Data were entered directly into a study-specific Microsoft Excel database (Microsoft, Redmond, WA). Organisms were defined as curtain-acquired if they were present on a HCW's postcurtain imprint only. Pathogens were defined as organisms which are not commensal. Median differences were calculated using a related-samples Wilcoxon signed-rank test, and 95% confidence intervals (CIs) were estimated using related-samples Hodges-Lehmann methods. All analyses were performed using SPSS 22.0 (IBM, Somers, NY).