2 Other ways to kill bacteria

Unlike quorum sensing, some antibiotic alternatives are bactericidal. Just like the bactericidal antibiotics you looked at in Week 2, these treatments work by killing the bacteria that cause infections.

In Week 4, you learned about the horizontal gene transfer mechanism of transduction. In this process, DNA is transferred between bacteria via infection with viruses known as bacteriophages.

Bacteriophages can also be exploited to treat infections. When bacteriophages infect bacteria, they replicate and assemble new virus particles, before lysing (bursting) and killing the bacteria, releasing the new bacteriophage particles (Figure 4).

Figure 4 The lytic cycle of a bacteriophage.

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This schematic diagram shows the steps of a single lytic cycle: infection, replication and assembly, then lysis and progeny release. Successive cycles in new host bacteria result in self-amplification. In the electron micrograph on the right of the figure, the phage particles appear as white spheres about 60 micrometres in diameter among the strands of cell debris.

Figure 4 The lytic cycle of a bacteriophage.