Cover story

CE
CONTINUING EDUCATION
To earn CEUs, see current test at
www.mlo-online.com under the CE Tests tab.
LEARNING OBJECTIVES
Upon completion of this article, the
reader will be able to:
- Describe the evolution of automated molecular diagnostics with
regard to the spread of infectious diseases.
- List three major reasons to improve time-to-results through
molecular testing.
- Recognize the importance of antibiotic stewardship and what it means
to patient safety.
- Describe how effective communication between labs and physicians
affects antibiotic stewardship.
- Discuss new technology and surveillance impacts on MRSA statistics
in hospitals.
MRSA: a crisis that
touches you
How automated molecular dx will
help relieve the time and cost crises facing hospital labs
By Ryan Ashton
If time is money,
as the saying goes, then hospital laboratories and the managers that oversee
them are in crisis. They face ever-mounting pressure from clinical
departments to deliver patient test results faster — and around the clock —
in order to shorten time to treatment, improve clinical outcomes, and reduce
skyrocketing hospitalization costs.1
At the same time, hospital administrators often
view laboratories as a cost center ripe for budget slashing. In the face
of a national laboratory-workforce shortage,2 lab managers
working with shrinking budgets are finding it difficult to attract and
retain personnel trained to carry out the labor-intensive molecular
diagnostic tests demanded by today’s healthcare system. Adequately
staffing a single shift is difficult; having such skilled lab
professionals available on all three shifts is unheard of, even with the
growing demand for on-demand, round-the-clock test results. Further,
high reagent costs coupled with low reimbursement rates result, at best,
in razor-thin margins on common tests.
A key example of the critical nature of time
to results is in the diagnosis and treatment of hospital-acquired
infections.
These issues do not create simply headaches for
lab managers — they represent a serious and growing systemic problem in
healthcare, both nationally and globally.3 Industry groups
have proposed multipronged solutions for attracting young talent to the
field, improving reimbursement, and, generally, enhancing the awareness
of the laboratory-diagnostics field as essential and invaluable to
healthcare. A necessary part of any long-term solution, however, will
have to include the simplification and automation of molecular
diagnostic testing.
The evolution of automated molecular diagnostics
The demand for molecular diagnostic tests is
growing rapidly, fueled especially by the increasing need for hospitals
to track and control4 the spread of infectious diseases, such
as methicillin-resistant Staphylococcus aureus (MRSA), group B
streptococcus (GBS), Clostridium difficile, and
vancomycin-resistant
enterococcus (VRE). The current gold-standard technique in
molecular diagnostics is polymerase chain reaction (PCR) with real-time
fluorescence-based detection. Although an exquisitely sensitive method
for detection of nucleic acids in very low copy numbers, PCR is highly
complex and labor intensive, and easily susceptible to
cross-contamination as well as inhibition by sample impurities. For
these reasons, molecular diagnostic tests generally are rated as "highly
complex" by the standards of the Clinical Lab Improvement Amendments.
They, therefore, must be performed by technicians with special training
and certifications, typically staffed during the day shift at most
hospital laboratories, leaving at least 16 hours per day during which
these tests cannot be performed.
In recent years, a number of companies have developed
small, automated bench-top analyzers with low-cost, disposable cartridges
for performing, on demand, certain routine lab tests, such as hematocrit,
blood lipid, creatinine and electrolyte levels, blood coagulation times, and
others. But these technologies are not yet capable of performing
PCR-equivalent molecular diagnostics. Now on the horizon is a new generation
of automated laboratory analyzers that will meet the growing demand for
moderately complex molecular diagnostic tests. They will be able to reduce
the complexity of these tests to the point where they can be run by less
experienced laboratorians. Although the first such technologies are being
rolled out with a relatively high per-test price, these newer products will
finally fulfill the need for simple molecular diagnostics at a cost that
allows laboratories to realize a reasonable margin on their efforts.
The ideal automated molecular diagnostics system will
offer results that are equivalent or superior in sensitivity to current PCR
tests — but at a nominal price and with dramatically reduced need for
handling and sample preparation compared to PCR techniques. A laboratory
technician should simply be able to load a few microliters of minimally
prepared sample (e.g., whole or heparinized blood, buffer-suspended swab, or
culture samples, and so on) into an inexpensive, disposable test cartridge,
insert the cartridge into the analyzer, push "start," and walk away with the
expectation of seeing a clear result in about an hour.
