The Role of Contaminated Surfaces in the Transmission of Nosocomial Pathogens - Use of Biocidal Surfaces for Reduction of Healthcare Acquired Infections - page 47

level of room disinfection and thus reduce the increased risk of environmental
contamination by the prior room occupant [ 12 ]. Because areas or rooms must be
vacated for all NTD systems, they are best suited for terminal disinfection follow-
ing the transfer or discharge of patients infected or colonized with pathogens.
Available NTD systems include HPV systems [ 12 , 61 ], aerosolized hydrogen
peroxide (aHP) [ 147 , 148 ], and UVC [ 149 , 150 ] and pulsed-xenon (PX-UV)
[ 151 , 152 ] ultraviolet radiation. These systems have important differences in their
active agent, delivery mechanism, efficacy, process time and ease of use [ 83 ].
Typically, there is a trade-off between time and effectiveness, with the hydrogen
peroxide-based systems being more efficacious but the UV systems faster and
easier to use [ 83 ]. The choice of NTD system should be influenced by the intended
application, the evidence base for effectiveness, practicalities of implementation
and cost constraints (See also Chap. 9 ) .
3.8.3 Reducing and Controlling the Extent
of Environmental Contamination
In addition to improving the efficacy of cleaning and disinfection once contamina-
tion has occurred, steps can be taken to prevent, reduce or improve the containment
of shed pathogens. Rapid identification and isolation of affected patients could
reduce contamination of bays and open ward areas shared by unaffected patients
[ 153 ]. Identification and isolation of asymptomatic shedders may also have a role.
Asymptomatic carriers of C. difficile were a source of widespread contamination in
one study [ 41 ] and asymptomatic fecal carriage of small round virus (probably
norovirus) was common in another long-term care facility study [ 40 ]. Further work
is required to determine the extent and length of time that patients continue to shed
pathogens into the environment after the resolution of symptoms, particularly for
C. difficile and norovirus.
While hospitals in the US generally have a high proportion of single rooms,
hospitals in other countries typically have a much lower proportion of single rooms
[ 154 ]. The lack of isolation facilities hampers effective isolation of patients known
to be infected or colonized with pathogens. Where single rooms are not available,
cohorting of patients affected with the same pathogen within a multi-occupancy
area is often practiced [ 155 , 156 ]. However, increasing the number of single
rooms has been associated with reduced transmission [ 157 ]. Thus, hospitals and
healthcare administrators should ensure the adequate provision of isolation facili-
ties through building hospitals with a high proportion of single occupancy rooms or
modifying existing facilities to increase the proportion of single occupancy rooms
[ 154 , 156 - 158 ].
'Source control' through daily bathing with chlorhexidine is another approach to
reducing the shedding of pathogens, and this has been shown to reduce the
transmission of certain pathogens [ 56 , 159 - 162 ]. However, most studies of the