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TITLE:TITLE:TITLE:TITLE: The Verigene Gram Positive Blood Culture TestThe Verigene Gram Positive Blood Culture TestThe Verigene Gram Positive Blood Culture TestThe Verigene Gram Positive Blood Culture Test in in in in Gram Gram Gram Gram

PositivePositivePositivePositive BacteremiaBacteremiaBacteremiaBacteremia

AUTHOR:AUTHOR:AUTHOR:AUTHOR: Jeffrey A. Tice, MDJeffrey A. Tice, MDJeffrey A. Tice, MDJeffrey A. Tice, MD

AssociateAssociateAssociateAssociate Professor of MedicineProfessor of MedicineProfessor of MedicineProfessor of Medicine

Division of General InternalDivision of General InternalDivision of General InternalDivision of General Internal MedicineMedicineMedicineMedicine

Department of MedicineDepartment of MedicineDepartment of MedicineDepartment of Medicine

University of California San FranciscoUniversity of California San FranciscoUniversity of California San FranciscoUniversity of California San Francisco

PUBLISHER:PUBLISHER:PUBLISHER:PUBLISHER: California Technology Assessment ForumCalifornia Technology Assessment ForumCalifornia Technology Assessment ForumCalifornia Technology Assessment Forum

DATE OF DATE OF DATE OF DATE OF

PUBLICATION:PUBLICATION:PUBLICATION:PUBLICATION: October 17October 17October 17October 17, 2012, 2012, 2012, 2012

PLACE OF PLACE OF PLACE OF PLACE OF

PUBLICATION:PUBLICATION:PUBLICATION:PUBLICATION: San Francisco, CASan Francisco, CASan Francisco, CASan Francisco, CA

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THE VERIGENE GRAM POSITIVE THE VERIGENE GRAM POSITIVE THE VERIGENE GRAM POSITIVE THE VERIGENE GRAM POSITIVE BLOOD CULTURE TESTBLOOD CULTURE TESTBLOOD CULTURE TESTBLOOD CULTURE TEST

IN GRAM POSITIVE BACTEREMIAIN GRAM POSITIVE BACTEREMIAIN GRAM POSITIVE BACTEREMIAIN GRAM POSITIVE BACTEREMIA

A Technology Assessment

INTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTION

The California Technology Assessment Forum (CTAF) was asked to assess the

evidence for the use of the Verigene Gram Positive Blood Culture Nucleic Acid Test for

patients with gram-positive bacteremia identified with blood culture. Current blood

culture technology takes 24 to 48 hours after the culture becomes positive to identify the

exact species of bacteria and its resistance patterns. The Verigene Gram Positive Blood

Culture Nucleic Acid Test, one of the first molecular diagnostic tests approved by the

FDA for identifying bacteria, may reduce that time to less than three hours.

BACKGROUNDBACKGROUNDBACKGROUNDBACKGROUND

Bacterial infections of the blood (bacteremia)

Experts estimate that there are approximately 200,000 episodes of bacteremia

each year in the United States.1,2 The observed mortality for patients hospitalized with

bacteremia ranges from approximately 15% to 35% of patients, although it has been

declining recently.3-5

Blood cultures are the gold standard for the diagnosis of bacteremia, although

guidelines are not clear about when they should be drawn. Certain conditions, such as

sepsis syndrome, endocarditis, and meningitis have a high probability of bacteremia,

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while others, such as cellulitis and community-acquired pneumonia have a low

probability of bacteremia.1 Blood cultures are commonly drawn in patients admitted to

the hospital with signs of infection, but only about 10% of the cultures are positive and

about half of the positive cultures are contaminants.3,5-7 Both false negative cultures

and false positive cultures increase the length of stay and expense of hospitalizations

for patients.8,9

Patients with bloodstream infections generally have only a small number bacteria

in their blood. Thus, multiple samples are drawn to increase the sensitivity for the

detection of the infection. Two blood cultures have a sensitivity of approximately 90%

and three cultures have a sensitivity of approximately 98%.10-12

Proper technique must be used to collect the blood in order to avoid

contamination with the bacteria that normally colonize our skin. The skin should be

cleaned with alcohol followed by tincture of iodine or chlorhexadine and the cultures

should never be drawn through an existing intravenous line.13-16 Even with proper

technique almost half of all positive blood cultures are false positives (contaminants).3

