An Overview of the Options for Antimicrobial Hard Surfaces in Hospitals - Use of Biocidal Surfaces for Reduction of Healthcare Acquired Infections - page 154

activity of copper AMS was performed by Schmidt et al. [ 43 ]. The study was a
43-month prospective multicentre intervention study, which demonstrated that
the introduction of six copper high-touch AMS was associated with a significant
reduction in bacterial count through weekly sampling. The frequency of recovering
indicator organisms was also reduced.
A number of studies have also been performed on copper-containing liquid
biocides, demonstrating in vitro activity against MRSA and C. difficile spores
[ 91 , 92 ]. An in situ study showed that microfiber impregnated with a copper biocide
were more effective at inactivating bacteria on hospital surfaces than microfiber
impregnated with water [ 68 ]. However, a chemical disinfectant without residual
activity would have been a more suitable control for this experiment.
A recently study is the only published study with a clinical outcome for any
AMS [ 31 ]. The study design was a multicentre evaluation of the clinical impact of
introducing six copper alloy high-touch sites into the rooms of patients on three
ICUs. Patients (n 614 following exclusions) were randomized to intervention

'copper' rooms and control 'non-copper' rooms in three USA ICUs over an
11 month period. The only difference between the rooms was the presence of six
items made of copper alloy, comprising bedrails, overbed tables, IV poles and
visitor chair arms in all rooms and the nurse call button, computer mouse, computer
palm rest and rim of a touch-screen monitor in other rooms.
Patients admitted to copper rooms were significantly less likely to acquire HAI
or colonization with MRSA/VRE. The authors also make an interesting association
between the degree of contamination in patient rooms and the risk of acquisition
(Fig. 7.1b ). However, since sampling was performed weekly regardless of a
patient's infection or colonization status, it is not possible to determine whether
this association is causal or simply due to the fact that infected/colonized patients
are likely to shed more bacteria into the hospital environment.
The study was designed carefully and executed with strong attention to detail.
For example, they performed a daily census of the items in the study rooms to
determine exactly who was exposed to copper surfaces, and for how long. This
indicated that only half of the patients in 'copper' rooms were exposed to all six
copper items for the duration of their stay, and 13 % of patients in the 'non-copper'
arm were exposed to some copper items during their stay. It's important to note that
the analysis was performed on an 'intention-to-treat' population, i.e. all patients
randomized to the two groups, regardless of which items they were actually
exposed to. It would have been interesting to see a sub-analysis on the 'per
protocol' population (i.e. those patients admitted to 'copper' rooms and exposed
to all six copper items vs. those patients admitted to 'non-copper' rooms and
exposed to no copper items). Also, the authors reported the percentage of patients
who acquired HAI or colonization, rather than a comparison of rates between the
groups. Indeed, a letter published raised some questions over the validity of the
analysis methods chosen, and the plausibility of the findings [ 78 , 79 ]. However, it
seems that the introduction of a handful of copper alloy high-touch sites had a
profound impact on HAI rates. However, questions remain over the practicality and
durability of the widespread adoption of copper alloy surfaces in healthcare.

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