WOBURN, Mass., Oct. 11 /PRNewswire/ -- In conjunction with the recently concluded 46th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in San Francisco, Dr. Graeme Forrest, M.D., Infectious Diseases Physician and Director of Antimicrobial Utilization at the University of Maryland Medical Center (UMMC), presented data on the impact that rapid testing with PNA FISH(TM) has on patient care. Since 2003, UMMC has incorporated PNA FISH results into treatment algorithms for managing patients with bloodstream infections.
PNA FISH is a genetics-based molecular diagnostic assay that provides species identification for bacteria and yeast directly from positive blood cultures. While conventional microbiology methods can take 1 to 3 days longer, PNA FISH results are reported a few hours after a blood culture turns positive and can have an early therapeutic impact.
In summary, Dr. Forrest concluded that effectively implementing PNA FISH, via coordinated efforts between the clinical laboratory, pharmacy and medical staff, can result in:
* Improved patient safety -- Early appropriate and effective antibiotic therapy -- Potential to decrease mortality in some situations * Decreased antimicrobial utilization * Decreased hospital length of stay (LOS) * Significant cost savings (often unrecognized) * Development of new therapeutic guidelines
Thais T. Johansen, President and CEO of AdvanDx said, “The data from the University of Maryland Medical Center studies show that rapid and accurate diagnostic results from PNA FISH can have a significant impact on improving patient care and overall hospital operations. That is a plus for both patients and hospitals and we are very encouraged to see the same trend occurring at hospitals throughout the United States.”
Reduction in Vancomycin Use and Length of Stay Leading to Improved Bed and Resource Utilization for CNS Contaminated Blood Cultures
Positive blood cultures don’t always constitute true infections. In fact, even though only about 10% of all blood cultures performed annually in the United States turn positive, indicating a bloodstream infection, 30% or more of those turn positive due to contamination with common skin bacteria known as Coagulase-Negative Staphylococci (CNS). However, given that these bacteria are closely related to S. aureus which almost always causes true and serious infections, patients with CNS contaminated blood cultures are often unnecessarily treated with broad-spectrum antibiotics, especially vancomycin, leading to prolonged hospital stays.
As part of their antimicrobial management program, a team lead by Dr. Forrest at UMMC implemented a treatment algorithm employing rapid S. aureus PNA FISH results to identify S. aureus bloodstream infections as early as possible or rule-out S. aureus from positive blood cultures. The rapid results are used to ensure aggressive therapy for patients with S. aureus infections, as well as identify those patients where blood cultures turned positive due to contamination, and avoid unnecessary therapy. According to the data presented by Dr. Forrest, the program has had the greatest impact on non-ICU patients with contaminated blood cultures for which the medical center has seen:
* Significant reduction in unnecessary vancomycin use * Reduction in median hospital length of stay of 2 days (from 6 to 4 days) * Increased bed utilization * Cost savings per patient of $4,005. The cost savings included $2,704 in reduced bed costs, $985 in reduced pharmacy costs and $316 in reduced laboratory costs.
The data were published in the July 2006 Issue of the Journal of Antimicrobial Agents and Chemotherapy.(1)
Optimizing Antifungal Therapy for Candidemia
In 2004, UMMC implemented C. albicans PNA FISH(TM) in order to report C. albicans and non-C. albicans results from Yeast-positive blood cultures. A treatment algorithm, based on PNA FISH, was developed and implemented to ensure appropriate antifungal therapy for patients with Candidemia and reduce unnecessary use of broad-spectrum and expensive agents, such as caspofungin. Following a full year of implementation, a retrospective study was performed comparing candidemia treatment data from 2003, before C. albicans PNA FISH was implemented, to 2004, after the test was implemented.
According to the data from the study presented by Dr. Forrest, implementation of the treatment algorithm based on C. albicans PNA FISH results led to a reduction in antifungal drug costs of $1,800 per candidemia patient, without affecting mortality. The greatest reduction in drug costs came from a reduction in caspofungin use for patients with C. albicans. During the study, UMMC discovered a sharp increase in the number of candidemias due to Candida dubliniensis, from 0/76 (0%) cases in 2003 to 6/72 (8%) in 2004. Further analysis revealed that conventional methods, such as germ-tube testing used in 2003, misidentified C. dubliniensis as C. albicans, whereas after the implementation of PNA FISH in 2004, C. dubliniensis was no longer misidentified as C. albicans.
