The evolution of bacteria on a “Mega-Plate” petri dish: Bacteria (white) grow on a large petri dish with increasing concentrations of antibiotic (trimethoprim) in bands towards the center. Evolution of antimicrobial resistance can be seen as mutants with higher antibiotic resistance are able to colonise the more central regions. By the 11th day of evolution, variants with 1000x higher antibiotic resistance have colonised the central band.
