Antimicrobial resistance is a growing concern worldwide as disease-causing microbes evolve resistance to the faithful drugs we use to kill them.
As part of World Antibiotic Awareness Week, the Ministry of Health is encouraging New Zealanders to take advantage of an ‘Antibiotic Amnesty’ to safely dispose of old antibiotics at pharmacies to reduce the spread of antimicrobial resistance.
Earlier this year, the World Health Organization (WHO) listed antimicrobial resistance as one of the top 10 threats to global health, as we may lose the ability to banish once-common diseases like pneumonia, tuberculosis, and gonorrhoea.
Driven by overuse in animals and people, the number of people being infected by multi-drug resistant organisms (also known as superbugs) has been on the rise in recent years, with most infections occurring in hospitals.
Although superbug infections in New Zealand are rare, news emerged last month that a person in Canterbury died after contracting a superbug in an overseas hospital.
To mark World Antibiotic Awareness Week, the SMC asked experts about the current state of antimicrobial resistance in New Zealand. Feel free to use these comments in your reporting.
Dr Joshua Freeman, Clinical Director Microbiology and Virology, Canterbury District Health Board, and Chair, New Zealand Antimicrobial Susceptibility Testing Committee (NZNAC), comments:
How many cases of drug-resistant or multi-drug-resistant microbial infections have we seen in New Zealand in the last year? How does this compare to earlier years or overseas cases?
"I’m not aware of any precise data on this (and the answer depends on how you define 'multi-drug resistant') but what is clear is that the incidence of invasive infections with gram-negative drug-resistant organisms of concern are becoming more frequently encountered, particularly in the hospital setting. I’m aware of several serious invasive infections over the last two years where colistin has been the only antibiotic with activity against the infecting bacteria.
"This sort of thing was virtually unheard of 5-6 years ago. Colistin is a relatively toxic antibiotic with unknown effectiveness for many types of infections. Colistin was largely abandoned in favour of less toxic agents during the 1970s but is now being used again purely out of necessity. What’s more, resistance to colistin is rapidly on the rise globally with resistance genes becoming more prevalent."
Which drug-resistant organisms are we most worried about in New Zealand?
"Carbapenemase-producing Enterobacteriaceae (CPE) are highly resistant forms of bacteria such as E. coli and closely related species that commonly cause a variety of infections in hospitalised patients (pneumonias, wound infections after surgery, urinary tract infections and so on). These organisms pose a particular risk to critically ill patients in the ICU setting and immune-compromised patients (for example patients undergoing treatment for cancer or solid organ transplants). Increasing prevalence of Carbapenemase-producing Enterobacteriaceae colonisation and incidence of infection in hospitalised patients is both a high likelihood and high impact threat to the safe delivery of complex, high tech healthcare, both in New Zealand and globally.
"There are other multi-drug resistant organisms of concern, but some are already endemic in New Zealand and the incidence of infection appears relatively stable (e.g. Methicillin-resistant Staphylococcus aureus - MRSA). Carbapenem-resistant Acinetobacter baumannii is another multi-drug resistant organism of concern, but the threat is primarily to patients in ICU settings and the main source of introduction is from patients directly transferred from overseas units (so the scope of the threat is far narrower than for Carbapenemase-producing Enterobacteriaceae and opportunities for control is higher)."
What are we doing to keep New Zealanders safe from drug-resistant microbes?
"The New Zealand Antimicrobial Resistance Action Plan is published on the Ministry of Health website, but unfortunately it has recently been amended to the effect that many of the original commitments have been softened or removed. Having said that, there is some excellent work being progressed by the Ministry of Health Communicable Disease Team, seeking to implement a national Surveillance and Response programme for Carbapenemase-producing Enterobacteriaceae that spans across the entire Health and Disability Sector.
"Increasingly programmes are developing locally in DHB hospitals to reduce unnecessary antibiotic use (antibiotic stewardship programmes). Public awareness campaigns are also progressing and slowly gaining momentum. Public awareness is important to reduce expectation for antibiotics when consumers present to their GPs with infections where antibiotics wouldn’t help."
Since the rise of antimicrobial resistance, researchers have been searching for new drugs to replace the once microbes are outsmarting. Do we have a new arsenal of drugs? What are the barriers or delays to developing new drugs?
"There has been some progress with gram-positive organisms such as MRSA (Ceftaroline, Linezolid, Daptomycin), yet relatively little for Carbapenemase-producing Enterobacteriaceae and little on the horizon. The focus therefore has to be on prevention through limiting transmission in healthcare facilities and reducing progression from colonisation to infection in those who are asymptomatic carriers.
"Reducing antibiotic use also creates an ecological environment that is less conducive for such organisms to spread and gain a foothold in the population (as a colonising organism). Barriers to creating new drugs are both commercial (antibiotics are not big money earners for drug companies compared to anticancer agents for example) and due to the biochemical challenges – for beta lactam type drugs for example (penicillin type antibiotics – probably the most effective and safe class of antibiotics), the chemical side chain possibilities have been extensively explored and it is getting increasingly challenging to discover new possibilities."
What can everyday Kiwis do to help the fight against superbugs?
"Understand that antibiotics are a valuable resource that essentially becomes less effective if used excessively. Not every infection requires antibiotics and it’s best to keep them in reserve for when there is a clear benefit. When going to the GP with an infection, have an open mind about whether antibiotics are needed or not and do not pressure your GP for a prescription. If given the option by your GP, avoid antibiotics and allow the immune system to do its work and the infection to run its course."
No conflict of interest.
Distinguished Professor Nigel French, Professor of Food Safety & Veterinary Public Health, comments:
Which organisms are we most worried about affecting New Zealand's animals?
"It’s not just organisms that affect New Zealand animals, but also ones that are carried by healthy animals that affect people. So these are some of the most important:
Bacteria carried by healthy animals that affect people:
• Campylobacter – a new strain of resistant Campylobacter has emerged in New Zealand over the last 5 years, known as Campylobacter jejuni ST6964. This has become widespread in the poultry industry and in people.
• Extended-spectrum beta lactamase producing E. coli – these can be found in healthy pets and livestock and are a cause of urinary tract infections in people.
Bacteria that cause disease almost exclusively in animals:
• Staphylococcus pseudintermedius. This causes skin and other problems in pets and multidrug-resistant strains have emerged in New Zealand.
Bacteria that cause disease in both people and animals:
• Resistant Staphylococcus aureus, and MRSA in particular."
How does this
compare to earlier years or overseas
"We have relatively low levels of resistance compared to other countries, but the increase in resistance in organism such as Campylobacter and Staphylococcus pseudintermedius is a concern."