under the microscope
By Rodney E. Rohde, PhD, MS, SM(ASCP)CM SVCM, MBCM, FACSc
Walking Through the Microscopic
Valley of Death
H
ave you ever stopped and thought about how fortunate
we are to live during this time? I am talking about
the advancement of healthcare in general and medical
procedures/devices in particular. Take a moment to consider
how an artificial hip or knee may have changed a loved one’s
life. What about the diagnostic medical devices utilized for
visualizing possible life-threatening conditions or disease?
Truly, I think we all probably take these wonders of medical
science for granted.
Globally, medical devices have prolonged our lives, as
well as improved the quality of life for millions. Most of
us probably think of replacement knees and hips, vascular
stents and pacemakers as representative of these engineering
marvels. Endoscopes and catheters, used for diagnostic
and therapeutic procedures, are categorized as medical
devices too since they are placed into the body and retain
their original form. To clarify, a needle that is inserted into
the body is classified as a medical device, but the solution
injected through that needle is specifically classified as
a pharmaceutical. Given that medical devices enter the
body, the need to be free of contamination is paramount
for patient safety.
Berkshire Corporation, via U.S. Food and Drug Admin-
istration (FDA) guidelines, explains contaminants and their
removal well. Prior to the introduction of the device into
the body (whether temporarily for diagnostic purposes
or permanently for therapeutic purposes), we want it to
be as free of contaminants as possible. Medical device
contaminants can include traces of lubricants, oils, and
other processing residues (e.g. polymers, adhesives), viables
(microorganisms), and non-viables, such as particles and
fibers. In the manufacturing process, medical devices are
packaged and then terminally sterilized as the last step.
The sterilization procedure does not remove contaminants;
it only ensures that any viables left on the device cannot
proliferate further–any residual surface contamination left
on the device before sterilization remains after the process
and can pose a risk to patient safety. Fortunately, simple
wiping techniques employed with proper wipers and solvents
prior to packaging and sterilization can produce a clean
medical device.
The FDA Center for Devices and Radiological Health
(CDRH) Microbiology and Infection Control states that with
the increased use of medical devices and their promise to
improve quality of life, preventing device-associated infection
is a top public health priority. Every medical device is prone
to microbial colonization and biofilm formation, resulting
inevitably in device failure and patient harm.
In addition, the association of colonized devices with
development of drug resistant organisms is a serious
8
and under-investigated area of importance. The Medical
Device Biofouling and Biofilms Research Program addresses
medical-device failure and patient harm caused by the
combined effects of biofouling, colonization, and biofilms.
Rather than study these phenomena as individual events,
the research uses sophisticated high-throughput microfluidic
approaches to assess how variables such as biofouling,
cleaning and material properties affect bacterial adhesion
and biofilm progression.
The group uses optical and electron microscopy, surface
plasmon resonance (SPR), and other biosensing and surface
analysis methods to study biomolecular interactions at the
interface of device, host and microorganism.
In laymen’s terms, this group is trying to determine the
best way(s) to understand not only what invisible inhabitants
are found in the microscopic valley of death (aka surfaces),
but how to best remove (clean and sterilize) them.
Some of the current research areas addressed include:
Bacterial interactions with soft medical device
materials (contact lenses, dermal fillers, ophthalmic
surgical devices
Development of better test methods and endpoint
measurements for antimicrobial device technologies
(wound dressings, catheters)
Biofilm specific diagnostics (optical coherence
tomography, biomarkers)
Detection of biofouling and biofilm on reprocessed
devices (endoscopes, surgical tools)
Influence of material, device design, roughness,
and presence of soil on cleanability
Performance testing of one-way valves Intended to
prevent cross-contamination and infections in patients
Reprocessing flexible endoscopes
Chemically defined clinically relevant test soils for
cleaning validation of reusable medical devices
While medical advances and devices have advanced the
health of civilization in ways we never fathomed, let us
not forget that the microorganisms have outpaced human
advancement every step of the way, including finding ways
to survive the microscopic valley and surfaces of arguably
every niche known.
Rodney E. Rohde, PhD, MS, SM(ASCP)CM SVCM, MBCM,
FACSc, serves as chair and professor of the Clinical Laboratory
Science Program at Texas State; associate director for the
Translational Health Research Initiative; as well as associate
dean for research in the College of Health Professions.
Follow him on Twitter @RodneyRohde / @TXST_CLS, or on
his website: http://rodneyerohde.wp.txstate.edu/
february 2020 • www.healthcarehygienemagazine.com