Pathobiont
Plain-English definitions of microbiome research vocabulary — the terms you'll see across articles, testing services, and probiotic claims.
A normally harmless commensal organism that can become pathogenic under certain conditions, such as immune suppression, antibiotic use, or disrupted gut barrier. Many gut bacteria are pathobionts rather than true pathogens.
Related terms
Commensal
An organism that benefits from a relationship with another organism without causing harm. Most gut bacteria are commensals — they gain food and shelter while contributing to digestion, immunity, and barrier function.
Dysbiosis
An imbalance in the composition or function of the microbiome, typically characterised by reduced diversity, loss of beneficial bacteria, or overgrowth of potentially harmful species.