Which of the following best defines microbial colonization in the context of infectious disease?

• A. The establishment and persistence of a microorganism on or within a susceptible host where it can survive and potentially multiply.
• B. The transient carriage of microbes on skin or mucosa without any replication or interaction with host tissues, which disappears within minutes after contact.
• C. The process by which a pathogen reproduces exclusively outside a host in the environment and later contaminates fomites but never makes direct contact with host tissues.
• D. The process where a microbe passes briefly through the gastrointestinal tract without binding or growing but causes systemic immune activation solely due to antigen exposure from dead organisms present in food or water.

Answer: (A)