STAG3 and infection: These were the apparent loss of ɸSa3 in the initial infection isolate of subject 18 and the first throat culture of subject 15 and the apparent gain of ɸSa5 in the first perirectal isolate of subject 10 and the initial infection isolate of subject 16 (although based on its deep branching, the initial infection isolate may represent a separate colonization event from other strains isolated from subject 16).