Improved time to results has far-reaching implications
Such a drastic simplification of the molecular
testing process will have far-reaching implications for laboratories and the
patients, physicians, and hospitals they serve:
Streamline lab processes and reduce labor
overhead. The most immediate and obvious benefit of automated
molecular diagnostics will be in relieving the labor squeeze felt by most
labs today. While the typical moderately complex molecular diagnostic test
is very labor intensive and requires skilled handling, automation at this
level enables less experienced lab pros to produce the same results in far
less time. The laboratory personnel structure can be reshaped to reflect a
small number of specialized clinical laboratory scientists, focused on
hands-on, highly complex tests, supported by a base of round-the-clock
personnel running the automated molecular diagnostics.
Reduce hospital costs by quickly identifying
infectious diseases. The time that elapses between when a patient
presents with symptoms and when test results become available can be a
significant factor in how treatment decisions are made and, ultimately, in
clinical outcomes. A key example of the critical nature of time to results
is in the diagnosis and treatment of hospital-acquired infections.
Currently, confirmation of suspected MRSA in a patient presenting with fever
of non-specific origin takes approximately four days and includes several
successive steps: a 48-hour culture from drawn blood; an assay to detect
Gram-positive cocci in clusters (GPCC); bacterial-strain identification
testing; and finally, culturing to determine an antibiotic-resistance
profile. In the meantime, hospitalization costs for the infected patient
accumulate. A study of hospital-acquired infections done by the state of
Pennsylvania and published in 2006 showed insurers paid an average of
$53,915 for hospitalization of an infected patient compared to $8,311 for
patients without infection.1
Increasingly, payers are refusing to reimburse for the added cost of
infections acquired during hospital stays, shifting that financial burden to
the hospital.
While available, manually performed molecular
diagnostic tests for MRSA and many other infectious diseases are
prohibitively expensive to run on demand because the controls and other
reagents are perishable and extremely costly. They, therefore, must be
batched, which is not practical in a time-sensitive situation.
Automated molecular diagnostics are beginning to
change this scenario, reducing the time to diagnosis, treatment, and cure,
and, potentially, saving thousands of dollars in hospitalization costs.5
In the MRSA example, an automated molecular diagnostic test could be used to
determine the exact strain and antibiotic-resistance profile directly from
the patient’s GPCC-positive blood culture. The test could be designed such
that time to results would be 40 to 60 minutes, with minimal handling by a
laboratory technician, at very low cost, and run on demand during any shift,
day or night.
Now on the horizon is a new generation of automated laboratory
analyzers that will meet the growing demand for moderately complex
molecular diagnostic tests.
Improve treatment decisions and patient
outcomes with fast, on-demand test results. Another example of a
particularly time-sensitive test that would benefit from automation is that
for
Streptococcus agalactiae or group B streptococcus. GBS is the leading
cause of newborn sepsis and meningitis in the United States, with mortality
rates of 5% or higher,6 and can be transmitted from a colonized,
asymptomatic mother to her infant during childbirth. Fortunately, antibiotic
intervention immediately pre-partum can substantially reduce the risk to the
newborn.
The current test for GBS involves a 48- to 72-hour
culture, which makes it impractical for testing a woman in active labor
whose GBS status is unknown or uncertain. The result is a high incidence of
antibiotic over-prescription, at a time when the medical community is making
every effort to reduce unnecessary antibiotic use in order to fight the rise
of drug-resistant pathogens. A molecular diagnostic test could potentially
improve the time to results; but if it is moderately complex and can only be
performed by a day-shift, skilled laboratorian, the same problems apply. A
low-cost, automated molecular diagnostic solution could be carried out by
technicians at any time, day or night, with results available less than an
hour after a woman presents at Labor and Delivery.
Automated molecular diagnostics are beginning to change this
scenario, reducing the time to diagnosis, treatment and cure, and,
potentially, saving thousands of dollars in hospitalization costs.
The time has come for automated molecular solutions
Although molecular diagnostic tests represent a vast
improvement over culturing protocols for identifying infectious-disease
organisms and other nucleic-acid-based targets, they can still be time
consuming, labor intensive, and expensive, and contribute to the clinical
laboratories staffing problems today. With the introduction of automated
molecular diagnostic solutions, the time has finally come for lab managers,
hospitals, healthcare professionals, and patients to benefit from the
molecular discoveries of the past decade. The race against disease is really
a race against time, and automation is providing a much-needed head start.
