Role of the Microbial Burden in the Acquisition and Control of Healthcare Associated Infections: The Utility of Solid Copper Surfaces - Use of Biocidal Surfaces for Reduction of Healthcare Acquired Infections - page 67

made between contaminated surfaces by VRE and subsequent VRE infection
[ 46 ]. In another study where the environments of patients colonized or infected
with VRE were evaluated upwards of 37 % of the environmental samples collected
were found to harbor VRE [ 31 ]. The samples included patient gowns, medical
equipment used for care, as well as environmental surfaces [ 31 ]. Controlling the
spread of VRE to subsequent room occupants is challenging in that this microbe can
be resistant to the disinfectants used for routine and terminal cleaning; even the use
of bleach-based products have been reported to fail in their ability to eradicate the
microbe from surfaces [ 22 , 24 ] (See also Chap. 9 ) .
Independent of cleaning, the issue of transference of pathogens from the envi-
ronment to subsequent occupants can be inferred from studies demonstrating the
long-term survival of the microbes on surfaces within the built environment. MRSA
and other nosocomial pathogens, including VRE and C. difficile can survive for
months on dry surfaces (Chap. 2 and ref [ 42 ]). MRSA has been documented for its
ability to survive within hospital dust for up to a year [ 89 ]. Further, frequently
touched hospital surfaces, such as doorknobs, have been implicated as reservoirs
from which pathogens can be routinely recovered and thus transferred [ 56 ]. MRSA,
like VRE, is ubiquitous in the hospital environment, especially in the vicinity
of patients known to be colonized or infected [ 22 , 24 ]. The chief method of spread
is poor compliance with infection control measures, such as hand hygiene, by
healthcare workers. Several studies have described endemic and epidemic contam-
ination of the environment with MRSA. A recent review by Dancer and colleagues
found that the site contamination mean for common objects in the patient's room
with MRSA was 37 %, with high percentages found for such surfaces as overbed
tables (40 %), bed rails (27 %), and other furniture (27 %) [ 23 ].
The risk of acquiring MRSA or VRE by a patient being admitted into a room that
was previously occupied by a patient known to harbor MRSA or VRE was
described by Huang and colleagues [ 37 ]. The added risk of acquisition of MRSA
to the 10,151 'eligible' patients examined by their study was found to increase by an
adjusted odds ratio of 1.4 (p

0.04). Specifically, amongst the patients whose prior
room occupant was MRSA positive (n ¼ 1,454), 3.9 % of this cohort acquired
MRSA, while only 2.9 % of the patients who occupied a room previously housing
a MRSA negative patient (n

¼

8697) acquired MRSA. A similar risk profile of
acquisition of the drug resistant microbe was similarly observed with VRE. Here
4.5 % of patients who occupied a room that previously housed a VRE positive
patient (n

¼

1,291) developed VRE while the infection rate in patients housed in
rooms previously occupied by a VRE negative patient (n

¼

9,058) had an attack

¼

rate of 2.8 % (adjusted odds ratio of 1.4; p 0.02). The authors concluded that

acquisition from previous occupants accounted for 40 % increased odds of trans-
mission of MRSA and VRE strongly suggesting a role for environmental contam-
ination, despite room cleaning methods that exceeded the national standard [ 37 ]. A
review of the topic of the risk of nosocomial pathogen acquisition from prior room
occupants was recently published [ 58 ]. Here Otter and colleagues reviewed the
increased risk associated with other MDR microbes. Again the trend was the same.
Patients who occupied rooms where the former patient was infected or colonized

¼