Bacteria Wars: the scientist strikes back

By Kruti Shrotri

Bacterial infections are becoming a serious threat to society as the bacteria that cause them become increasingly resistant to our current antibiotics. Earlier this year, Chief Medical Officer, Professor Dame Sally Davies, warned that within twenty years even minor surgeries may lead to death through untreatable infections. However, many researchers are developing novel ways of treating infections, offering more hope in tackling the problem.

Antibiotics work by disrupting the internal processes that bacteria use to survive or reproduce, thus killing them or preventing them from spreading. However, bacteria can mutate into new strains that resist even our most powerful antibiotics. Developing new, more potent antibiotics is one way of addressing the problem, but this leaves open the possibility that bacteria will grow resistant to these new antibiotics too.

MRSAEngineers at MIT have been exploring new ways of fighting resistant bacteria. The team, led by Timothy Lu, have been using a genome editing system called CRISPR. This system, developed over a decade ago, can disable individual targeted genes.

Lu and his colleagues have found they can use CRISPR to selectively kill bacteria based on their genes. This includes bacteria carrying genes that make them resistant to antibiotics or that make them cause disease. The researchers have now begun testing their new methods in mice, with the hope that the technology will eventually be adapted to treat bacterial infections in humans.

Another novel approach to fighting bacterial infections uses “quorum sensing”: a method used by many bacteria to communicate with each other via chemical signals. One single bacterium attacking a human host does not cause an infection; but using activation signals, millions of bacteria synchronise their attacks, rendering them potent. However, if these signals can be blocked, the bacteria will no longer be able to synchronise their behaviour, reducing the harm they cause.

Professor Helen Blackwell at the University of Wisconsin-Madison has been experimenting with artificial compounds that mimic quorum sensing. Not only has she created some compounds in which the activation signal was blocked, but, by making minor tweaks to compounds, she was able to convert an activation signal into an inhibition signal, and vice versa.

Blackwell says that these findings may “help us design new compounds to inhibit quorum sensing and reduce the harm of bacterial infections, without causing the drug resistance that is producing so many problems today”.

These are just some of the advances being made that might be crucial to tackling one of the greatest problems of our time.

Image: ‘Methicillin-Resistant Staphylococcus aureus (MRSA) Bacteria by NIAID under creative commons license