Definition of pathogen and commensal microbiota

In biology, a pathogen, in the oldest and broadest sense, is anything that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term pathogen came into use in the 1880s. Commensal microbiota represents an ensemble of microorganisms that reside in close proximity and in mutualistic relation with a host organism. ... Gut microbiota (formerly called gut flora) is the name given today to the microbe population living in our intestine. #pathogen #commensalMicrobiota #immunology