Timelapse microscopic footage of a colony of Escherichia coli bacteria growing and dying in the presence of the antibiotic drug penicillin. Penicillin is a beta-lactam antibiotic derived from the Penicillium sp. mould. The drug works by interfering with the formation of the bacterial cell walls. By preventing the formation of the cell wall during replication and growth, the bacteria lose integrity and then rupture and die. This can be seen here as the bacteria grow and then burst and suddenly pale and disappear. Penicillin was first isolated in 1928.