Microorganisms that are normally commensal and do not harm their host but can become pathogenic and cause infection when the host's immune defences are compromised.

Membrane-bound components of eukaryotic cells that are specialised to carry out particular functions.

The process by which water moves through a partially permeable membrane from a less concentrated solution of, for example, salt (where there is a relatively high concentration of water and a low concentration of salt) to a more concentrated one (where there is a relatively low concentration of water and a high concentration of salt).

Capable of causing disease.

A penicillin-binding protein with low affinity for penicillin and other β-lactams.

Bacterial enzymes that are essential for bacterial cell wall synthesis. They are the target of β-lactam antibiotics.

A major component of bacterial cell walls. A large polymer, consisting of sugars and amino acids, that forms a mesh-like layer outside the bacterial cell membrane.

Treatment for bacterial infections that exploits the ability of bacteriophages to lyse and kill the bacteria they infect.

The characteristics of a drug that relate to how it is used and its effects in the body.