Superbug colony behaviours revealed in time lapse video

A well-known ‘superbug’ which was thought to have been a static or non-motile organism has been observed showing signs of active motility by scientists at The Universities of Nottingham and Sheffield.  

Methicillin-resistant Staphylococcus aureus, or MRSA, is the bug responsible for several infections in humans ranging from superficial to life-threatening which are difficult to treat because of antibiotic resistance. Now for the first time the scientists have shown that S. aureus, a spherical bacterium with no propulsive tail or appendages, may be capable of a form of ‘active’ motility and moving independently.

Motility is central to bacterial behaviours, such as biofilm formation, virulence and host colonisation so the discovery, published in Scientific Reports could have implications for future clinical treatments.

Dr Steve Diggle from The University of Nottingham’s School of Life Sciences, said: “Our research has focused on observing the formation of dendrites – branch-like structures that emerge from the central colony of bacteria. Using high powered microscopy, we saw that the bacteria can spread across the surface of an agar plate in structures that we have called ‘comets’. These advance outwards and precede the formation of dendrites. We have observed and photographed the comets ‘seeding’ cells behind them, without losing mass, which then grow into observable dendrites.   “After 8 hours of colony growth, the comet heads are the main source of movement. Cells in the tail follow the comet heads for a while while bacteria further away no longer move. Our time-lapse video shows the whole remarkable process.”