Approximately 10 to 30 mL of blood should be directly innoculated into bottles

containing the blood culture media. Modern laboratories now use continuous

monitoring blood culture systems in which computers monitor the culture media and

alert staff as soon as there is evidence of growth.17

New molecular diagnostic tests are being developed to more rapidly identify both

bacterial and fungal infections in the blood, improve the sensitivity for detection of the

pathogens, and to reduce the number of false positive blood cultures.18 Most of these

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are based on polymerase chain reaction based tests for the DNA of the most common

pathogens. These tests can also identify the genes responsible for antibiotic resistance

and thus guide the best choice of antibiotics. This should serve to improve the

outcomes of patients with bloodstream infections and reduce the overuse of broad

spectrum antibiotics when more selective agents are appropriate. The most widely

studied system, the LightCycler Septifast, is not yet approved for use in the United

States.19-27 The Vergiene Gram Positive Blood Culture Nucleic Acid Test has been

approved for use in the United States.

The Vergiene Gram Positive Blood Culture Nucleic Acid Test (BCBCBCBC----GP)GP)GP)GP)

The Verigene Gram-Positive Blood Culture Test is an automated test to identify the

genus, species and resistance patterns for a common set of gram-positive bacteria. The

BC-GP can be used as soon as a direct gram stain from a positive blood culture shows

gram-positive organisms. It takes a laboratory technician about five minutes to process

a specimen and then an automated machine completes the analysis in approximately

two and a half hours. The process breaks down bacterial DNA into small fragments and

then introduces oligonucleotides that are attached to gold nanoparticles. The

oligonucleotides are complementary to specific DNA segments of the target bacteria. A

second set of probes attached to specific locations on a glass microarray captures the

gold nanoparticles. An optical reader identifies which DNA segments are present based

on their location on the glass microarray.

The BC-GP test identifies thirteen of the most common gram-positive bacteria.

These include Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus

lugdunensis, Streptococcus pneumoniae, Streptococcus anginosus, Streptococcus

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agalactiae, Streptococcus pyogenes, Enterococcus faecalis, Enterococcus faecium,

Micrococcus species, Listeria species, the methicillin resistance marker mecA in

Staphylococcus aureus and epidermidis, and the two vancomycin resistance markers

vanA and vanB in Enterococcus faecalis and faecium.

Current blood culture technology requires approximately 24 to 48 hours to identify

the bacterial species and resistance patterns.28 The BC-GP test has the potential to

improve antibiotic selection and save lives.29,30

TECHNOLOGY ASSESSMENT (TA)TECHNOLOGY ASSESSMENT (TA)TECHNOLOGY ASSESSMENT (TA)TECHNOLOGY ASSESSMENT (TA)

TA Criterion 1:TA Criterion 1:TA Criterion 1:TA Criterion 1: The technology must have final approval from the appropriate The technology must have final approval from the appropriate The technology must have final approval from the appropriate The technology must have final approval from the appropriate

government regulatory bodies.government regulatory bodies.government regulatory bodies.government regulatory bodies.

The FDA approved the Vergiene Gram Positive Blood Culture Nucleic Acid Test on

June 28, 2012.

TA Criterion 1 TA Criterion 1 TA Criterion 1 TA Criterion 1 is met.is met.is met.is met.

TA Criterion 2:TA Criterion 2:TA Criterion 2:TA Criterion 2: The scientific evidence must permit conclusions concerning The scientific evidence must permit conclusions concerning The scientific evidence must permit conclusions concerning The scientific evidence must permit conclusions concerning

the effectiveness of the technology regarding health the effectiveness of the technology regarding health the effectiveness of the technology regarding health the effectiveness of the technology regarding health

outcomes.outcomes.outcomes.outcomes.

The Medline database, Embase, Cochrane clinical trials database, Cochrane reviews

database and the Database of Abstracts of Reviews of Effects (DARE) were searched

using the key words “Verigene” OR “Nanosphere” AND “gram positive” OR “blood

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culture.” The search was performed for the period from 1945 through September 2012.

The bibliographies of systematic reviews and key articles were manually searched for

additional references. The abstracts of citations were reviewed for relevance and all

potentially relevant articles were reviewed in full. We included all randomized trials in

women with invasive breast cancer that compared sentinel lymph node biopsy to

axillary lymph node dissection.

The literature search identified three potentially relevant studies and six abstracts

from the manufacturer. None of the references were articles published in peer-

reviewed journals.

Level of Evidence: NoneLevel of Evidence: NoneLevel of Evidence: NoneLevel of Evidence: None

TA Criterion 2 is TA Criterion 2 is TA Criterion 2 is TA Criterion 2 is not not not not met.met.met.met.

