Microorganisms that live below the skin and are difficult to remove are referred to as what?

Microorganisms that are classified as resident flora are those that establish themselves and thrive on or within the human body, particularly in locations such as the skin, gastrointestinal tract, and mucosal surfaces. These organisms play a crucial role in the body's ecosystem, often participating in various metabolic processes and contributing to the host's health by preventing the colonization of pathogens through competitive inhibition and immune system modulation.

Resident flora are typically well-adapted to their specific niches in the body, making them challenging to remove completely through standard hygiene practices. In contrast, transient flora may be present temporarily and can be removed with routine washing or scrubbing. Pathogenic flora specifically refers to those microorganisms that can cause disease, while opportunistic flora are typically non-pathogenic or commensal but can cause infections when the host's immune system is compromised.

Understanding the distinction between these types of flora is essential for comprehending how normal microbial populations contribute to health and how disruptions might lead to infections or other health issues.