Inspired by my trip to the Superbugs exhibition at London’s Science Museum, last week I wrote about the Rise of the Superbug and how they came to be. Obviously we want to do our best to prevent any more developing, but that still leaves us with the problem of what to do with the ones we already have, especially as no new antibiotics have been brought out for use in patients in the last 30 years. But could there ever be a Fall of the Superbug? What are scientists coming up with to tackle the problem of superbugs?
Well, this is where it starts to get really interesting. Scientists are really thinking outside the box, looking at the problem in new and different ways.
- Viruses which infect bacteria, destroying them
- Bacteriovores (the suffix –vore comes from the Latin vorare ‘to devour’; carnivores are meat eaters, Latin carnis ‘flesh’; herbivores are plant eaters, Latin herba ‘plant’; omnivores eat both meat and plants, Latin ‘omni-‘ meaning ‘all’; so what might bacteriovores be?)
- New ways of exploiting existing antibiotics
- Specially engineered proteins
We are all pretty familiar with viruses, bizarre things that they are. A lot of common illnesses in humans are caused by them – the common cold, for example. Viruses can kill people: HIV or Ebola, for example, or even some strains of flu. But what if you could infect bacteria with a virus which would kill them? They exist, they’re called bacteriophages, and they’re a global research focus. They are specific, so each particular type will only attack one single species of bacteria, however there are groups of scientists trying to genetically modify them to target other bacteria and particularly superbugs.
How does a virus (shown in green) kill a bacterium (shown in blue)? (Yes, I drew it myself. That goes for the next couple of pictures too. Now I just need to persuade the scanner that it (a) works, and (b) is friends with my computer…!)
Scientists have also discovered a predatory bacteria that hunts and effectively consumes other bacteria. (It was actually first observed by accident in 1962, but is now really coming into the spotlight.) It’s called Bdellovibrio Bacteriovorus, and studies have already shown it to be effective in treating some bacterial infections in animals. It is hoped that it will prove useful in treating skin and wound infections in particular – but a lot more investigation is needed before trials in humans can begin.
How does bdellovibrio bacteriovorus (shown in red) deal with bacteria (shown in blue)? Pretty similarly to viruses, actually!
Earlier this year, a team working at UCL discovered that the semi-synthetic antibiotic oritavancin (closely related to vancomycin, one of the ‘last resort’ antibiotics for superbugs such as MRSA) had some rather special and unusual properties. In order to work, antibiotics need to attach themselves to the bacterial cell surface, a bit like a key into a lock. One of the ways bacteria become resistant to antibiotics is through slight changes at the molecular level on the cell surface – like they have changed the locks. What the team at UCL discovered though, is that oritavancin can use ‘brute force’ to break through anyway, tearing holes in the cell walls and killing the bacteria. Oritavancin also forms clusters, and when these clusters dig into the cell surface they actually push each other apart, tearing the cell apart with them. It’s a new way for antibiotics to work, and one which has a lot of potential.
SNAPPs (Structurally Nanoengineered Antimicrobial Peptide Polymers – cool acronym!) are star-shaped proteins which kill bacteria, developed last year (2016) by a group at the University of Melbourne in Australia. SNAPPs are entirely synthetic, and were inspired by the proteins produced naturally within our bodies to help fight infection. They have already shown themselves to be effective against superbugs in tests using mice, but are still a long way of trials in humans, although it is thought they are non-toxic. They might be able to replace antibiotics in the future.
I find the way SNAPPs work quite clever. It’s ingenius, really.
Other problems in the fight against superbugs are to do with how they spread, particularly in hospitals, and in pre-emptive treatment of potential infections. There’s some cool science going on here too.
Hospitals see an awful lot of people in a week, even more across a year. They need to do everything they can to minimise the risk of infections spreading between patients, sterilising wards and rooms, washing their hands at every possible opportunity, and doing everything they can to make sure nothing spreads. Scientists and inventors are coming up with some clever things to deal with this.
One of the easiest ways for infection to spread is through hospital equipment. So, new equipment is being designed which is easier to clean (all rounded corners, with no cracks and crevices for things to get caught in – and also physically safer for patients, especially the elderly). It even has keyless-entry, so there isn’t a keyhole for bacteria to build up in and doctors aren’t constantly having to handle keys to gain access.
Some metals, notably copper and silver, can naturally break down the cell walls of bacteria and kill them. Making equipment that doctors touch regularly and around a lot of different people (such as pens and stethoscopes) out of copper rather than other metals is quite expensive, but is very effective in minimising the spread of bacteria. And of course, the less bacteria is able to spread, the fewer people will become infected, and the lower the need for antibiotics to treat these infections.
Look at all the things made of metal that this doctor uses every day, and think about the number of bacteria that could collect on each surface. Now imagine if all that metal was copper – how many bacteria could it kill?!
Then we come to the rooms themselves. UV light can break down bacterial DNA, killing them (obviously!). Compared to a standard disinfectant cleaner, it can kill up to 70% more bacteria in a hospital room – pretty impressive! – and could sanitise an entire room in 10 minutes. Could you scrub that fast?! As an added bonus, it can also sterilise the air and ceiling!
A big use of antibiotics in hospitals is in treating extensive skin wounds, most often burns. Although these patients may not have an infection on arrival in hospital, they are still treated with antibiotics just in case, as the potential risk of them contracting an infection is quite high. This pre-emptive use of antibiotics is really quite unnecessary though – why treat something which isn’t there and may never be there? So a team of scientists has come up with a pretty awesome idea: bandages which glow if there is a bacterial infection. All patients with these sorts of major skin wounds are wrapped up in bandages while they heal. A bandage which glows if and when it detects a bacterial infection can alert doctors to a need for antibiotics to be prescribed, and so they are only taken by patients who actually need them.
What do you think? How can we cause the Fall of the Superbug, and what will your contribution be?
In the classroom:
Infection and disease is obviously a sizeable part of any Biology GCSE, and antibiotic resistance is featuring increasingly as well. (Did you know, for example, that gonorrhoea is on the verge of becoming a superbug?) It is also something which students may have personal experience of through family members. (I myself lost a relative while I was at school to hospital-contracted MRSA.) There are opportunities in this for looking at how scientists approach problems (what do you do when you can’t just find new antibiotics), and for discussions on the ethics side of medical research. You could ask students about the steps they think a new drug should go through before being released for use in humans, and discuss differing views on animal testing (a critical stage for all drugs to go through before being approved for trials in humans). Allowing students to come up with ideas on this in the context of antibiotic resistance and the need for a fast solution, and then extending the discussion to thalidomide and giving them the opportunity to consider whether their view changes in light of new information would also be brilliant for covering a number of the working scientifically specification points, as well as preparing them for future scientific study, and developing in them a deeper understanding of the complexities of the ethics of research. I’d be interested to hear the ideas your students come up with! There are excellent opportunities for both research and design homeworks, and inter-student competitions too.