Ryan Ashton
is the president and CEO of Great Basin Scientific in Salt Lake City, UT.
References
- Report by the Pennsylvania Health Care Cost Containment Council.
Hospital-Acquired Infections in Pennsylvania, 2008.
http://www.phc4.org .
Accessed January 5, 2009.
- Washington G-2 Reports. Alarm Sounded Again Over Shrinking Supply of
Lab Personnel. National Intelligence Report.
2008;29:4-6.
- American Society for Clinical Pathology. Shortage. Critical
Values Newsletter, 2008;1(4).
- Berens MJ, Armstrong K. MRSA: Patients revolt against hospital
secrecy. Seattle Times. November 18, 2008.
- Cunningham R, Jenks P, Northwood J, et al. Effect on MRSA
transmission of rapid PCR testing of patients admitted to critical care.
J Hosp Infect. 2007; 65:24-28.
- Bergeron MG, Ke D, Menard C, et al. Rapid detection of group B
streptococci in pregnant women at delivery. N Engl J Med. 2000;
343:175-179.
Plus
Labs take new role in antibiotic stewardship, championing improved
diagnoses, guiding therapy, saving lives, and cutting costs
By Joe Romano
Optimizing
antibiotic therapy and antibiotic stewardship is a mantra often chanted,
yet together they seldom get the necessary recognition as a common
denominator that mutually impacts departments hospital-wide.
Unfortunately, laboratories are not always typically perceived as
central actors who take the leading role to drive the overall
success of a hospital enterprise by facilitating a key paradigm shift in
antibiotic management. As a result, the inappropriate use of
antimicrobial agents in the form of under- or over-treatment of
infections is a common problem; and optimizing antibiotic therapy for
patients continues to pose a major challenge.1
What is the problem, and how did we get here?
Unnecessary use or overuse of antibiotics is
associated with significant increases in healthcare costs, hospital length
of stay, and the development of pathogens that are resistant to many types
of antibiotic therapy.2-4 The failure to promptly deliver
or quickly administer antibiotic therapy to patients with potentially
life-threatening infections is associated with increased morbidity and
mortality.5-8
To exacerbate the problem, hospital physicians are
confronted with patients every day who potentially have life-threatening
bloodstream infections. As a result, clinicians are typically forced to
decide which antibiotic, if any, should be administered to the patient. In
order to appropriately cover a wide variety of increasingly resistant
pathogens, broad-spectrum antibiotic therapy is frequently administered when
blood-culture results are reported as positive and an infection is
suspected.
Moreover, bacteremia is also a leading cause of
infection among hospitalized patients. Staphylococci are the most frequent
bloodstream isolates, accounting for more than 50 of positive bloodstream
cultures.9-10
Although coagulase negative staphylococci (CoNS) are commonly isolated from
blood, only a minority of such cultures represent true infection.11
Conversely, blood cultures growing Staphylococcus aureus almost
invariably signify true bacteremia and may be associated with severe
complications, including foci of secondary infection at distant sites such
as bones, joints, endovascular structures, and the central nervous system.
Furthermore, a majority of nosocomial S aureus bloodstream infections
are now caused by MRSA strains.10
Delay in the institution of appropriate therapy in
patients with S aureus sepsis may lead to catastrophic complications,
including bacterial seeding of deep tissues; such delays are associated with
increased hospital costs, length of hospitalization, and death.8,12,13
As more clinical and microbiological data becomes available, antimicrobial
therapy is narrowed or discontinued, yet — in the interim — antibiotic
stewardship yields to the practical and immediate need to essentially treat
the patient and administer a broad-spectrum of drugs before a proper
diagnosis is secured.
New approaches to improve antibiotic stewardship
Antibiotic administration practices have become a
major focus of antibiotic-stewardship quality-improvement programs at many
hospitals. The pressures to provide prompt and effective antibiotic therapy
to patients most likely to benefit from it while minimizing the unnecessary
use of antibiotics have spurred alternative approaches to improve antibiotic
stewardship.
One target of antibiotic-reduction efforts has been
the over-utilization of broad anti-staphylococcal agents, particularly
vancomycin. These antibiotics are generally started when a Gram-positive
infection is suspected on clinical grounds or when bacterial stain and/or
cultures show Gram-positive cocci. An important diagnostic and therapeutic
branch point occurs when clinicians try to differentiate true staphylococcal
bacteremia from blood-culture contamination. Physicians often prescribe an
anti-staphylococcal antibiotic for patients with blood cultures growing
Gram-positive cocci in clusters.
