An Overview of the Options for Antimicrobial Hard Surfaces in Hospitals - Use of Biocidal Surfaces for Reduction of Healthcare Acquired Infections - page 144

The introduction of hospital textiles with antimicrobial activity is another
option, which is reviewed elsewhere [ 55 , 59 ]. The optimal deployment mode for
AMS is unclear: should AMS be manufactured-in or periodically applied, or are
ways to make the surface physically less able to support contamination or easier to
clean preferable? Furthermore, it may be possible to make a surface physically less
able to support contamination, easier to clean and exert AMS properties.
To permanently manufacture-in an AMS is advantageous for a number of reasons.
There is no concern with the adhesion and durability of a coating, and the various
issues associated with application are not a concern, for example, frequency, cost
and thoroughness. However, it is probably not feasible to manufacture-in the same
AMS for all items in a room, limiting this mode of deployment to a fairly small
number of high-touch items in real terms. Another approach is to periodically apply
an agent that offers residual AMS properties. If periodic application is selected, the
frequency and durability of application are key concerns. An effective disinfectant
with residual activity that does not compromise staff or patient safety or promote the
development of reduced susceptibility is desirable, and could be delivered through
pre-existing cleaning and disinfection arrangements at little or no extra cost.
7.2.1 Considering the 'Ideal' Antimicrobial Surface
Although not achievable with currently available candidate technologies, a consid-
eration of the properties of an 'ideal' antimicrobial hospital surface is helpful:
￿ Versatile application. Ideally, the active ingredient would have the capacity to
be manufactured-in or applied as liquid agent.
￿ Non-leaching. This will mean that the surface remains antimicrobial for its
lifetime. Furthermore, the efficacy of AMS that rely on leaching an active
agent from a surface may be considerably less effective in a dry environment
and should be tested accordingly.
￿ Rapid antimicrobial activity. The deposition of contamination and potential
acquisition of contamination through contact with surfaces often occurs in
quick succession, so antimicrobial surfaces with a contact time measure
in hours (rather than minutes or seconds) may be too slow to be useful.
￿ Sporicidal. C. difficile spores represent a real challenge to antimicrobial
surfaces. Copper seems to get closest to demonstrating inactivation, but even
here data are somewhat equivocal [ 60 ]. There is a legitimate concern that
introducing an AMS that is not effective against C. difficile could provide a
selective advantage to C. difficile.
￿ Retains activity with low-level soiling. Surfaces in hospitals are often dirty; it's
not clear how much the presence of organic matter would interfere with the
activity of AMS. Clearly, AMS do not obviate the need for careful attention
to hospital cleaning and disinfection. In fact, their continued effectiveness
depends on it.