The threats of antibiotic resistant superbugs to New Zealand

By Siouxsie Wiles 26/09/2014 1

In this week’s New Zealand Medical Journal is a paper by Deborah Williamson and Helen Heffernan on antimicrobial resistance in New Zealand (1). This comes hot on the heels of the WHO report which gave a global picture of antibiotic resistance (2), and highlights what the big challenges are for New Zealand.

So what are the antibiotic resistant superbugs that pose a risk to the health of New Zealanders?

According to the authors, there are four main superbugs we need to be watching:
1. Methicillin Resistant Staphylococcus aureus also known as MRSA
2. Extended-spectrum B lactamase (ESBL) producing Enterobacteriaceae, especially E. coli and Klebsiella pneumonia
3. Mycobacterium tuberculosis which causes the lung diseases tuberculosis (TB)
4. Neisseria gonorrhoeae which causes gonorrhoea

What are the key factors driving antibiotic resistance in New Zealand?

The authors highlight three main drivers which they believe are contributing to the problem:
1. The use and overuse of antibiotics in people and animals
2. Transmission of antibiotic resistant microbes in both the community and within healthcare facilities, including rest homes
3. Increasing globalisation – we are importing many of our antibiotic resistant superbugs from abroad

MRSA – a problem of our own making

Over the last few years there has been a huge increase in the number of skin and soft tissue infections caused by S. aureus in New Zealand. Alongside this, there has been a huge increase in prescriptions for a topical antibiotic called fusidic acid. As a consequence, one of the major clones of S. aureus now causing disease in New Zealand is an MRSA clone called AK3 which is resistant to fusidic acid (3).

Importation of resistant superbugs

Some of the superbugs of worry, notably extremely resistant strains of E. coli, K. pneumonia and M. tuberculosis are mainly being imported into New Zealand from countries like India, China and those in south-east Asia. This is going to be an area to watch, especially given the importance of countries like China for trade and tourism in New Zealand.

Gonorrhoea – the tip of the iceburg for sexually transmitted diseases

In New Zealand, sexually transmitted infections (with the exception of HIV) are not notifiable. This means that the data we have on these diseases is based on the voluntary provision of the numbers of diagnosed cases from laboratories and sexual health and family planning clinics. What’s crucial to this is that many people can have no symptoms, hiding the true burden of disease. Gonorrhoea is one of these. While most men will have symptoms when they have the disease, half of women can be asymptomatic. Importantly, untreated infection can lead to infertility in women.

In 2013 there were 3,334 cases of gonorrhoea in New Zealand (4). What is shocking is that 1,145 of these cases were in young people under the age of 19. In fact, there has been a 43% increase in the rate of gonorrhoea in 15–19 year old women between 2009 and 2013. Less than half of sexually active young people report using condoms (5) which goes some way to explaining why our rates are rising. If we end up with a completely untreatable strain of N. gonorrhoeae taking hold in New Zealand this could have a huge impact on our future fertility.

1. Williamson DA & Heffernan H (2014). The changing landscape of antibiotic resistance in New Zealand. New Zealand Medical Journal.
2. World Health Organisation (2014). Antimicrobial resistance: global report on surveillance 2014. ISBN: 978 92 4 156474 8.
3. Williamson DA et al (2014). High Usage of Topical Fusidic Acid and Rapid Clonal Expansion of Fusidic Acid-Resistant Staphylococcus aureus: A Cautionary Tale. Clin Infect Dis. pii: ciu658.
4. Sexually transmitted infections in New Zealand 2013. Institute of Environmental Science and Research Limited.
5. Clark TC et al (2013). Youth’12 Overview: The health and wellbeing of New Zealand secondary school students in 2012. Auckland, New Zealand: The University of Auckland.

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