CE CONTINUING EDUCATION
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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.
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.
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.
- 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.
Labs take new role in antibiotic stewardship, championing improved diagnoses, guiding therapy, saving lives, and cutting costs
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.
- 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.
Implementing a real-time PCR assay for rapid surveillance of MRSA
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
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
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.
- 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
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