Phylogenetic analysis of S. aureus isolates. (a) The first isolate for each patient in the biorepository is included. Reference strains are labeled. Concentric circles represent CC/ST, mec type (only types II and IV were represented in this collection of isolates; if no mec type is indicated, the strain is mec negative), SARS-CoV-2 PCR result, and isolate source. (b) agr type and (c) agr mutations analyzed by SARS-CoV-2 PCR result. A disruptive agr variant was defined as a frameshift or stop gain. ** = reference strain CA-347. CC = clonal complex, ST = sequence type, “NA” = other or not categorized.