When using traditional laboratory techniques,
identification of the organism as S aureus, or the more benign CoNS
may take up to 48 hours. Earlier differentiation between S aureus and
CoNS facilitates implementation of more targeted antibiotic therapy and
improved overall antibiotic-stewardship programs. To truly change and
improve these programs, however, faster and more rapid diagnostics must be
integrated into laboratories — and their results must be more expeditiously
delivered to attending physicians — to facilitate this paradigm shift.
Enabling the paradigm shift
To address this need, clinical laboratories and
microbiologists are frequently relying on more rapid diagnostic tests to
detect S aureus and improve antibiotic stewardship. Given the time
and resource constraints facing microbiologists, very rapid methods for the
detection of S aureus-specific nucleic-acid sequences, such as
peptide nucleic-acid fluorescence in situ hybridization (PNA FISH),
are used. PNA FISH tests enable microbiology labs to provide rapid and
accurate identification of bloodstream pathogens directly from positive
blood cultures in hours instead of days, providing the following benefits:
- rapidly differentiate S aureus from CoNS in bloodstream
isolates;
- allow faster diagnoses and more accurate antibiotic-therapy
selection; and
- guide dramatic improvements in antibiotic stewardship that results
in improved patient outcomes
and healthcare-resource
utilization.
Antibiotic stewardship also depends on improved communication between
labs, treating clinicians
The communication of
laboratory results to the treating clinician closes the loop initiated at
the time of blood-culture draw. In a study of 509 episodes of clinically
significant bloodstream infections, therapeutic interventions typically
occurred at the time of phlebotomy and after notification of Gram-stain
results by telephone.14 The clinical value of rapid diagnostic
tests depends on an expeditious reporting of the results to the treating
clinician.15 The rapid reporting of results, coupled with
education regarding the implications of S aureus
vs. CoNS, can significantly affect resource utilization and clinical
outcomes.
Forrest, et al, reported that in the context of an
antimicrobial utilization team, the use of a rapid diagnostic technique (PNA
FISH) to identify S aureus was associated with a significant
reduction in median length of hospital stay from six to four days (P<0.05;
95 confidence interval [CI], 0.95-1.87), a trend toward less use of
vancomycin, and a decrease in associated hospital costs of approximately
$4,000 per patient.16 Ly, et al, demonstrated that the rapid
reporting of S aureus PNA FISH results was associated with a
reduction in overall mortality (8 vs. 17; P=0.05) and in duration of
antibiotic use in patients with CoNS (median, 2.5 days; P=0.01).17
These studies suggest that an approach whereby
accurate microbiology data is rapidly generated, disseminated, interpreted,
and acted upon by a highly integrated healthcare team can leverage the
combination of rapid diagnostics and antibiotic stewardship to guide
therapy, enhance appropriate use of antibiotics, and improve patient
outcomes.
The optimization of antibiotic therapy in
hospitalized patients coupled with the need for improved antibiotic
stewardship will continue to be a major challenge that new assays and
procedures are beginning to meet in the laboratory.18 The coming
years are expected to bring further advances in the rapid detection of
bloodstream microbes and the identification of resistant strains. Optimizing
the effects of these advances will require the delivery of results from the
diagnostic laboratory to clinicians in a more timely fashion. Coupling
advances in diagnostic techniques with current and emerging communication
technology will facilitate this process.
As data accumulate regarding the effect on clinical
outcomes of rapid diagnostics and clinician notification, these strategies
are expected to replace the slower, traditional methods. To truly change and
improve these programs, however, faster and more rapid diagnostics must be
integrated in laboratories, and test results must be more expeditiously
delivered to attending physicians.
Joe Romano
is a consultant for AdvanDx (www.AdvanDx.com),
located in Woburn, MA, a company that develops simple and easy-to-use
diagnostic tests based on molecular technology platforms that utilize
genomic information to identify specific gene or species-specific sequences
in bacteria and yeast.
References
- Dellit TH, Owens RC, McGowan JE Jr, et al. Infectious Diseases
Society of America and the Society for Healthcare Epidemiology of
America guidelines for developing an institutional program to enhance
antimicrobial stewardship. Clin Infect Dis. 2007;44(2):159-177.
