Don’t let the superbugs bite

But don't despair - we might be struggling but we are not beaten yet.

Evolution continues to be a bitch. Recently scientists gathered in Kensington, London, to have a good moan and to plan what can be done about it. “Superbugs and Superdrugs” is a great title for a meeting. Unfortunately the bugs seem to be more super than the drugs.

While that meeting went on, the US Centres for Disease Control and Prevention (CDC) issued a warning that we are entering a “nightmare” era. The CDC’s problem is a killer bacterium known as CRE, which is spreading in the US. Some strains of CRE are not only resistant to all antibiotics; they are also passing on that resistance to other bacteria, creating drug-resistant strains of E coli, for instance. On 11 March, Sally Davies, the UK government’s chief medical officer, asked the government to add the superbug problem to its “strategic risk register”, which highlights potentially catastrophic threats to the UK.

For a while, it all looked so good. When scientists discovered penicillin, then ever more weapons for our antibiotic arsenal, it seemed that bacteria had been defeated. The problem is, they fought back.

For all the worry over CRE, perhaps nowhere is this antibiotic resistance more evident than with tuberculosis. In the west, we won the war on TB so convincingly that receiving the BCG vaccine against it – once a waymark in British childhood – is no longer routine. Only in certain inner-city communities where migrant populations increase the likelihood of encountering the TB bacterium are children routinely immunised. However, in 2011, the World Health Organisation marked London out as the city with the highest TB infection rate in western Europe.

Many resistant bacteria originate in hospitals, where pharmaceutical regimes kill off the normal strains, making space in which bacteria that are naturally resistant can proliferate. Yet you can’t always blame the drugs. Research published at the end of February shows that drug resistance can arise even when the bacteria have never encountered a chemical meant to kill them.

In the study, E coli bacteria were made to suffer by exposing them to heat and restricting the nutrients in their environment. According to conventional wisdom, this should have kept proliferation in check – but it caused a spontaneous mutation that made the E coli resistant to rifampicin, one of the weapons in our antibiotic arsenal. What is worse is the observation that there was good reason for this mutation to arise: it made the stressful conditions more survivable. Bacteria with the mutation grew much faster.

Bacteria are survivors – if they can’t magic up a spontaneous mutation, they’ll pick one up in the street. A sampling of puddles in New Delhi showed that almost a third contain the genetic material that allows bacteria to produce an enzyme that destroys a swath of antibiotics. The NDM-1 gene is particularly evil. Its tricks include forcing itself into gut bacteria such as E coli that are incorporated into faeces; as a result, the resistant strains travel between hosts with ease.

Many infections involving a bacterium carrying NDM-1 are untreatable. GlaxoSmithKline is reportedly developing a drug to deal with it but it is years behind the curve. In the autumn, an EU project to mine the seabed for so far undiscovered antibiotics will start up, but it will take years for that, too, to bear fruit.

Let’s end on a positive note. Superbugs might be evolving in fiendish ways but they’re doing it blind and they’re up against evolution’s greatest invention – the human brain. We might be struggling but we are not beaten yet.

The EHEC bacteria. Image: Getty Images

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 25 March 2013 issue of the New Statesman, After God

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Fanging out: why do vampire bats groom each other so often?

New research shows social grooming and food sharing are more common adaptive traits in vampire bats than other species.

A new study has shown social grooming behaviour is more prevalent in vampire bat species than their non-parasitic variants. The researchers used the species Desmodus rotundus and found that the bats spent 1.5-6.3 per cent of their time engaged in social grooming, compared with just 0.5 per cent in other species.

It's not exactly a secret that a range of animals engage in social interactions. This includes hyenas who simply greet each other to increase cooperation. However, recent studies have focussed on the use of social grooming being used by animals to maintain stable relationships.  

For example, age and body weight have been linked to the amount of social grooming given by dairy cows, and licking and head rubbing are used by lions to create bonds between individuals. Vampire bats also protect each other against bats with no social links to a group. Each roost site usually contains 8-12 female adults and their offspring, defended on the outside by an adult male.

Vampire bats not only show social grooming through the cleaning of each others' bodies, but also by sharing food through the ever-appetising regurgitation process. However, both of these behaviours are directly linked to one another.

When a pair of vampire bats are grooming each other and cleaning each other's bodies, they assess the bulging size of the abdomen. This allows them to check if their partner has eaten, and whether they need to regurgitate and share food.

Sharing food is a vital part of feeding and cooperation in vampire bats, as almost 20 per cent of bats don't find any food each night. This starts a ticking clock, as most bats can starve to death in under 72 hours.

The importance of social bonding is reflected in the anatomy of the bat. In proportion to their relatively small body size, vampire bats have a very large brain and neocortex. Previous studies have shown the size of the neocortex is linked to more complex social behaviour and bonding.

The authors of the paper conclude that social grooming acts as a way for bats to display their hunger to partners, or alternatively, that they are willing to share food, and for the need to sustain close bonds.