The data were published in the September 2006 issue of the Journal of Clinical Microbiology. Data from a follow-up study, presented during the 46th ICAAC Annual Meeting, showed that when the treatment algorithm for candidemia was not followed, 17% of patients received ineffective therapy for their candidemia.(2)
Guiding Effective Antibiotic Therapy for Enterococcal Bloodstream Infections
Bloodstream infections due to vancomycin-resistant enterococci (VRE) are frequently treated inadequately with antibiotics. Data first presented in May 2006 at the 106th ASM General Meeting in Orlando, Florida, showed that while E. faecalis blood culture isolates were 100% susceptible to ampicillin and 95% susceptible to vancomycin at UMMC, other enterococci isolates, including E. faecium, were often resistant to both ampicillin and vancomycin, i.e., VRE. Of 14 patients with other enterococci in the study, 9/14 (64%) received ineffective initial therapy, with a median change to effective therapy of 3 days. For the patients receiving ineffective initial therapy, 6/7 (85%) eventually died.(3)
Subsequent to the study on Enterococcus species blood culture isolates, UMMC initiated a study on using a treatment algorithm for Enterococcal bloodstream infection that employs E. faecalis PNA FISH(TM) to speed up identification of E. faecalis, other enterococci and rule-out enterococci from blood cultures containing Gram-positive cocci in chains or pairs (GPCPC). According to the treatment algorithm developed by Dr. Forrest, the following treatments are administered, depending on the results of E. faecalis PNA FISH:
* Ampicillin for E. faecalis (Positive - Green Fluorescing Cells) * Linezolid for other enterococci (Positive - Red Fluorescing Cells) * Ampicillin/Ceftriaxone for non-enterococci (Negative - No Fluorescing Cells)
Results of the study on the new treatment algorithm for Enterococcal bloodstream infections will be presented at the upcoming Infectious Diseases Society of America (IDSA) 2006 Annual Meeting in Toronto, Canada (Oral abstract presentation 131).(4)
About Bloodstream Infections
Bloodstream infections, also known as bacteremia, cause significant morbidity and mortality and are among the most common healthcare-associated infections. Every year, 350,000 patients acquire bloodstream infections while in hospitals in the US, resulting in more than 90,000 deaths (25%) and significant costs to the healthcare system. At the first sign of infection, such as a positive blood culture with Gram-positive cocci in clusters (GPCC), physicians often treat empirically with broad-spectrum antibiotics to cover the risk of resistant pathogens, especially methicillin-resistant S. aureus (MRSA). Rapid results from the microbiology lab are therefore critical to support appropriate antibiotic therapy.
About PNA FISH(TM)
PNA FISH(TM) is a qualitative nucleic acid hybridization assay intended for identification of bacteria and yeast species from blood cultures. The 2.5 hours fluorescence in situ hybridization (FISH) assay uses fluorescence- labeled peptide nucleic acid (PNA) probes that target the species-specific ribosomal RNA (rRNA) in bacteria and yeast. Results are visualized using fluorescence microscopy. Fluorescing cells indicates the target species, while no fluorescence indicates another species is present in the positive blood culture.
About AdvanDx
AdvanDx, Inc. develops and markets in vitro diagnostic kits, based on its PNA FISH(TM) and EVIGENE(TM) technologies to aid in the diagnosis and prevention of infectious diseases. The PNA FISH and EVIGENE product lines provide rapid identification results for bacteria and yeast supporting appropriate antibiotic therapy and overall patient care. PNA FISH is available for in vitro diagnostic use (IVD) in both the United States and Europe, while EVIGENE is available for research use only (RUO) in the United States and for in vitro diagnostic use in Europe. Headquartered on the 128 technology highway around Boston, AdvanDx has established R&D facilities both in the United States and Denmark, with sales and marketing capabilities located throughout the United States and Europe. For more information, please visit http://www.AdvanDx.com or call +1-781-376-0009.
(1) Forrest et al. Impact of rapid in situ hybridization testing on coagulase-negative staphylococci positive blood cultures. J Antimicrob Chemother. 2006 Jul;58(1):154-8 (2) Forrest et al. Peptide nucleic acid fluorescence in situ hybridization-based identification of Candida albicans and its impact on mortality and antifungal therapy costs. J. Clin. Microbiol. 2006 44: 3381-3383. (3) Johnson et al. Rapid Identification of Enterococcus Species in Positive Blood Cultures with Therapeutic Implications. 2006. Poster # C-147. 106th ASM, Orlando, Florida (4) Toombs et al. Impact of Peptide Nucleic Acid (PNA) Fluorescence in situ Hybridization (FISH) for Enterococcal blood stream infections. Oral Abstract #131, IDSA 2006 Annual Meeting, Toronto, Canada
AdvanDx, Inc.
CONTACT: Philip Onigman of AdvanDx, +1-781-376-0009,philip.onigman@advandx.com
Web site: http://www.AdvanDx.com/
