| Sean
Seege checks a control panel as disinfecting
"robots," vaporize hydrogen peroxide to
fill sealed rooms and disinfect all sufaces at
Johns Hopkins hospital in Baltimore, Maryland, on
December 26, 2012. |
 |
BALTIMORE
— Even as epidemiologists worry about a shrinking
arsenal of antibiotics to fight potentially deadly
drug-resistant bacteria, researchers at Johns Hopkins
Hospital are betting on another weapon to prevent
infections: robots.
It
sounds more futuristic than it looks: The hospital uses
"robot" devices resembling portable
air-conditioning units to saturate the air in sealed
rooms with hydrogen peroxide, disinfecting all surfaces
before converting the potent mist into water vapor. The
technology has been used at the hospital more than 4,000
times over the past five years, with promising results.
Research
published Monday in Oxford University’s Clinical
Infectious Diseases journal explains that patients
admitted to rooms disinfected by the robots were nearly
two-thirds less likely to pick up drug-resistant
bacteria while in the hospital. The finding builds on a
growing understanding of the ways the so-called "superbug"
bacteria spread through hospital environments and how to
prevent infections.
Overuse
of antibiotics has caused some strains of bacteria to
develop immunity to common treatments, prompting doctors
to turn to more powerful antibiotics or older ones that
bacteria haven’t faced in decades. Meanwhile, public
health experts are using other methods to prevent the
bacteria from spreading and to stop infections,
particularly those acquired in hospitals and other
health care settings.
The
focus has been on health care workers themselves,
ensuring they don’t carry bacteria into operating
rooms and intensive-care units. But the Hopkins study,
like other types of technology being tested at hospitals
around the country, targets bacteria that survive on
surfaces, waiting to be transferred to sterile
dressings, instruments, and, ultimately, patients.
"If
you had talked to me maybe seven or eight years ago, we
would have discounted the role of the environment as
important in transmission," said Dr. Trish Perl,
senior epidemiologist for Johns Hopkins Health System
and one of the authors of the study. "The whole
concept of the role of the environment as important in
how these organisms are transmitted to patients and from
patient to patient has really emerged."
Hopkins
researchers spent 2 ½ years testing the robot
technology in 2007-2009. The hospital bought several
$40,000 pairs of the disinfecting robots from Bioquell
Inc. and hired the United Kingdom-based company to
operate them. The robots are in use in about 20 U.S.
hospitals and more around the world, with about 1,000
patient rooms cleaned every month, said Mike Duclos, a
Bioquell technician who helped perform the Hopkins
study.
In
each set, one robot fills a hospital room or unit with
hydrogen peroxide mist; once the air has been saturated
with the concentrated chemical, a second robot releases
a catalyst that reacts with the hydrogen peroxide to
turn it into water. The cleaning solution is 35 percent
hydrogen peroxide, compared with the 5 percent solution
sold in drugstores, making it toxic to humans but
particularly effective at killing bacteria.
Bioquell
crews seal up heating and cooling vents, doorways and
cracks to keep the chemical in and to ensure it can
saturate the room, a process that can take from an hour
and a half to three hours, depending on the humidity
that day. Because the mist is produced on a microscopic
level, it doesn’t leave any visible moisture behind
and is safe to use on electronics.
The
researchers tested the technology’s effectiveness by
collecting data on more than 8,800 patients at the
hospital. Some were excluded because of a known history
with a multidrug-resistant organism, while the rest were
monitored in rooms where previous patients had been
found to carry any of several types of such organisms.
In some cases, the robots were used to disinfect the
room after normal cleaning was performed.
Researchers
found that one-third as many patients acquired
Staphylococcus aureus bacteria, also known as MRSA, in
rooms that the robots had disinfected as in rooms they
had not. When testing for a different type of bacteria,
vancomycin-resistant enterococci, nearly seven times as
many patients acquired the bacteria in rooms that had
not been treated by the robots.
Drug-resistant
bacteria have caused high-profile scares in recent
years, including an outbreak that killed a seventh
person at the National Institutes of Health Clinical
Center in Bethesda, Md., in September. In that case,
officials found that simply following CDC guidelines was
not enough to rid the environment of the bacteria, and
workers went far beyond the regulations to rip out
plumbing found to be harboring the organisms.
Doctors
and scientists have worked to fight the bacteria once
they cause infections, with limited effectiveness, and
potential backfires.
"We’re
running out of antibiotics to use," Dr. Anthony
Harris, a professor of epidemiology, public health and
medicine at the University of Maryland School of
Medicine, said in October. "The problem arising in
many hospitals is this paradigm of giving broad agents
to the patient who’s right in front of you. It works
in some instances, but in others, the group or public
health impact is more adverse."
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As
an alternative, technologies that focus on killing
bacteria in the hospital environment have become more
widespread. In one example, robots emit ultraviolet
light to kill bacteria on hospital surfaces at
Chesapeake Regional Medical Center in Chesapeake, Va.,
and eight other facilities under a $2 million CDC grant
awarded to Duke University. Other technologies being
developed use hydrogen peroxide in other ways, or xenon
gas, Perl said.
Proving
a technology’s effectiveness is crucial in addressing
the problem, and means a lot of potential business for
companies such as Bioquell. Its robots are also used in
laboratory settings, for food and drug safety, and as
defense against chemical or biological weapons, said
Sean Seege, a Bioquell technician.
"It’s
becoming more and more difficult" to fight
drug-resistant bacterial infections, Seege said.
"The idea here is to prevent them."
The
prospect of using the technology more widely has
limitations, researchers said. The process can sometimes
be impractical, since it can take several hours. Still,
it only had to be skipped 4 percent of the time during
the study because of an urgent need for a room, they
wrote in the study.
For
now, Hopkins continues to use the robots in
high-priority areas like intensive-care units, Perl
said. But officials plan to continue to build on the
research.
"We
need to do further work," Perl said. "We have
to figure out how to best use them."
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