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Contamination of the hospital environment contributes to the acquisition of multidrug-resistant organisms and the development of hospital-acquired infections (HAIs) — a realization that has led to increasing emphasis on disinfection. But might changing surface materials also be beneficial? Two new studies suggest that the use of copper-alloy surfaces could be effective in decreasing HAIs. (One of the authors, who participated in both studies, is employed by the Copper Development Association.)
Schmidt and colleagues compared the bacterial burden (BB) on copper-covered and standard plastic bedrails in a medical intensive care unit (ICU) over a 3-month period, with no changes in medical or housekeeping practices. The mean BB in samples obtained immediately before room cleaning was significantly lower for the copper-covered bedrails than for the standard ones (698 vs. 6102 colony-forming units [cfu] per 100 cm2); a significant difference persisted for at least 6.5 hours. Seventy-seven percent of copper-covered bedrails versus 45% of standard bedrails had BBs <250 cfu per 100 cm2 (considered low risk for subsequent HAIs) immediately after terminal cleaning.
Salgado and colleagues performed a prospective, controlled trial in three medical centers to assess the acquisition of HAIs and methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE). A total of 8 standard ICU rooms, 8 ICU rooms with copper-covered objects (bedrails, over-bed tables, intravenous poles, arms of visitor chairs, nurses' call buttons, select in-room computer equipment), and 614 patients were involved. Compared with patients in the standard rooms, those in the rooms with copper-covered objects had lower rates of National Healthcare Safety Network–defined HAIs (3.4% vs. 8.1%; P=0.013), colonization with MRSA or VRE (1.4% vs. 3.8%; P=0.063), or the composite endpoint of either HAI or colonization (7.1% vs. 12.8%; P=0.020). Across all the study rooms, environmental BB was significant associated with HAI risk.
Schmidt MG et al. Copper continuously limits the concentration of bacteria resident on bed rails within the intensive care unit. Infect Control Hosp Epidemiol 2013 May; 34:530. (http://dx.doi.org/10.1086/670224)
Salgado CD et al. Copper surfaces reduce the rate of healthcare-acquired infections in the intensive care unit. Infect Control Hosp Epidemiol 2013 May; 34:479. (http://dx.doi.org/10.1086/670207)
Comment
Together, these two studies provide clinical evidence that copper-alloy surfaces lower the risk for hospital-acquired infections and transmission of multidrug-resistant organisms, as well as a biological rationale for this effect. However, as Salgado and colleagues acknowledge, because of copper's distinctive appearance (and perhaps odor), their study was not effectively blinded, and unrecognized imbalances in hand hygiene or housekeeping practices might have contributed to the observed findings. In addition, the study was not powered to assess which HAIs were more likely to be influenced by a reduction in bacterial burden. Still, this work justifies future research on the use of copper-alloy or other self-disinfecting surfaces in the healthcare environment.