The emergence of a new ‘superbug’ in China has led to apocalyptic talk of our having finally entered the post-antibiotic era – where common bacteria are resistant to every antibiotic we have available in the cupboard to chuck at them.
Should we be concerned? The discovery of bacteria that are resistant to Colistin, an antibiotic of ‘last resort’ is certainly not the best news but that’s not the worrying part. This particular antibiotic (aka polymixin E) was first approved in the late 1950s for the treatment of acute and chronic infections caused by resistant bacteria. Its use was discontinued in the 1970s due to its toxicity, but it has been wheeled out of retirement for infections that prove resistant to everything else.
Resistance to antibiotics is not new, indeed there were penicillin-resistant bugs long before we discovered penicillin and the war between our microbial overlords and what we could find to chuck at them has been escalating ever since. Many predicted MRSA would be the first ‘pan-resistant’ bug but it was beaten to that dubious accolade by gonorrhoea last year; now about 10% of cases of the clap are untreatable.
Here’s the worrying bit. The difference here is the mechanism of resistance. Bacteria have genes just as we do, and if one of them mutates to be able to resist – say – penicillin, its daught ears will share that same trait. But this time the resistance is carried on a ‘plasmid’: essentially a packet of genetic material that bacteria of different species can swap and share amongst each other, rather like football cards.
So it’s just not the one ‘superbug’, it’s the potential for many different species of bacteria to share this same trait amongst themselves.
Disturbingly, this plasmid moves easily between common human pathogens such as E. coli, Klebsiella and Pseudomonas which cause a large proportion of the blood, urinary and gut infections already responsible for tens of thousands of deaths each year. We have seen this type of plasmid-mediated resistance before and it’s not pretty.
But the fact Colistin is critically important for human health hasn’t stopped farmers across the world using it in profligate quantities, not as an antibiotic but to fatten up livestock. Especially in China. You can find traces of it in the soil and in water courses as well as in the food chain, so discovering resistance in bacteria that infect humans is hardly surprising.
And as long as farmers put antibiotics used to fight human infections into animal feed this situation is unlikely to improve.
So what’s to be done? As common infections become ever more difficult to treat with antibiotics we need to do all we can to prevent their transmission in the first place but we also need some new approaches.
My money is on phage therapy. This is where you get viruses to target the bacteria you want to get rid of. It was used behind the iron curtain for years and is both very specific and very effective. Phages are everywhere – you’ll find half-a-billion in a teaspoon of seawater – and their therapeutic use started during the First World War thanks to a physician called Félix d’Herelle. He developed phage-based treatments sold by a company we now know as l’Oréal.
Phage therapy went out of vogue in the 1940s with the advent of modern antibiotics. People found the idea of ingesting bacteriophages icky – despite the fact we ingest hundreds of them every time we lick our lips.
And it’s ‘phaaayge‘ as in ‘page’, not ‘pharge‘ as in ‘large’. Unless you’re French. Or pretentious. Or possibly both.