- McGowan JE Jr. Antimicrobial resistance in hospital organisms and
its relation to antibiotic use. Rev Infect Dis.
1983;5(6):1033-1048.
- Cosgrove SE, Sakoulas G, Perencevich EN, et al. Comparison of
mortality associated with methicillin-resistant and
methicillin-susceptible
Staphylococcus aureus
bacteremia: a meta-analysis. Clin Infect Dis. 2003;36(1):53-59.
- Cosgrove SE, Qi Y, Kaye KS, et al. The impact of methicillin
resistance in
Staphylococcus aureus
bacteremia on patient outcomes: mortality, length of stay, and hospital
charges. Infect Control Hosp Epidemiol. 2005;26(2):166-174.
- Houck PM, Bratzler DW. Administration of first hospital antibiotics
for community-acquired pneumonia: does timeliness affect outcomes?
Curr Opin Infect Dis. 2005;18(2):151-156.
- Meehan TP, Fine MJ, Krumholz HM, et al. Quality of care, process,
and outcomes in elderly patients with pneumonia. JAMA.1997;278(23):2080-2084.
- Leibovici L, Shraga I, Drucker M, et al. The benefit of appropriate
empirical antibiotic treatment in patients with bloodstream infection.
J Intern Med. 1998;244(5):379-386.
- Ibrahim EH, Sherman G, Ward S, Fet al. The influence of inadequate
antimicrobial treatment of bloodstream infections on patient outcomes in
the ICU setting. Chest. 2000;118(1):146-155.
- Scheckler WE, Bobula JA, Beamsley MB, et al. Bloodstream infections
in a community hospital: a 25-year follow-up.
Infect Control Hosp Epidemiol. 2003;24(12):936-941.
- Wisplinghoff H, Bischoff T, Tallent SM, Seifert H, Wenzel RP, Edmond
MB. Nosocomial bloodstream infections in US hospitals: analysis of
24,179 cases from a prospective nationwide surveillance study. Clin
Infect Dis. 2004;39(3):309-317.
- Beekmann SE, Diekema DJ, Doern GV. Determining the clinical
significance of coagulase-negative staphylococci isolated from blood
cultures. Infect Control Hosp Epidemiol. 2005;26(6):559-566.
- Schramm GE, Johnson JA, Doherty JA, et al. Methicillin-resistant
Staphylococcus aureus sterile-site infection: the importance of
appropriate initial antimicrobial treatment. Crit Care Med.
2006;34(8):2069-2074.
- Shorr AF, Micek ST, Kollef MH. Inappropriate therapy for
methicillin-resistant
Staphylococcus aureus: resource utilization and cost implications.
Crit Care Med. 2008;36(8):2335-2340.
- Munson EL, Diekema DJ, Beekmann SE, et al. Detection and treatment
of bloodstream infection: laboratory reporting and antimicrobial
management. J Clin Microbiol. 2003;41(1):495-497.
- Doern GV. Clinically expedient reporting of rapid diagnostic test
information. Diagn Microbiol Infect Dis. 1986;4(3
suppl):151S-156S.
- Forrest GN, Mehta S, Weekes E, et al. Impact of rapid in situ
hybridization testing on coagulase negative staphylococci-positive blood
cultures. J Antimicrob Chemother. 2006;58(1):154-158.
- Ly TV, Travison TG, Castillo RC, et al, LEAP Study Group. Impact
upon clinical outcomes of translation of PNA FISH-generated laboratory
data from the clinical microbiology bench to bedside in real time.
Ther Clin Risk Manag. 2008;4(3):637-640.
- Tenover FC. Rapid detection and identification of bacterial
pathogens using novel molecular technologies: infection control and
beyond. Clin Infect Dis. 2007;44(3):418-423.
And
Implementing a real-time PCR assay for rapid surveillance of MRSA
By David Persing, MD, PhD, and Ellen Jo
Baron, PhD
Most healthcare
institutions in the United States have been watching an ominous trend of
escalating proportions of methicillin-resistant
Staphylococcus aureus infections. According to the Centers for
Disease Control and Prevention, more people in the United States die
annually from MRSA (estimated 18,650 deaths) than from AIDS (roughly
16,000 deaths).1
In addition to loss of life, MRSA costs the Amercan
healthcare system over $ 2.5 billion in non-reimbursable costs.2
In terms of the healthcare setting, MRSA infection rates have increased over
the past three decades — in 1974, MRSA accounted for 2% of staph infections;
in 2004 the number rose to 63%.3
In healthcare environments, MRSA is spread from
patients who already have an MRSA infection or who are colonized with the
bacterium but do not have any symptoms. The harmful pathogen is passed to
other patients through hand-to-hand contact or by touching contaminated
surfaces such as bed rails
or telephones.
