06:34am Monday 25 September 2017

A bacterial "anti-glue" to fight infections

When under threat, bacteria shield themselves in a slimy protective barrier. This slimy layer – known as biofilm – can protect the bacteria from antibiotics, to a scrubbing brush and bleach.

In the home, this leads to bacteria resisting household cleaning products leading to contaminated kitchen and bathroom surfaces.

More importantly in healthcare, biofilms can lead to life threatening and difficult to treat infections, particularly on medical implants such as heart valves, artificial hips and even breast implants.

Now a team led by Newcastle University’s Professor Grant Burgess, have shown for the first time that not only do these tiny microbes cover themselves in a slimy biofilm “armour” but they can also remove their own biofilm once it is no longer needed.

Using DNA as a “kind of reversible glue”, the bacteria protect themselves from danger by producing a web of DNA which holds the cells together and sticks them to a surface, thereby shielding the microbes from harm. However, when the bacteria want to move to pastures new, they release an “anti-glue” – an enzyme – which chops up the DNA web, removing the biofilm and releasing the bacteria from its grip.

Publishing their findings in the academic journal PLoS ONE, the team, which includes Utrecht based microbiologist Dr Reindert Nijland and Newcastle chemist Dr Michael Hall, said that understanding how bacteria use enzymes to break down the biofilms is the key to removing slime in the home, in industrial settings and fighting bacterial infections.

Professor Grant Burgess, explained: “When this glue is released, the long strands of DNA stick the cells together and to surfaces, a bit like a Spiderman’s web. But when the cells want to escape and move on from that protection they release an “anti- glue” which chops up the DNA releasing the cells.  It’s an amazing phenomenon, and if we can harness this enzyme and use it to our advantage, to get rid of unwanted biofilms, then it could prove a vital tool in our fight against infection.”

As part of this latest research the Newcastle team studied the marine bacterium Bacillus licheniformis and found that it releases a nuclease enzyme to break down the biofilm. When the enzyme was purified and added to other biofilms it quickly dissolved the slime exposing the bacterial cells and leaving them vulnerable.

Professor Burgess added: “If we can extract or develop this enzyme then we can turn the bacteria back on themselves for our own benefit. Scientists used this approach with penicillin when they took a microbial antibiotic and purified it for Man’s own use, to kill bacteria when and where needed. We want to do the same with this enzyme.”


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