What’s to Blame?
Looking at the Sources
of Healthcare-Associated
Infections
By Frank Edward Myers, III, MA, CIC, FAPIC; and Kim Delahanty,
BSN, PHN, MBA, HCM, CIC, FAPIC
“W
It shouldn’t
come as a
surprise to us
that the most
likely cause
of a patient’s
Escherichia
coli (E. coli)
urinary tract
infection
(UTI) is
probably the
patient’s own
E. coli.
30
ash your hands!” and “The hand-
washing police are here!” are not
uncommon phrases for infection preventionists
to hear. And many of us have been taught that
“Handwashing is the single most effective way
to prevent the spread of infections.” A few years
ago, a famous infection preventionist, Marguerite
Jackson, researched that quote and found it most
likely first came from a lesson on food safety, not
healthcare-associated infections (HAIs). However,
Ignaz Semmelweis clearly demonstrated hand
hygiene was important in saving patient lives in
his hospital.
In the intervening years since Semmelweis, the
role of the environment has also been recognized
as a driver of infections. For some infections like
Legionella, the environment is the sole source
of the infection, but for organisms including
methicillin-resistant Staphylococcus aureus
(MRSA) the environment has also been implicated
in transmission to patients. As a response to
some studies, many products aimed at reducing
bacteria in the healthcare environment have
been developed.
Lastly, the patient’s own biome has been
recognized as the source of infections to the
patient. It shouldn’t come as a surprise to us that
the most likely cause of a patient’s Escherichia coli
(E. coli) urinary tract infection (UTI) is probably the
patient’s own E. coli.
While other sources of infections, such as zoo-
nosis, has been recognized as causing some HAIs,
there is no significant body that suggests these
other causes are a major driver of HAIs. Lastly, no
one studying the field of clinical epidemiology
and infection prevention believes any one of the
above sources causes all the HAIs, we know each
makes up a fraction of the HAI sources.
So, the question logically must be asked, what
is source of the majority or plurality of HAIs in the
developed world? The implications are enormous.
If the largest number of HAIs are associated with
the environment, then spending resources, —
human, supply and technological — to increase
the cleanliness of the room is imperative if we want
to improve our patients’ outcomes. Researchers
should invest aggressively in new technologies to
make that happen. If, alternatively, the greatest
source is the patient’s own biome, antimicrobial
stewardship, daily patient chlorhexidine gluconate
(CHG) bathing begin to be much more important
and resources dedicated to the environment have
a lower return on investment. Respectively, if it
is healthcare workers carrying the bacteria from
patient to patient, then hand hygiene technology
is imperative in lowering HAI numbers.
There has been no lack of articles implicating
the environment as a source of HAIs. A recent
analysis of 18 studies, though, found a mixed
bag of when the environment was likely the
source. To quote the authors, “Multiple studies
reported positive associations between infection
and exposure to roommates with influenza and
group A streptococcus, but no associations were
found for Clostridium difficile, methicillin-resistant
Staphylococcus aureus, Cryptosporidium parvum,
or Pseudomonas cepacia; findings were mixed for
vancomycin-resistant enterococci (VRE). Positive
associations were found between infection/coloni-
zation and exposure to rooms previously occupied
by patients with Pseudomonas aeruginosa and
Acinetobacter baumannii, but no associations
were found for resistant Gram-negative organisms;
findings were mixed for C. difficile, methicillin-re-
sistant S. aureus, and VRE.”
Some studies have found very strong associ-
ations and are frequently cited by those wishing
greater expenditure of resources on environmental
cleaning. However, while the findings using
traditional epidemiological techniques showed
significant associations between the environment
and acquisition of pathogens, what was important
was what percent of total cases could be attributed
to the environment compared to other sources.
Susan Huang, MD, the author of one of the papers,
even noted that although the adjusted odds ratio
march 2020 • www.healthcarehygienemagazine.com