Staphylococcus aureus
Plain-English definitions of microbiome research vocabulary — the terms you'll see across articles, testing services, and probiotic claims.
A common bacterium that colonises the skin and nasal passages. While often harmless, S. aureus is an opportunistic pathogen implicated in wound infections, food poisoning, and skin conditions. In eczema, S. aureus overgrowth during flares is a consistent finding, driving inflammation through superantigen production.
Related terms
Staphylococcus epidermidis
One of the most abundant commensal bacteria on human skin. S. epidermidis produces antimicrobial peptides that inhibit pathogenic bacteria including S. aureus, communicates with the immune system, and helps maintain the skin's acidic pH. Often called the "good staph."
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.