Population Dynamics of Nasal Strains of Methicillin‐Resistant<i>Staphylococcus aureus</i>—and Their Relation to Community‐Associated Disease Activity

Abstract

Comparison of MRSA strains from asymptomatic carriers versus concurrently collected community-associated clinical strains from patients treated at local health-care facilities allowed for the identification of 3 population dynamics of nasal strains of MRSA: (1) endemic clones--for example, ST8:C and ST59:P--sustained asymptomatic carriage and infection over prolonged periods; (2) an epidemic clone, ST8:S, demonstrated enhanced capacity for rapid transmission and widespread infections; and (3) an outbreak clone, ST30:Z (USA1100), was highly infectious but exhibited poor asymptomatic transmission.