TA Criterion 3:TA Criterion 3:TA Criterion 3:TA Criterion 3: The technology must improve net health outcomes.The technology must improve net health outcomes.The technology must improve net health outcomes.The technology must improve net health outcomes.

Ideally studies should compare the outcomes of patients managed using the

results of the BC-GP test to those of patients managed with blood culture alone. Since

15% to 35% of patients with bacteremia die, hospital mortality would be the most

important outcome to assess. Additional outcomes of importance to patients would

include time to hospital discharge, complications of antibiotic therapy, and long-term

disability. Secondary outcomes supporting the utility of the BC-GP test would be

shorter time to definitive identification of the causative organism and shorter time to

appropriate antibiotic therapy. Less important, but supportive data, would include the

concordance of the GPBC test results with the final diagnosis using blood cultures

alone. There are no published papers in the peer-reviewed literature on the clinical

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outcomes of patients managed with the BC-GP or concordance of the test with blood

culture results

TA Criterion 3 is TA Criterion 3 is TA Criterion 3 is TA Criterion 3 is not not not not metmetmetmet

TA Criterion 4:TA Criterion 4:TA Criterion 4:TA Criterion 4: The technology must be as beneficial as any established alternatives.The technology must be as beneficial as any established alternatives.The technology must be as beneficial as any established alternatives.The technology must be as beneficial as any established alternatives.

The accepted alternative to BC-GP is routine blood culture techniques for

speciation and antibiotic sensitivity testing. There are no published studies comparing

BC-GP to routine blood cultures.

TA Criterion 4 is metTA Criterion 4 is metTA Criterion 4 is metTA Criterion 4 is met

TA Criterion 5:TA Criterion 5:TA Criterion 5:TA Criterion 5: The improvement must be attainable outside of the The improvement must be attainable outside of the The improvement must be attainable outside of the The improvement must be attainable outside of the

investigational setting.investigational setting.investigational setting.investigational setting.

No improvements have been demonstrated in the investigational setting.

TA Criterion 5 is met TA Criterion 5 is met TA Criterion 5 is met TA Criterion 5 is met

CONCLUSIONCONCLUSIONCONCLUSIONCONCLUSION

The BC-GP nucleic acid test is a promising approach to the diagnosis of

bloodstream infections. Gram positive infections represent at least 60% of all blood

cultures in the United States. In addition, the most important gram-positive pathogens

(Staphylococcus aureus and Enterococcus species) have important resistance patterns

that are identified by the BC-GP.

Theoretically BC-GP should reduce the time to the appropriate use of antibiotics

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for gram positive infections and this may reduce morbidity and mortality in these

patients. In addition, the reduction in the use of inappropriate antibiotics may reduce

complications from antibiotics in these patients and reduce the prevalence of resistant

organisms in health care settings and the community. However, at this time, there are

no studies documenting improvements in patient outcomes using BC-GP.

RECOMMENDATIONRECOMMENDATIONRECOMMENDATIONRECOMMENDATION

It is recommended that use of use of the Verigene Gram Positive Blood Culture

Nucleic Acid Test does not meet CTAF TA Criterion 2 through 5 for safety, effectiveness

and improvement in net health outcomes.

The CTAF Panel amended the above recommendation to state:

It is recommended that use of the Verigene Gram Positive Blood Culture

Nucleic Acid Test does not meet CTAF TA Criterion 2 through 5 for

safety, effectiveness and improvement in net health outcomes.

The CTAF Panel voted nine in favor of the amended recommendation and none

opposed.

October 17October 17October 17October 17, 2012, 2012, 2012, 2012

This is the first review of this technology by the California Technology Assessment

Forum.

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RECOMMENDATIONS OF OTHERSRECOMMENDATIONS OF OTHERSRECOMMENDATIONS OF OTHERSRECOMMENDATIONS OF OTHERS

Blue Cross Blue Shield Association (BCBSA)Blue Cross Blue Shield Association (BCBSA)Blue Cross Blue Shield Association (BCBSA)Blue Cross Blue Shield Association (BCBSA)

No assessments on this technology were found on the BCBSA TEC website.

Canadian Agency for Drugs and Technologies in Health (CADTH)Canadian Agency for Drugs and Technologies in Health (CADTH)Canadian Agency for Drugs and Technologies in Health (CADTH)Canadian Agency for Drugs and Technologies in Health (CADTH)

No reports on this technology were found on the CADTH website.

