FIG 1.

Timeline showing dates of recovery of ST22-MRSA-IV isolates involved in cross-transmission events (CTEs) previously identified by conventional molecular epidemiological (CME) typing or identified as a pair of isolates recovered from a patient and his or her immediate ward environment. For each CTE, the putative source isolates recovered from patients (P) and the environment (E) as well as putative transmitted isolates (T) are shown, and for each pair of isolates, the patient and environmental isolate are also indicated. Isolate numbers are shown in brackets followed by the spa type, dru type, and PFGE type. The single nucleotide variant (SNV) comparison between each of the source isolates and the transmitted isolates within a CTE or between each pair of isolates is indicated by numerals within a square with the transmitted isolate SNV value denoted by 0 (0 SNVs resulting from self-comparison). CTEs were confirmed by SNV analysis if one or more of the source isolates differed from the transmitted isolate by ≤40 SNVs. For CTEs consisting of multiple source isolates of which some were confirmed and some were refuted as CTEs by SNV analysis, the isolate number for the CTEs either confirmed or refuted are indicated in the second to last column to the right of the figure. Pairs of isolates were confirmed as CTEs if the patient and environmental isolate differed by ≤40 SNVs. Further molecular epidemiological details of isolates implicated in each of the CTEs or as a pair of isolates are provided in Table S1 in the supplemental material and have been published previously (6, 7). NA, not applicable.