Many institutions have begun selective testing of
some patients believed to be at higher risk. Several commercial chromogenic
agar plates have been developed to culture nasal swabs for active
surveillance of MRSA. Even with the most rapid culture turnaround time,
however, results from cultures are not available for at least 18 hours after
inoculation of the medium. Such results could reach the unit more than a day
after a colonized patient has been sharing a room with a non-colonized
patient.
Moving the non-colonized patient into another room at
this point can be a social and public-relations nightmare for patients,
their families, and hospital administrators. The alternative, instituting
barrier precautions pre-emptively on all patients until their MRSA status is
known, is costly and problematic; despite the success of this strategy in
controlling MRSA in Denmark and the Netherlands, not all healthcare
institutions in the United States have that capacity.
Selective testing of patients based on some risk
assessment has been shown to detect less than 85% of the colonized patients
in a hospital4; and the elaborate admission interview required to
determine who might be at risk is counterproductive, disliked by nursing
staff, and slows down admissions. Even less effective is passive
surveillance, in which MRSA carrying patients are discovered and isolated
only if cultures sent to the clinical laboratory yield MRSA. This approach
fails to identify 70% of truly colonized patients.5
As MRSA outbreaks are widely reported in the news
media, the public’s fears are increasing, putting pressure on policymakers
to address the issue. Already five states have enacted legislation mandating
surveillance of MRSA for high-risk units in a hospital, and 31 states have
reporting requirements.
Many hospitals are now implementing systems that use
fully integrated real-time PCR technology, in most cases for the purpose of
implementing rapid MRSA surveillance as part of their overall
infection-control program. Major advantages of such a system is a MRSA test
available in cartridge form with (1) its ability to process and deliver
results in less than one hour, enabling physicians to take the appropriate
precautions before the pathogen has the opportunity to spread, and (2) its
moderate complexity, allowing a non-clinical laboratory scientist to perform
the test.
The new technology combines on-board sample
preparation with real-time PCR amplification and detection functions for
fully integrated and automated nucleic-acid analysis. Training to use a
moderate complexity test is easy, and less experienced workers can perform
such tests with minimal hands-on time. With a random-access system, a new
sample can be added at any time. In many laboratories, the combination of
ease of use and random access translates into 24/7 access to MRSA results.
Nearly 450 U.S. hospitals (and over 900 worldwide) to
date have chosen to deploy this technology, and laboratory technicians and
technologists have voiced their satisfaction with the simplicity of the
system’s workflow and its proven results.
Leaders at sites that have implemented the MRSA assay
have been able to reduce infection rates and cut healthcare-associated costs
while improving patient care.
How are hospitals using rapid testing technology?
"The patients with the highest risk of MRSA infection
are those who undergo invasive surgeries making it a serious concern for our
orthopedic hospital" says Maureen Spencer, RN, MEd, CIC infection-control
manager at New England Baptist Hospital in Boston. "Following invasive
orthopedic surgical procedures, post-operative surgical wounds are
vulnerable to infection — particularly bone infections which are among the
toughest to treat.
"We were one of the first sites in the United States
to implement a pre-screening program for all surgical patients for MRSA.
When selecting a pre-screening program, time to result is a huge factor. It
is critical that patients know their MRSA status before they leave their
surgical consult in order to initiate a topical decolonization protocol and
allow the surgeon to adjust the surgical antibiotic prophylaxis. Using the
MRSA assay and the system, we proactively screen all surgical patients for
MRSA at least two weeks prior to their procedure. If they are colonized with
staph, doctors place the patients on a five-day decolonization protocol and
conduct a second screening for MRSA before admission to the hospital for
surgery. The goal is to reduce the introduction of MRSA into the hospital by
ensuring patients are MRSA-free before they are admitted.