National Institute for Health and Clinical Excellence (NICE)National Institute for Health and Clinical Excellence (NICE)National Institute for Health and Clinical Excellence (NICE)National Institute for Health and Clinical Excellence (NICE)

No reports on this technology were found on the NICE website.

Centers for Medicare and Medicaid Services (CMS)Centers for Medicare and Medicaid Services (CMS)Centers for Medicare and Medicaid Services (CMS)Centers for Medicare and Medicaid Services (CMS)

There is no National Coverage Determination (NCD) code for this test.

Agency for Healthcare Research and QualityAgency for Healthcare Research and QualityAgency for Healthcare Research and QualityAgency for Healthcare Research and Quality (AHRQ)(AHRQ)(AHRQ)(AHRQ)

No reports on this technology were found at the AHRQ website.

Infectious Disease Society (ISD), Bay Area ChapterInfectious Disease Society (ISD), Bay Area ChapterInfectious Disease Society (ISD), Bay Area ChapterInfectious Disease Society (ISD), Bay Area Chapter

The ISD did not provide a position statement on this technology nor send a

representative to the meeting.

College of American Pathology (CACollege of American Pathology (CACollege of American Pathology (CACollege of American Pathology (CAPPPP))))

CAP did not provide a position statement on this technology and nor send a

representative to the meeting.

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ABBREVIATIONSABBREVIATIONSABBREVIATIONSABBREVIATIONS

CTAF California Technology Assessment Forum

DARE Database of Abstracts of Reviews of Effects

FDA US Food and Drug Administration

BC-GP Verigene Gram Positive Blood Culture Nucleic Acid Test

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REFERENCESREFERENCESREFERENCESREFERENCES

1.1.1.1. Coburn B, Morris AM, Tomlinson G, Detsky AS. Does this adult patient with

suspected bacteremia require blood cultures? JAMA. Aug 1 2012;308(5):502-511.

2.2.2.2. Munson EL, Diekema DJ, Beekmann SE, Chapin KC, Doern GV. Detection and

treatment of bloodstream infection: laboratory reporting and antimicrobial

management. Journal of clinical microbiology. Jan 2003;41(1):495-497.

3.3.3.3. Pien BC, Sundaram P, Raoof N, et al. The clinical and prognostic importance of

positive blood cultures in adults. Am J Med. Sep 2010;123(9):819-828.

4.4.4.4. Valles J, Calbo E, Anoro E, et al. Bloodstream infections in adults: importance of

healthcare-associated infections. J Infect. Jan 2008;56(1):27-34.

5.5.5.5. Weinstein MP, Towns ML, Quartey SM, et al. The clinical significance of positive

blood cultures in the 1990s: a prospective comprehensive evaluation of the

microbiology, epidemiology, and outcome of bacteremia and fungemia in

adults. Clin Infect Dis. Apr 1997;24(4):584-602.

6.6.6.6. Bates DW, Cook EF, Goldman L, Lee TH. Predicting bacteremia in hospitalized

patients. A prospectively validated model. Ann Intern Med. Oct 1 1990;113(7):495-

500.

7.7.7.7. Wilson ML. Clinically relevant, cost-effective clinical microbiology. Strategies to

decrease unnecessary testing. American journal of clinical pathology. Feb

1997;107(2):154-167.

8.8.8.8. Bates DW, Goldman L, Lee TH. Contaminant blood cultures and resource

utilization. The true consequences of false-positive results. JAMA : the journal of

the American Medical Association. Jan 16 1991;265(3):365-369.

9.9.9.9. Zwang O, Albert RK. Analysis of strategies to improve cost effectiveness of

blood cultures. J Hosp Med. Sep 2006;1(5):272-276.

10.10.10.10. Lee A, Mirrett S, Reller LB, Weinstein MP. Detection of bloodstream infections in

adults: how many blood cultures are needed? Journal of clinical microbiology.

Nov 2007;45(11):3546-3548.

12

11.11.11.11. Washington JA, 2nd. Blood cultures: principles and techniques. Mayo Clin Proc.

Feb 1975;50(2):91-98.

12.12.12.12. Weinstein MP, Reller LB, Murphy JR, Lichtenstein KA. The clinical significance of

positive blood cultures: a comprehensive analysis of 500 episodes of bacteremia

and fungemia in adults. I. Laboratory and epidemiologic observations. Rev Infect

Dis. Jan-Feb 1983;5(1):35-53.

