By Siouxsie Wiles 28/05/2016


Antibiotic-resistant superbugs are in the news again. This time a strain of E. coli resistant to the antibiotic colistin has been spotted in the USA. So why is this newsworthy and should we be scared? 

A strain of E. coli has been identified in the USA that is resistant to the antibiotic colistin. A paper describing the strain has just been published in the journal Antimicrobial Agents and Chemotherapy (1). Colistin was discovered over 50 years ago but fell out of favour because it can damage a patient’s kidneys. Now it’s used as the antibiotic of last resort for treating infections caused by antibiotic-resistant strains of E. coli. This patient was lucky; the strain they were infected with was still able to killed by one last class of antibiotics so the patient was able to be treated. But it is just one step away from being untreatable.

While not used much in humans, colistin is used on agriculture, and in 2015 a gene for resistance to colistin was discovered in bacteria taken from animals, meat products and humans in China (2). This wasn’t the first time that resistance to colistin had been found, but this was the first time it had been discovered in a form that can easily move between different species of bacteria. Since then, its also been found in other countries in Asia, as well as in Europe, Canada, South Africa and South America.

What’s interesting about the case in the USA, is that the patient hadn’t travelled anywhere recently, suggesting that they picked up the resistant superbug in the USA. This would mean the colistin resistance gene is already present in the USA and likely being shared between different bacteria. The question now is where and how widespread is it? This is one of the problems with resistant superbugs – many people carry them in their bowels or up their noses, without any symptoms, and can move them from country to country when they travel. Its only a matter of time before such a superbug to find its way here, if it’s not here already.

Antibiotic-resistant superbugs set to kill more people than cancer, and cost the world’s economy trillions

In a series of reports commissioned by the UK’s Prime Minister David Cameron, economist Sir Jim O’Neill has estimated that without urgent action, antimicrobial resistance will kill 10 million people a year by 2050, more than will die from cancer. This is because antibiotics are crucial for many medical procedures, used to prevent infection in vulnerable patients. Without antibiotics, procedures like caesarean sections, joint replacements and chemotherapy for cancer, will become too dangerous to perform. “The end of modern medicine as we know it…” is how Margaret Chan, director-general of the World Health Organization (WHO), described the issue  back in 2014 when the WHO released their first global report on the topic.

O’Neill has also put an economic cost on antimicrobial resistance, estimating that inaction will cost the world’s economy 100 trillion USD by 2050. In his latest report [pdf here], O’Neill puts forward a number of recommendations, which he describes as “extremely good value for money”. His message is clear. We need global action to raise awareness of antimicrobial resistance, and all governments need to be looking at how their countries use antibiotics, not just in human and animal health, but also in agriculture, where they are used as growth promoters and to allow animals to be factory farmed. O’Neill is also calling on governments to incentivise and fund the development of new antibiotics and diagnostic tools for infectious diseases.

Could new antibiotics be discovered right here in NZ?!

With support from Cure Kids, my lab is doing its bit to search for new antibiotics. We are collaborating with fungi expert Bevan Weir at Landcare Research, using superbugs we have engineered to glow, to screen a freezer-full of New Zealand fungi to see if they produce antibiotics. Check out the short video below for more details. If you want to help us out, then you can sponsor a fungi or buy a t-shirt or mug made from our amazing glowing sci-art pieces.

 

References:

  1. McGann et al (2016). Escherichia coli harboring mcr-1 and blaCTX-M on a novel IncF plasmid: first report of mcr-1 in the USA. Antimicrob. Agents Chemother. doi:10.1128/AAC.01103-16
  2. Liu et al (2016). Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in 85 animals and human beings in China: a microbiological and molecular biological study. The Lancet. Infectious diseases 16:161-168.

 


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