Categories: Applied Chemistry , News , Policy | 1 Comment
There’s no doubt that the evolution of drug-resistant antibacterial is a worrying trend. Methicillin-resistant Staphylococcus aureus (MRSA) may have taken most of the headlines, but while we’ve been discussing how best to wash our hands in hospital wards, other, more insidious resistant bacteria have come to the fore.
In March, Sally Davies, the UK’s Chief Medical Officer described antimicrobial resistance as posing a ‘catastrophic threat’. And recently, Tom Frieden, Director of the US Centres of Disease Control and Prevention (CDC), warned ‘If we are not careful, we will soon be in a post-antibiotic era … and for some patients and for some microbes, we are already there.’
This month saw the publication of a two key reports: the UK five year antimicrobial resistance strategy 2013 to 2018 published by the Department of Health and Department for Environment, Food and Rural Affairs; and the CDC tome Antibiotic resistance threats in the United States, 2013. In a little over 140 pages between them they scan the landscape, identifying and, for the first time, classifying the threats posed by antibiotic resistant bacteria.
Being in the UK, my understanding of antibiotic resistance has been based mainly on the British narrative – the rise of MRSA in hospitals (despite being first identified in the 1960s), over-hyped panic headlines about ‘superbugs’, followed by the discovery of ‘hospital acquired’ MRSA in the community. Simultaneously, the newspapers have charted the rise in cases of clostridium difficile (c. dif.) infection which, although not particularly resistant to drugs, are a result of antibiotic use (or arguably overuse). As a science journalist, I’ve been more concerned about the rise of drug resistant tuberculosis. The cases are relatively rare, so there has been little in the mainstream press, but we in the UK are only a generation or two away from a time when TB was rife, and these disturbing cases are now on the rise.
Bacteria are indifferent to geopolitical boundaries, a fact which the UK report acknowledges by calling for greater collaboration with the World Health Organisation and the World Organisation for Animal Health. Looking at the situation in the US, the report states that over 2 million people are infected with antibiotic resistant bacteria each year, leading to over 23,000 deaths. A further 250,000 acquire an infection of c. dif., and more than 14,000 of those don’t survive. The problem is not limited to the US and UK, of course – research shows resistance all over the world.
Both reports are available for free online, though the CDC’s seems better targeted at a public audience. It focusses just on concerns around bacteria (well, okay, they slip one fungus in too). Resistant viruses and parasites are out of their scope for now, though undoubtedly there will be shared lessons. In the report, the CDC stratifies bacteria by how significant the thread is perceived to be.
‘Urgent’ threats (defined as ‘high-consequence … threats because of significant risks identified across several criteria’) include the aforementioned c. dif, but also carbapenem-resistant Enterobacteriaceae (CRE) and drug-resistant Neisseria gonorrhoeae. CREs are a particular concern to people receiving hospital treatment – catheters and ventilators are both risk factors for infection. Neisseria gonorrhoeae, as the name suggests, is the organism behind the sexually transmitted infection gonorrhoea.
The next category represents the ‘serious’ threats, and contains a raft of familiar infections: pseudomonas, salmonella, shigella, MRSA and TB. Threats were categorised as ‘serious’ if there was evidence of a decline in incidence, or if other therapeutic agents were available.
Finally, vancomycin-resistant Staphylococcus aureus (VRSA), erythromycin-resistant Streptococcus Group A and clindamycin-resistant Streptococcus Group B were categorised as ‘concerning’: ‘bacteria for which the threat of antibiotic resistance is low, and/or there are multiple therapeutic options for resistant infections.’
The stratification may give us a robust guide to our priorities, but cannot in itself tell us what we need to do. The report (as is often the case) calls for more research, but also sets out four core actions:
- Avoiding infection in people and animals (as antibiotic use in animals also fosters resistance)
- Tracking and collecting better data
- Improving antibiotic stewardship and education around the prescription of antibiotics
- Developing new drugs and diagnostic techniques
The UK report sets its targets a bit wider, including resistance to antivirals and antifungals. The aims and objectives set out are broadly similar to those of the CDC, but with more specific commitments, including the earmarking of up to £4 million to set up a new, dedicated, National Institute of Health Research (NIHR) Health Protection Research Unit. This is promising, but doesn’t make up for the fact that the UK underinvests in antimicrobial resistance research, according to a study in the Journal of Antimicrobial Chemotherapy, also published this month.
Research in the chemical sciences will be key to achieving these aims. A quick search on the Chemistry World website can give us a snapshot of the amount and breadth of work taking place:
- Ben Feringa’s recently published work on ‘switchable’ antibiotics could develop a class of drug that is only active while in the patient
- A colourimetric array developed in Taiwan can help to identify bacteria quickly, cutting the need for broad-spectrum antibiotics
- Recent work in Oxford could lead to drugs that weaken bacterial defences, reducing the need for long courses of antibiotic treatment
- A range of compounds, including a peptide from wasp venom, are being investigated with aim to keep catheters and medical devices sterile
There are further bright lights on the horizon. Only very recently has it become a realistic proposition that we will be able to sequence the genome of the bacteria causing an infection in emergency rooms and local GPs. The technology and the software needed to understand the results have been getting cheaper and easier to use every year. Soon every infection will be able to be sequenced, providing enormous amounts of information on the spread, evolution and vulnerabilities of the bacteria involved.
Hopefully, today’s research and that funded and supported by the new strategy will keep us from the ‘post-antibiotic era’ Frieden predicts – but only if we act globally to get antimicrobial resistance under control.
Want to know more?
The Royal Society of Chemistry is hosting a panel discussion entitled ‘Beating the Superbugs: avoiding an antibiotic apocalypse’ in London on the 18th November – find out how you can join in here: http://rsc.li/superbugs