A Pilot Study to Determine the Effectiveness of Copper in Reducing the Microbial Burden (MB) of Objects in Rooms of Intensive Care Unit (ICU) Patients

Background: The roles of the neither the environment for transmission of microbes in hospitals, nor the effectiveness of measures to reduce the MB in the patient care environment have been adequately described.

Objective: To conduct a pilot study to assess the ability of copper to reduce the MB associated with objects in the patient care environment.

Methods: Copperized (Cu) objects (bed rails (99.99% Cu alloy), tray tables (90% Cu alloy), chair arms (90% Cu alloy), call buttons (70-95% Cu alloy), monitors (90% Cu alloy), and IV poles (75-95% Cu alloy)) were placed into three randomly selected ICU rooms. These objects were sampled by the sterile wipe technique weekly for 9 weeks from 7/27/09-9/28/09 and the MB for each object and each room (sum of MB of all objects) determined as colony forming units (cfu)/100cm². The mean (m) MB associated with each room and each Cu object was compared to the mMB measured by sampling the same non-copperized (non-Cu) objects in three randomly selected control ICU rooms. The efficacy of copper was calculated as the difference in mMB between the Cu and non-Cu objects and rooms. Environmental cleaning regimens did not change over the study period. The Kruskall-Wallis Test was used to compare means.

Results: 282 Cu objects in 32 rooms and 288 non-Cu objects in 27 rooms were sampled. Copper was effective in significantly reducing the total mMB of the patient ICU room by 87.4% (mMB 26,927 cfu/100cm² in non-Cu rooms vs. 3,391cfu/100cm² in Cu rooms, p=0.003). Copper was also effective in reducing the mMB on 4 of the 6 objects (bed rails by 99% mMB 18,417 cfu/100cm² vs. 240 cfu/100cm², p=0.0003; chair arms by 38% mMB 3,164 cfu/100cm²  vs. 1,962 cfu/100cm², p=0.11; call buttons by 90% mMB 4,548 cfu/100cm²  vs. 463 cfu/100cm², p=0.003; and IV poles by 67% mMB 418 cfu/100cm² vs. 139 cfu/100cm², p=0.11). Copper showed no reduction in the mMB on tray tables (mMB 323 cfu/100cm² vs. 509 cfu/100cm²) or monitors (mMB 57 cfu/100cm² vs. 78 cfu/100cm²). Staphylococcus was the predominant organism isolated from each individual object whether it was isolated from Cu or non-Cu objects and comprised 78.7% of the mMB of Cu rooms and 55.5% of non-Cu rooms. Of note, although MRSA and VRE were frequently isolated from non-Cu objects, they were never isolated from Cu objects.

Conclusions: Copper was effective in significantly reducing the total mMB by 87.4% in ICU patient care rooms and on many individual objects within those rooms. Significant reduction was seen when bed rails and call buttons were Cu and these items accounted for 85.3% of the total mMB seen in the non-Cu rooms. Further study regarding the effectiveness of placing Cu objects, particularly Cu bed rails and call buttons, into patient care environments in reducing the MB as well as acquisition of epidemiologically important organisms and healthcare acquired infections is needed.