"Our data is showing that pre-screening surgical
patients for MRSA lowers infection rates, creating a win-win situation for
the hospital and patients. Since implementing the first PCR test in July of
2006 and moving to the MRSA test in early 2007, our hospital saw MRSA
infection rates drop nearly 60%; from 0.46% to 0.18% in 2007 and decreasing
further to 0.11% in 2008. This has helped the hospital decrease its
orthopedic surgery hospital-acquired infection rates to 0.3% which is five
times lower than the average national rate of 1.5%."
In Wooster, OH, Gail Woosley, manager of Lab Services
for Wooster Community Hospital says, "The goal of our infection-control
program is to lower healthcare-acquired infection rates and improve patient
care by delivering physicians the test results they need as quickly as
possible. In my 33 years in the field, it is not often that I am impressed
by some of the new technology being made available, but this system really
impressed me. Relative to other lab equipment, the new system technology is
affordable, even for a small institution. If you have a device that can save
you money in terms of patient time in the hospital, supplies used during
their hospital stay, and the health of the patient, its value is not
measurable.
"We find that technology to be very useful in three
patient population groups.
- The first group includes individuals that are having any type of
surgery where a foreign body will
remain within the patient
such as joint replacement or hernia repairs.
- Our second and largest group includes those coming to us from
another healthcare facility.
These people are screened upon
admission and then placed in the appropriate room with the
appropriate precautions. The rapid turnaround time allows us to identify
which patients are
colonized, enabling us to place that
at-risk patient in isolation in order to curb the spread of the
infection. Traditional turnaround time prevented us from taking
these measures which were
necessary because we still have semiprivate rooms in our
institution.
- Our final group includes those individuals that have been admitted
patients in our facility but
return for re-admission. If this
happens within 45 days from discharge, we test upon
readmission."
In Stockton, CA, Richard Wong, administrative
director of Pathology and Clinical Laboratory for Dameron Hospital, says,
"We have been at the forefront in the San Joaquin Valley with regard to
active surveillance on multidrug-resistant organisms since the 1987
implementation of its first screening program.
"Technology has allowed us to expand and improve on
our infection- control methods as the nationwide threat of hospital-acquired
infections grows. The MRSA test delivers the fastest time to result
available today, making it an ideal technology for our critical initiative,
allowing us to reduce hospital-acquired infection rates and provide the
highest standards of patient safety.
On average, our hospital runs about 480 MRSA tests
per month with plans to increase as we move towards universal screening of
all patients who enter the site. Of importance, we have found the MRSA assay
is 100% sensitive compared to culture-based tests."
More recently tests approved for the system we use
include a combined test for S aureus (usually methicillin sensitive)
and MRSA in blood cultures from patients with suspected sepsis, and a
similar test for direct detection of both organisms in skin and soft-tissue
infections. Both tests deliver results in less than one hour and their
results can be used in real-time to guide optimal treatment or management
decisions. Other tests in development that are relevant to infection control
include a test for VRE,
Clostridium difficile, and multidrug-resistant tuberculosis. It is
becoming increasingly clear that the medical value of rapidly available,
actionable results provided by the new technology can be an important ally
in the "search-and-destroy" strategy being adopted by more and more
hospitals.
David Persing,
MD, PhD, is the executive VP and chief medical and technology officer
for Cepheid.
Ellen Jo Baron, PhD, is director of Medical Affairs for Cepheid. The
systems and tests for which Cepheid is well-known are its GeneXpert System
and its accompanying MRSA/S Aureus test.
References
- Klevens RM, Morrison MA, Nadle J, et al. Invasive
Methicillin-Resistant
Staphylococcus aureusInfections in the United States. JAMA.
2007;298:1763-1771.
- The Centers for Disease Control and Prevention.
http://www.cdc.gov/mrsa/ . Accessed October, 17, 2007.
- The Centers for Disease Control and Prevention.
http://www.cdc.gov/mrsa/ . Accessed October 3, 2007.
- Robiscek A, Beaumont JL, Paule SM, et al. 2008. Universal
Surveillance for Methicillin-Resistant Staphylococcus aureus Annals
Intern Med. 148:409-419.
- Bootsma MC, Diekmann O, Bonten MJ. Controlling methicillin-resistant
Staphylococcus aureus: Quantifying the effects of interventions and
rapid diagnostic testing. PNAS. 103:5
MLO’s
Continuing Education Test is available online only.
Print out and mail a copy with your check, or use the new online CE test
and convenient online payment feature available through the auspices of
Northern Illinois University.
Go to www.mlo-online.com and
look under CE Tests.