What term describes the presence of microorganisms but without multiplication and effects on the host?

The term that describes the presence of microorganisms without multiplication and effects on the host is contamination. In microbiological terms, contamination refers to the situation where microorganisms are present in a specific environment or on a surface, but they do not grow or produce harmful effects in that context. This is important in understanding how different organisms can exist in various settings without necessarily causing harm or leading to an active infection.

In contrast, infection typically implies that microorganisms have entered a host and are multiplying, potentially causing disease. Pathogenicity refers to the ability of an organism to cause disease, which again involves multiplication and interaction with the host's biological systems. Colonization means that microorganisms have established themselves in a host and may be multiplying, but this does not always lead to disease. Therefore, contamination accurately describes the scenario where microorganisms are present but are not causing an infection or significant impact on the host.