Ithree Institute, University of Technology Sydney, Sydney, Australia

Understanding the enemy, in this case, bacteria that causes infections on implanted medical devices, is the key to success, say a team of researchers at the ithree institute, based at the University of Technology Sydney (UTS), the UTS School of Mathematical Sciences, Monash University, University of Melbourne and the Commonwealth Scientific and Industrial Research Organization, Australia.

Fig. 1 – A scanning electron micrograph of Pseudomonas aeruginosa bacteria. (Credit: CDC/ Janice Haney Carr)
Associate Professor Cynthia Whitchurch says they’ve made a breakthrough. Using a sophisticated imaging system, the scientists were able to study how bacteria form biofilms. They found that it secretes a DNA, which acts as a glue, binding hundreds of the cells together. Those cells then form tiny furrows, or trails, as they colonize the surface of implanted medical devices like catheters, pacemakers, and joint replacements. These antibiotic-resistant biofilms, where groups of cells stick to each other on a surface, are responsible for many recurring infections in hospitals and other medical facilities.

As reported in the journal, Proceedings of the National Academy of Sciences, Whitchurch says “What we found is that bacteria are able to build their own sort of road network, and that they can manage traffic flow throughout that road network to enable really rapid expansion of their biofilms across surfaces.”

The researchers used advanced microscopy techniques, including the next generation imaging system OMX Blaze, and sophisticated computer vision analysis to explore how bacterial biofilms spread. Studying the bacteria Pseudomonas aeruginosa, helped the team deduce how individual cell movements are coordinated and how intricate networks of interconnected trails are formed during biofilm expansion. (See Figure 1)

They discovered that groups of bacteria build and migrate along a “furrow” on a surface, and that extracellular DNA (eDNA) acted not as coding molecules but as a structural “rope” that guide the transit of the bacteria, which ensures a smooth flow of bacterial cells down the line towards the front of an expanding biofilm. eDNA also acts as glue, binding groups of bacteria together.

One way to solve this, they say, is instead of allowing the bacteria to create their own furrows, they’d like to create their own furrows in the surface of a catheter, directing the biofilm to “run in futile circles…so that their rate of migration along the catheter is significantly inhibited.”

The ithree institute based at the University of Technology Sydney (UTS) brings together an internationally competitive team focused on addressing key challenges in the understanding and control of infectious diseases in humans and animals. The institute’s innovative science uses a systems biology approach to develop a greater insight into basic biology and its application to the diagnosis, treatment, and prevention of infectious diseases.