What term describes the condition when the body is invaded by bacteria?

The term "infection" specifically refers to the condition when the body is invaded by pathogenic microorganisms, such as bacteria. In the context of microbiology and health, an infection occurs when these bacteria enter the body, survive, and multiply, potentially leading to damage to tissues and an immune response. This can manifest in various ways, depending on the type of bacteria and the site of infection.

Contamination refers more broadly to the presence of bacteria or other microorganisms on a surface or substance. While contamination can precede an infection, it does not imply that the microorganisms are actively invading or causing harm.

Infestation typically relates to the invasion by larger parasites, such as insects or worms, rather than bacteria, making it an inappropriate term for this context.

Colonization indicates that bacteria are present in a certain area of the body and can multiply without causing disease. While colonized bacteria can potentially lead to infection if they penetrate tissues or if the host's immune system is compromised, colonization itself does not equate to infection, as it does not always cause harm.

Thus, "infection" accurately describes the state where harmful bacteria invade the body and potentially lead to illness.