13.13.13.13. Caldeira D, David C, Sampaio C. Skin antiseptics in venous puncture-site

disinfection for prevention of blood culture contamination: systematic review

with meta-analysis. J Hosp Infect. Mar 2011;77(3):223-232.

14.14.14.14. Little JR, Murray PR, Traynor PS, Spitznagel E. A randomized trial of povidone-

iodine compared with iodine tincture for venipuncture site disinfection: effects

on rates of blood culture contamination. Am J Med. Aug 1999;107(2):119-125.

11115.5.5.5. Schifman RB, Pindur A. The effect of skin disinfection materials on reducing

blood culture contamination. Am J Clin Pathol. May 1993;99(5):536-538.

16.16.16.16. Suwanpimolkul G, Pongkumpai M, Suankratay C. A randomized trial of 2%

chlorhexidine tincture compared with 10% aqueous povidone-iodine for

venipuncture site disinfection: Effects on blood culture contamination rates. J

Infect. May 2008;56(5):354-359.

17.17.17.17. Weinstein MP. Current blood culture methods and systems: clinical concepts,

technology, and interpretation of results. Clin Infect Dis. Jul 1996;23(1):40-46.

18.18.18.18. Murray PR, Masur H. Current approaches to the diagnosis of bacterial and

fungal bloodstream infections in the intensive care unit. Crit Care Med. Oct 3

2012.

19.19.19.19. Dubska L, Vyskocilova M, Minarikova D, Jelinek P, Tejkalova R, Valik D.

LightCycler SeptiFast technology in patients with solid malignancies: clinical

utility for rapid etiologic diagnosis of sepsis. Crit Care. 2012;16(1):404.

20.20.20.20. Lamoth F, Jaton K, Prod'hom G, et al. Multiplex blood PCR in combination with

blood cultures for improvement of microbiological documentation of infection

in febrile neutropenia. J Clin Microbiol. Oct 2010;48(10):3510-3516.

13

21.21.21.21. Lehmann LE, Hunfeld KP, Emrich T, et al. A multiplex real-time PCR assay for

rapid detection and differentiation of 25 bacterial and fungal pathogens from

whole blood samples. Med Microbiol Immunol. Sep 2008;197(3):313-324.

22.22.22.22. Lodes U, Meyer F, Konig B, Lippert H. [Microbiological sepsis screening in

surgical ICU patients with the "lightCycler" Septifast test--a pilot study]. Zentralbl

Chir. Jun 2009;134(3):249-253.

23.23.23.23. Mauro MV, Cavalcanti P, Perugini D, Noto A, Sperli D, Giraldi C. Diagnostic utility

of LightCycler SeptiFast and procalcitonin assays in the diagnosis of

bloodstream infection in immunocompromised patients. Diagn Microbiol Infect

Dis. Aug 2012;73(4):308-311.

24.24.24.24. Mussap M, Molinari MP, Senno E, et al. New diagnostic tools for neonatal sepsis:

the role of a real-time polymerase chain reaction for the early detection and

identification of bacterial and fungal species in blood samples. J Chemother. Oct

2007;19 Suppl 2:31-34.

25.25.25.25. Pasqualini L, Mencacci A, Leli C, et al. Diagnostic performance of a multiple real-

time PCR assay in patients with suspected sepsis hospitalized in an internal

medicine ward. J Clin Microbiol. Apr 2012;50(4):1285-1288.

26.26.26.26. Rath PM, Saner F, Paul A, et al. Multiplex PCR for rapid and improved diagnosis

of bloodstream infections in liver transplant recipients. J Clin Microbiol. Jun

2012;50(6):2069-2071.

27.27.27.27. Westh H, Lisby G, Breysse F, et al. Multiplex real-time PCR and blood culture for

identification of bloodstream pathogens in patients with suspected sepsis. Clin

Microbiol Infect. Jun 2009;15(6):544-551.

28.28.28.28. Tissari P, Zumla A, Tarkka E, et al. Accurate and rapid identification of bacterial

species from positive blood cultures with a DNA-based microarray platform: an

observational study. Lancet. Jan 16 2010;375(9710):224-230.

29.29.29.29. Kumar A, Roberts D, Wood KE, et al. Duration of hypotension before initiation of

effective antimicrobial therapy is the critical determinant of survival in human

septic shock. Crit Care Med. Jun 2006;34(6):1589-1596.

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30.30.30.30. Ly T, Gulia J, Pyrgos V, Waga M, Shoham S. 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. Jun

2008;4(3):637-640.