A Johns Hopkins study of adult patients admitted to
The Johns Hopkins Hospital showed that patients who resided
in nursing homes or other kinds of long-term
care-facilities at any time within the previous six months
were far more likely than other adult patients to carry or
be infected with a drug-resistant superbug.
The study, conducted over a four-month period in 2006,
was intended to grasp the extent of one of the lesser known
hospital superbugs — multidrug-resistant
Acinetobacter, or MDR-ACIN — and control its spread
among the hospital's most vulnerable adult patients. More
than 1,600 were screened within 24 hours of admission to
any one of five intensive care units where previous
infections had been recorded.
Results showed that patients who had been in nursing
homes, either admitted to Johns Hopkins directly from a
long-term care facility or transferred from home or another
community hospital, were 12 times more likely than other
patients to be carriers of the bacterium. Rates were even
higher, 22 times more likely, among those patients who were
wheelchair- or bed-bound because their legs were
paralyzed.
As a result of the study, The Johns Hopkins Hospital
will begin this summer to test all patients who have spent
time in a nursing home, looking for drug-resistant bacteria
at the outset of their hospital admission while also using
isolation precautions until their test results are
known.
Unless these test results are negative for superbugs,
patients will be treated as potential carriers. They will
receive care only in designated confined treatment spaces
or separate rooms. During treatments, hospital staff will
be required to wear disposable gloves, masks and gowns, and
to clean equipment and furniture with strong
disinfectants.
The change in procedures related to superbug infection
control is designed to prevent spread of highly contagious
bacteria that are resistant to many antibiotics and
represents a step up from the current practice in which
adult patients in intensive care are screened on admission
for the presence of antibiotic-resistant germs but are
placed in isolation only if tests are positive.
What most surprised researchers was that a majority of
the MDR-ACIN-colonized patients, who ranged in age from 19
to 74, also carried high rates of three other, more common
superbugs. Sixty-two percent had methicillin-resistant
Staphylococcus aureus, 77 percent had vancomycin-resistant
enterococcus, and 39 percent had extended-spectrum
beta-lactamase gram-negative bacteria.
Hospital epidemiologists in charge of patient safety
say that their decision to test and isolate such
individuals is recognition that safeguards must be tailored
to high-risk patient populations in a given community.
"Our best safeguard is to tailor Hopkins' screening
and isolation policies to the types of infection in our
local population," said Trish Perl, study senior author and
hospital epidemiologist. "Forewarned is forearmed, so by
identifying this group of patients as more susceptible to
carrying these bacteria, we are better prepared to thwart
further spread through early detection, isolation and
effective treatment."
The immediate danger to patients from superbugs is
that they can lead to potentially dangerous bloodstream
infections, says Perl, a professor of
medicine and
pathology at the Johns Hopkins School of Medicine. Perl
is past president of the Society of Health Care
Epidemiology and presented last week at the organization's
annual meeting in Baltimore. More than 300 studies and
abstracts from researchers around the world were discussed
at the four-day conference, which focused on prevention and
treatment of infectious diseases in the health care
environment.
The researchers' findings, presented April 16,
represent the first large-scale survey of Johns Hopkins'
adult patients to identify those most at risk of harboring
MDR-ACIN, or those at risk of infecting other patients and
staff.
No explanation for the high rates was clearly evident
from the study, but researchers say the severe underlying
illnesses and weakened immune systems in many of the
nursing home residents, especially those unable to walk on
their own, make these patients prime targets for all kinds
of bacteria.
Lisa Maragakis, the hospital epidemiologist who led
the investigation, said, "Our results dramatically
illustrate how widespread these drug-resistant bacteria
have become among health care facilities in just the last
decade. This is only going to complicate our efforts to get
a grip on the problem, and it is going to place added
pressure on all hospitals and other health care facilities
to increase and fine-tune their surveillance and control
measures."
Maragakis, an assistant professor in the School of
Medicine, points out that of the most widely available
drugs used to fight Acinetobacter, frequently only one,
Colistin (polymyxin E), is effective against MDR-ACIN. And
she says other hospitals have even encountered MDR-ACIN
that is also resistant to Colistin, leaving no available
treatment options.
All patients infected with MDR-ACIN are put on
antibiotic therapy to rid their body of the bacteria.
Patients who are carriers but are not infected do not need
this treatment. However, staff must follow the strict
isolation precautions for patient care.
Maragakis says that hospital outbreaks of MDR-ACIN
have become a widespread problem in the last decade. In
2006, the Joint Commission on Accreditation of Healthcare
Organizations (now known simply as the Joint Commission)
estimated that 70 percent of the bacteria that cause
infections for 2 million hospitalized Americans each year
are resistant to at least one of the drugs most commonly
used to treat them.
Researchers say their next steps are to monitor
colonization and infection rates over the next year in
patients from nursing homes and to identify any other local
populations who also may be at higher risk, such as
veterans of the war in Iraq, where MDR-ACIN is endemic.
They also plan to evaluate bathing practices, such as
chlorohexidine washes that destroy any germs on the body
surface, to see if they are effective at preventing
bacterial spread.
Funding for the study was provided by the U.S. Centers
for Disease Control and Prevention. Other Johns Hopkins
investigators involved in this study were Margaret Gifford,
Kathleen Speck, Tracy Ross and Karen Carroll.