Posts Tagged Superbugs

Will new antibiotic Teixobactin save us all? Umm, not quite. Siouxsie Wiles Jan 08



Researchers in Germany and the USA have just published a paper in the journal Nature describing a new antibiotic they have called Teixobactin (1). This study is good news; the World Health Organization warned last year that cancer chemotherapy and routine surgery will soon become life-threateningly risky because of the worldwide rise in antibiotic-resistant superbugs (2). So will Teixobactin save us all from a post-antibiotic era? Maybe, but not in the way you think it might. Here’s a little FAQ.

1. What is Teixobactin?

Teixobactin is a newly discovered antibiotic produced by a previously uncultured soil bacterium called Eleftheria terrae. Teixobactin acts by stopping some bacteria from making their cell wall (their outer coating, if you like). It was found to be active against a range of nasty bacteria, including Staphylococcus aureus (also known as MRSA), Clostridium difficile (which causes nasty diarrhoea which can be deadly in elderly people), Bacillus anthracis (which causes anthrax) and Mycobacterium tuberculosis (the cause of TB). This is good news as we have a desperate need for new antibiotics against these superbugs. The researchers also showed that Teixobactin did not have any effect on mammalian cells and could protect mice infected with S. aureus and Streptococcus pneumoniae. This is also good news but it will still take 2-5 years more testing before Teixobactin makes it to a doctors surgery or hospital near you.

2. So why isn’t Teixobactin going to save us all?

Because bacteria roughly divide into two groups based on their cell walls; they are either classified as Gram-positive or Gram-negative*. Teixobactin only works against Gram-positive bacteria. Unfortunately, it can’t get around the extra outer membrane of Gram-negative bacteria. This means the antibiotic doesn’t work against some pretty nasty bacteria that we are running out of antibiotics to kill, like E. coli, Pseudomonas aeruginosa and Klebsiella.

3. Finding new antibiotics – the iChip.

How the researchers discovered Teixobactin is in some ways more important than the antibiotic itself. Many microbes remain undiscovered, partly because it has been impossible to culture them in the laboratory. Given that antibiotics are made by microbes, this means that many antibiotics lie undiscovered all around us.

The researchers made a sort of ‘hotel’ for soil bacteria, that allowed them to cultivate previously uncultivated bacteria. This ‘hotel’ is called the iChip and is basically a board with holes on it. Each whole was seeded with a single bacteria from a sample of soil, and then the whole board, covered in a permeable membrane, was dunked in to a beaker of soil so the bacteria could access all the nutrients they needed to grown. Very clever. The discovery of Teixobactin should be just the tip of the antibiotic iceberg.

4. Is Teixobactin really resistant to resistance?

One of the interesting findings of the study was that the researchers couldn’t produce strains of M. tuberculosis or S. aureus that became resistant to Teixobactin. I think it’s a little premature to suggest that bacteria are unlikely to become resistant to Teixobactin based on the published data; the researchers didn’t try particularly hard to make it happen.

As Dr Prof. Ian Malcolm says: “Life finds a way”….

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*depending on whether or not they can be stained using crystal violet, a method known as Gram-staining.

1. Ling et al (2015). A new antibiotic kills pathogens without detectable resistance. Nature. doi:10.1038/nature14098
2. World Health Organisation (2014). Antimicrobial resistance: global report on surveillance 2014. ISBN: 978 92 4 156474 8.

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Life as we know it could end in ten years if we don’t start taking drastic action

The antibiotic resistant superbugs threatening New Zealand

The threats of antibiotic resistant superbugs to New Zealand Siouxsie Wiles Sep 26

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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.

Life as we know it could end in ten years if we don’t start taking drastic action Siouxsie Wiles May 01


Life as we know it could end in ten years if we don’t start taking drastic action. This is the message to come out of a new report by the World Health Organisation (WHO), their first look at antibiotic resistance around the world. The report finds that antibiotic resistant superbugs are present in every region of the world and that many countries lack even the basic systems to track and monitor them. It also highlights that microbes responsible for gonorrhoea, urinary tract infections, pneumonia, bloodstream infections, infections in newborns and intensive-care unit patients are now resistant to the most effective antibiotics used to kill them.

“Without urgent, coordinated action by many stakeholders, the world is headed for a post-antibiotic era, in which common infections and minor injuries which have been treatable for decades can once again kill,” says Dr Keiji Fukuda, WHO’s Assistant Director-General for Health Security.

