Special Edition on Infection Prevention & Control | Page 25

his or her own specialties and expertise but bringing them
together can synergize in a way that is greater than the sum
of its parts.”
In their study, Dalton, et al. (2020) used a One Health lens to
describe the relationship between the hospital environment and
patient care specifically for Gram-positive hospital-associated
pathogens, and to identify how animals fit into this relationship.
As they explain, “This review focuses on Gram-positive bacterial
pathogens, a significant cause of HAIs, which may survive
longer on dry surfaces than Gram-negative bacteria. MRSA
was the first pathogen where spread through the hospital
environment was documented, though targeted hospital
efforts are contributing to its decline in the past decade. It
is relevant to One Health, as some MRSA strains and other
multidrug-resistant staphylococci are associated with animals,
livestock in particular.”
The researchers add that the second most common
hospital-associated Gram-positive pathogen is Clostridioides
difficile, and they included it in their review because it is the
most common hospital-acquired infection pathogen (about
500,000 infections annually with up to 30,000 deaths in the
U.S.) and antibiotic prescribing for other infections (such as
MRSA) can be a risk factor for C. difficile infection; conversely,
treatment with the recommended vancomycin protocol has
been shown to lead to the researchers’ third Gram-positive
pathogen of concern -- vancomycin-resistant Enterococcus
(VRE). They note, “While not credited with the same degree
of pathogenicity as MRSA or C. difficile, VRE causes infections
in vulnerable patients, including outbreaks that are difficult
to control due to its resistance to routine cleaning. All three
important Gram-positive pathogens are able to survive in the
environment for days to months and have low infectious doses—as
low as 5 spores (C. difficile) or 4 CFUs (MRSA)— where
inadequate environmental approaches can pose an ongoing
risk of transmission to hospital patients.”
As Dalton explains, “We decided to focus on Gram-positive
organisms for the scope of this paper just because more research
has been published within this group. That being said, I think this
framework could be applied to any infectious microorganism,
as well as viruses, and even extend it to injury prevention
and other hospital hazards. The One Health framework can
be used broadly for its emphasis on those core concepts of
multiple-stakeholder engagement and systems-thinking that can
be applied to many concerns within the healthcare institution.”
One of those big issues of concern is the role that the
hospital environment plays in HAI prevention and control.
As Dalton, et al. (2020) observe, “Critical to a One Health
approach is the role of the environment, including the unique
characteristics of the built environment. The built environment
is defined as the infrastructure created by people for spaces
where they live and work, with consideration for how physical
properties of these buildings influence health. The hospital
environment can facilitate transmission of pathogens responsible
for HAIs. The inanimate environment can be a MDRO
reservoir, with environmental contamination responsible for
approximately 10 percent to 30 percent of patient MDRO
acquisitions.” They add, “Contamination of high-touch surfaces
with MDROs such as MRSA, VRE and Clostridioides difficile
for prolonged time periods has been well documented, and
thus can serve as a potential reservoir for onward infections to
I think the push now is to bring together the expertise
of all stakeholders, integrate the knowledge
of all these different experts together, and bring it
to bear against HAIs and other challenges.”
patients and healthcare workers. Multiple studies have shown
that there is higher HAI risk for patients who are in rooms that
were previously occupied by an HAI-positive patient, even after
routine cleaning and disinfection.”
The researchers explain that other factors in the environment
contribute to HAIs, including:
● Aspects of the hospital’s built-environment and design
can influence microbial transmission, including different
surface materials; private versus open shared patient rooms;
and hospital size and higher patient density and clustering.
● Hospital fomites, or the inanimate objects which can
become contaminated with pathogens and serve as sources
for contamination and potential colonization for individuals
who come in contact with them. Other possible dissemination
routes for pathogens is airborne dispersion, promoting spread
among the hospital environment and individuals.
● The hospital microbial ecosystem, with the hospital
built-environment serving as a source for other microorganisms
that are less often pathogenic but can serve as potential
reservoirs of resistant genes. As the researchers explain,
“Understanding other potential sources of antimicrobial-resistant
genes is fundamentally important in combating and
understanding MDRO epidemiology. Bacterial diversity also
varies among different hospital areas – it has been shown that
the halls, living rooms, patient rooms, and rest rooms exhibit
more diverse bacterial compositions than that of the isolated
ICU. Different ICU management practices, including more
rigorous sanitation protocols, could exert selective pressure
and foster survival of microorganisms that express genes for
resistance to common disinfectants and antimicrobial agents.”
Human factors and patient characteristics also are a big
component of the HAI and One Health dynamic. As Dalton,
et al. (2020) emphasize, “Human factors are critical when
assessing One Health in hospitals in the context of HAI
transmission. According to some estimates, 5 percent to 10
percent of patients will develop an infection while in the
hospital. Multiple studies have shown that around 10 percent
of patients who enter hospitals are asymptomatically colonized
with at least one type of MDRO, emphasizing the substantial
influx of MDRO from community settings into the hospital …
Established factors associated with increased risk of nosocomial
infection include prolonged antimicrobial therapy, comorbidity
with chronic health conditions, compromised immune function,
and close proximity to other patients infected or colonized
with an MDRO. Higher patient density, from both higher
influx or longer length of patient stay, can increase direct
contact rates between patients which could increase the
probability of direct transmission of MDRO. In addition, because
patients shed bacteria into their local environments, patient
density can also increase contamination of the environment
www.healthcarehygienemagazine.com • IP&C Special Edition June 2020
25