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.”
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