The structure you see above has been nicknamed a "comet", but it's really bacteria streaking across an agar plate. Scientists have found out that superbugs, antibiotic resistant bacteria, can move, helping them spread and establish new colonies.
Some bacteria have little tails. Methicilin-resistant Staphylococcus aureus does not. Some have many tiny hairs all around their body. S. aureus does not. Some are, at least, pressed into an oblong shape that helps them move. Not S. aureus. It's a little roly-poly sphere that shouldn't be able to move anywhere, but, to quote Galileo, "And yet it moves."
This is what scientists at the University of Nottingham in England discovered when they used time-lapse microscopy to create this video. As described in a new paper published in Nature, the bacteria first multiply, creating a matrix of slime to keep them grouped together. Then they send little tentacles of bacteria, called dendrites, out in front of them. Finally, they move forward using the dendrites, leaving a trail of bacteria behind them.
Researchers call the practice of leaving that trail of bacteria "seeding", as it lays the ground for more colonies. The seeds aren't completely motionless themselves. They follow the head of the comet for a while — it's only after most of the seeds stop moving that the comet moves on.
It's not great news for those people who want their surfaces to stay clean of antibiotic resistance bacteria. But it's an interesting insight into bacterial behaviour.