noun
resident flora; resident bacteria; commensal microbiota
Medical term for microorganisms that normally live on or in the body without causing disease under usual conditions. Often contrasted with transient or pathogenic bacteria.
皮膚には多くの常在菌が存在している。
Many resident bacteria are present on the skin.
Resident flora normally do not harm healthy individuals.
Pathogenic bacteria that cause disease, as opposed to the normally harmless resident flora.
Compound of 常在 (じょうざい, 'always present') and 菌 (きん, 'bacteria/germ'). The term is a modern medical coinage.