Inclusion Criteria (index patient):  Confirmed clinical infection caused by Staphylococcus aureus infection, including skin and soft tissue infection (SSTI) or infection of a normally sterile site. Participant is willing and able to give informed consent for participation in the study. Male or Female greater or equal to 18 years old. Household is within one day's travel of the Hospital.  Inclusion Criteria (household contact):  Resident in the same household as index participant. Participant is willing and able to give informed consent for participation in the study if greater or equal to 18 years old or the parent/legal guardian if participant is less than 18 years old. Likely continued household residence for at least 3 months from initial sample collection. Able to comply with study requirements.  Exclusion Criteria (index patient):  - Deemed unsuitable by the responsible clinical team/clinician (e.g. terminal illness).  Exclusion Criteria (household contact):  Not a resident of the household at the time of the index patient hospital admission. Deemed unsuitable by the responsible clinical team/clinician (e.g. terminal illness) At least 4 household contacts already enrolled to this study.