda said: "Effective antibiotics have been one of the pillars allowing us to live longer, live healthier, and benefit from modern medicine. Unless we take significant actions to improve efforts to prevent infections and also change how we produce, prescribe and use antibiotics, the world will lose more and more of these global public health goods and the implications will be devastating."

Among other recommendations, the WHO called for better monitoring of antibiotic resistance, better hygiene to prevent infections, greater co-operation to foster development of new antibiotics, and more careful use of antibiotics, such as taking them only when prescribed by a doctor.

- NZ Herald

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