Alongside vaccines, antibiotics are arguably one of the most important discoveries in medical history. In antibiotics, humans are exploiting the weapons produced as part of an arms race that has existed between microbes for millennia. The first antibiotic was used to treat people in 1937 and not long after that we became aware of the other side of the microbial arms race – that microbes can become resistant to these wonder drugs. Resistance to penicillin was known before the antibiotic even came into use.

Latest estimates put the number of potential antibiotic resistance genes that exist at more than 20,000. But it doesn’t end there, microbes have crafty ways in which they can share resistance genes among themselves, and this has exacerbated the problem. It’s not just a case of each species of bacteria having to develop its own resistance mechanism each time they come into contact with an antibiotic. Instead, different species of bacteria can share the genes with each other.

The fact that antibiotics have been is use for over 80 years, and it is only now that the WHO have produced their first global report on the state of antibiotic resistance, shows just how much we underestimated the impact antibiotic resistance would have. The report highlights what microbiologists have been shouting for a while now, that a world without antibiotics is a scary place, and we are likely to be living in that world in as little as ten years.

The report has a clear call for action on a number of fronts. It urges individuals to only take antibiotics when necessary and to complete their course. It urges health workers and pharmacists to do all they can to prevent infection and to prescribe the right antibiotics only when they are really needed. It also urges policymakers to regulate and promote the appropriate use of antibiotics in medicine, veterinary practice and agriculture.

In addition to these measures, it is clear that we also need new antibiotics, more vaccines and novel ways to tackle infectious microbes and the WHO placed fostering research and developing new tools as a way that policymakers and industry can help. Earlier this year, the UK held a parliamentary review of antibiotic resistance and President Obama recently announced he was committing $30 million annually for the next five years to detect and prevent infections in the USA.

So what is New Zealand’s government doing? Apart from trying to tackle the country’s shocking rates of rheumatic fever, not a huge amount. The recent inter-institutional application to set up an infectious diseases Centre of Research Excellence (CoRE) didn’t make the shortlist and infectious diseases were specifically excluded from the three health-related National Science Challenges announced by the government last year. In a country with increasing rates of infectious diseases, if tackling these aren’t a national challenge, then I don’t know what is.

UPDATE: There’s been a fair bit of media interest in this story. If you are interested you can see a clip of me talking about the issue on NZ breakfast TV here. Some people seem to have taken the call for us to develop novel ways to kill microbes as a sign we should be investigating complementary/alternative ‘medicines’. In fact, after I appeared on TV I was sent a tweet sending me to psychosomatic healing website. Let me be clear, we need new antibiotics, vaccines and innovative strategies to stay ahead of this apocalypse, not hand waving, magic water and the like.

When I wrote the post, the WHO report was still under embargo so I couldn’t link to it. You can now read it here. They have also made a handy infographic: infographic-antimicrobial-resistance-20140430

Monday Micro Siouxsie Wiles Dec 03

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Welcome back to Monday Micro. Last week’s Monday was lacking in microbiology factoids as I was at the New Zealand Microbiology Society‘s annual meeting*. This year it was at the University of Otago in Dunedin. Highlights for me were keynotes by Rob Knight (microbiomes and Next Gen Sequencing), Eric Ruben (TB) and Steven Wilhelm (cyanobacterial blooms). Tweets of some of the talks are here.

Highlights for me:

Finding that lots of people flush public toilets with their feet, that cyanobacteria are a bad food source “like ordering pizza and only eating the box”** and that “we are all accidents of history”***.

Moving on, Round 3 of the SciFund Challenge is in full swing so if you fancy supporting some microbiology projects Amy Truitt wants so study butterflies and their sexually transmitted diseases, Will Helenbrook is studying the effects of infectious diseases on Mantled howler monkeys and Andy MacDonald is working on Lyme disease.

* The slides for my talk (Fireflies and superbugs: when science and nature collide) are up on slideshare. I started my talk with my Meet the Lampyridae animation….

** Steven Wilhelm
*** Unknown kilted MC of conference dinner :)

From fireflies to superbugs…. Siouxsie Wiles Dec 08


I’ve spent the last few months working with a fantastic Australian animator, Luke Harris, and his team to tell the story of what I do and why in under 3 minutes. So if you want to find out a little more about the amazing beetle that is the firefly and how it is helping scientists battle against some of the world’s nastiest microbes then take a look.

Update 10/12/11: I was recently interviewed for Radio New Zealand’s weekly science show Our Changing World which aired on 8/12/11 so a longer explanation of my research without the amazing graphics can be found here.

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