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 68

with Pseudomonas aeruginosa or A. baumannii [ 55 ], or C. difficile [ 81 ] resulted
in a similar increase risk of acquiring the previous occupants pathogen.
A study in 2011 showed that a prior room occupant with a CDI was a significant
risk factor for CDI acquisition by the subsequent occupant [ 81 ]. This spore-forming
anaerobic bacterium can survive for many months on hospital surfaces and is
recalcitrant to usual cleaning methods [ 36 ]. Studies have shown very high environ-
mental surface contamination rates, particularly in areas within close proximity to
the patient. In a trial conducted in France, approximately 25 % of healthcare
workers who were caring for patients with a CDI were found to have C. difficile
spores associated with their hands [ 43 ]. The authors concluded that contamination
of the hands was positively associated with exposure to fecal soiling and lack of
glove use.
Several Gram-negative nosocomial pathogens, such as P. aeruginosa and
A. baumannii , increasingly associated with multi-drug resistance, have similarly
been recovered from high touch surfaces such as beds, tables, and infusion pumps
[ 5 ]. Outbreaks, thought to have occurred because of patient to patient spread of
MDR Gram negatives, can be devastating to patients and hospitals, resulting in high
numbers of cases and high morbidity and mortality. Responses have included
robust and aggressive approaches towards infection control often including
enhanced environmental cleaning and in extreme cases closure of the affected
unit or substantial areas of the hospital [ 25 , 27 , 45 ]. Fortunately, the majority of
the clinically relevant Gram-negative microbes associated with the built clinical
environment are not viable after drying. Half-lives routinely encountered are 7 h or
less [ 36 ].
An emerging nosocomial fungal pathogen, which has become a common cause
of central line associated bacteremia in healthcare, is Candida albicans . There are
fewer studies documenting the extent of environmental contamination with fungi;
however, C. albicans has been shown to be able to survive anywhere from 3 days to
up to 4 months on inanimate surfaces [ 42 ]. The majority of Candida infections are
likely from endogenous sources. However, through molecular typing, evidence of
transmission via environmental sources has been suggested; identical strain types
were recovered from patients infected with Candida and from hospital surfaces
from the rooms of the affected patients [ 88 ].
There are several classes of pathogenic viruses that can be found on hospital
surfaces. Respiratory viruses such as influenza, coronavirus, and rhinovirus can
persist on surfaces for a few days [ 42 ]. Viable influenza virus can be transferred
from surface to skin, leading to the potential transfer to patients [ 36 ]. Gastrointes-
tinal tract viruses, such as rotavirus and astrovirus, can persist for around 2 months
[ 42 ]. Rotavirus is a well-known cause of gastrointestinal illness outbreaks, espe-
cially in day care centers where it is spread through contamination of toys
[ 36 ]. Norovirus has been shown in several studies to be consistently transferred to
frequently touched sites in a hospital, such as door handles and telephones [ 24 ].
Closure of units and deep environmental cleaning similar in scope, time and
expense seen with MDR-Gram negative outbreaks are often needed to control
Norovirus outbreaks in hospitals.