Bacterial burden is associated with increased transmission to health care workers from patients colonized with vancomycin-resistant Enterococcus

Background: Health care workers (HCWs) are significant vectors for transmission of multidrug-resistant organisms among patients in intensive care units (ICUs). We studied ICU patients on contact precautions, colonized with vancomycin-resistant Enterococcus (VRE), to assess whether bacterial burden is associated with transmission to HCWs’ gloves or gowns, a surrogate outcome for transmission to subsequent patients. Methods: From this prospective cohort study, we analyzed 96 VRE-colonized ICU patients and 5 HCWs per patient. We obtained samples from patients’ perianal area, skin, and stool to assess bacterial burden and cultured HCWs’ gloves and gowns for VRE after patient care. Results: Seventy-one of 479 (15%) HCW-patient interactions led to contamination of HCWs’ gloves or gowns with VRE. HCW contamination was associated with VRE burden on the perianal swab (odds ratio [OR], 1.37; 95% confidence interval [CI], 1.19, 1.57), skin swabs (OR, 2.14; 95% CI, 1.51, 3.02), and in stool (OR, 1.95; 95% CI, 1.39, 2.72). Compared with colonization with Enterococcus faecalis, colonization with Enterococcus faecium was associated with higher bacterial burden and higher odds of transmission to HCWs. Conclusions: We show that ICU patients with higher bacterial burden are more likely to transmit VRE to HCWs. These findings have implications for VRE decolonization and other infection control interventions.