Fig. 3: Transmission of DNA-confirmed MRSA or VRE to participant hands or equipment.

a MRSA transmission to equipment. Of the 14 interactive visits where the participant hand was contaminated with MRSA before use, transmission of MRSA to a surface occurred at 4 (28.6%) visits. Ten MRSA transmissions to a surface occurred, of which 4 (40%) can be attributed to participant hand contamination. b MRSA transmission to participant hand. Of the 17 interactive visits where equipment or surface was contaminated with MRSA before use, transmission of MRSA to the participant’s hand occurred at 1 (5.9%) visit. Ten MRSA transmissions to a participant hand occurred, of which 1 (10%) can be attributed to surface contamination. c VRE transmission to equipment. Of the 36 interactive visits where the participant hand was contaminated with VRE before use, transmission of VRE to a surface occurred at 16 (44.4%) visits. Twenty-five VRE transmissions to a surface occurred, of which 16 (64.0%) can be attributed to participant hand contamination. d VRE transmission to participant hand. Of the 35 interactive visits where equipment or surface was contaminated with VRE before use, transmission of VRE to the participant’s hand occurred at 2 (5.7%) visits. Thirteen VRE transmissions to a participant hand occurred, of which 2 (15.4%) can be attributed to surface contamination. e Unadjusted odds ratios and confidence intervals for the association between surface contamination and participant hand colonization and transmission of MRSA and VRE. Reported p-values (two-sided) are based on generalized linear models specifying an exchangeable, within-participant correlation structure for the panels. Transmission of MRSA to a surface/equipment was 20.7 times more likely when the participant hand was colonized first, compared to when the participant hand is not colonized first (p = 2.5e-5), while transmission of MRSA to a participant hand is 2.2 times more likely when the surface/equipment is contaminated first (p = 0.451). Transmission of VRE to a surface/equipment was 21.3 times more likely when the participant hand was colonized first, compared to when the participant hand is not colonized first (p = 4.1e−10), while transmission of VRE to a participant hand is 1.7 times more likely when the surface/equipment is contaminated first (p = 0 .505). Source data are provided for this figure. Abbreviations: MRSA, methicillin-resistant Staphylococcus aureus; VRE, vancomycin-resistant enterococci; OR, odds ratio.