update on molecular diagnostics

Update on Molecular Diagnostics

How does new molecular technology change the field of clinical microbiology ?

Stefan Riedel, MD, PhD, D(ABMM) FASCP, FCAP

Assistant Professor, Pathology

The Johns Hopkins University, School of Medicine

Director, Clinical Pathology Laboratories Johns Hopkins Bayview Medical Center

Conflict of Interest / Disclosures

Microbiology Scientific Advisory Board: • Iris Diagnostics, Chatsworth, CA

Speakers’ Bureau • BD Diagnostics, Franklin Lakes, NJ, ª • Iris Diagnostics, Chatsworth, CA, ª • Siemens Healthcare Diagnostics, Tarrytown, NY ª

Research support: • BRAHMs Diagnostics, Annapolis, MD* • Thermo-Fisher, Scientific, Middletown, VA • BD Diagnostics, Franklin Lakes, NJ • Iris Diagnostics, Chatsworth, CA • Cubist Pharmaceuticals, Lexington, MA • Meridian Bioscience, Cincinnati, OH • AdvanDx, Woburn, MA • Siemens Healthcare Diagnostics, Tarrytown, NY

*Funding and materials used in the study described in this presentation were provided by BRAHMS Diagnostics, Annapolis, MD. Dr. Riedel has continued financial and material support for procalcitonin research, provided by Thermo Fisher and BRAHMS. The terms of this agreement are being managed by the Johns Hopkins University in accordance with its conflict of interest policies.

ªDr. Riedel’s participation in various speakers’ bureaus is managed by the Johns Hopkins University in accordance with its conflict of interest policies. All opinions expressed and/or implied in this presentation are solely those of Dr. Riedel. The content of this presentation does not represent or reflect the views of the Johns Hopkins University or the Johns Hopkins Health System.

Objectives – Describe the available molecular diagnostic tests that hold

promise for use in clinical microbiology

– Understand the limitations of molecular diagnostic methods, and how those limitations impact diagnosis, treatment, and surveillance in clinical settings

– Understand the path of implementation and quality assurance issues related to molecular diagnostics

– Understand and discuss potential for new technologies and applications in the rapidly changing diagnostic environment of clinical microbiology

Conventional vs. Molecular Diagnostic Methods

Even 10 years ago … conventional culture-based methods were routine methods for pathogen detection

• require viable organisms • require lengthy time of incubation

• result in longer TAT (> 24 h) for results

Christian Gram (1853 – 1938)

Robert Koch (1843 – 1910)

Friedrich Loeffler (1852 – 1915)

Standard Microbiology References

• Bergey’s Manual of Systematic Bacteriology • ASM – Manual of Clinical Microbiology

Clinical Microbiology Laboratories

• match results for their unknown clinical isolates to references • not infrequently: IMPERFECTED MATCHES FOR IDs

1980s – a new standard is approaching….

phylogenetic relationships of bacteria (and all life forms) by analysis of 5S, 16S, 23S rRNA

Woese CR 1987; Microbiol Rev 51: 221-271 Woese CR, Stackebrandt E, Macke TJ, Fox GE 1985; Syst Appl Microbiol 6: 143-151

Universal phylogenetic tree based on the 16S rRNA gene sequence comparisons.

Clarridge J E. Clin. Microbiol. Rev. 2004;17:840-862 Pace N R. Science 1997;276:734-740

The Clinical Continuum

Intervention !

Exposure

Incubation Period

Disease manifestations

Seek provider care

Clinical evaluation

Care plan

Implementation Specimen ordering

Specimen collection

Specimen transport

Specimen processing

Organism identification

Performance of AST

AST results reporting

Clinician processing information

To treat or not to treat….

Today’s Concerns for Antimicrobial Utilization

Who truly benefits from antibiotic therapy ?

What is the optimal duration of therapy ?

What factors drive inappropriate prescribing of antibiotics ?

• diagnostic uncertainty • lack of knowledge

• unavailability of microbiology test results / services • unavailability of infectious disease specialty consultation

• pharmaceutical marketing pressure • fear of missing a life-threatening infection

Length of Time to Detection Analysis

Earlier is better !

• 17% decrease in mortality when Gram stains from positive blood cultures are reported within < 1 hours Bauer K, et al. Clin Infect Dis 2010; 51: 1074

• More rapid detection of bacteremia will improve antimicrobial treatment/ switching and therefore clinical outcome of sepsis Kerremans J, et al. J Clin Microbiol 2009; 47 (11): 3520

• Timely reporting of AST results greatly improved patient outcomes Barenfanger J et al. J Clin Microbiol 1999; 37: 1415 Doern GV, et al. J Clin Microbiol 1994; 32: 1757

Laboratory interventions that decrease TAT can be effective

The Evolution of Molecular Diagnostic Methods

“If you build it they will come…”

Technological developments and

improvements

Commercial profit

The Evolution of Technology in Clinical Microbiology

1953 1983 1995 2005 2012

PCR developed

DNA microarray developed

High-throughput sequencing developed

Cost of sequencing $ 5,000 per Megabase

Cost of sequencing $ 15 per Megabase

Cost of sequencing $ 0.50 per Megabase

DNA discovered

MassTagPCR developed

2001

2008

Adapted from: Lipkin W . Nature Reviews, Microbiology 2013; 11: 133 - 141

Can and will molecular tests replace traditional microbiology methods?

Can molecular tests replace traditional methods?

Can current laboratory professionals be effectively trained to routinely perform these highly complex assays ?

Will physicians understand & accept the results and change their practice ?

The questions & concepts to consider

Are the decreased TAT and improved sensitivity worth the additional cost ?

What pre-analytical and analytical changes need to be implemented ?

Baron EJ 2011; J Clin Microbiol 49: S43

And there are more questions….

How does the emerging molecular technology affect smaller clinical microbiology laboratories ?

Is ribosomal RNA gene sequencing the new or current “gold standard” in microbial identification?

• 10% to 20% of clinical isolates are novel organisms and escape phenotypic identification methods • molecular methods have greatly advanced in recent years • molecular methods have (very) short TAT to results reporting • 16S rRNA analysis is new basis for taxonomy

Zhang W, Versalovic J 2007. J Molecular Diagn 9: 572

Specific Pathogen Identification, when conventional methods fail to achieve high level confidence for organism identification,

incl. pathogen discovery

Specific Pathogen Identification, for organisms associated with nosocomial transmission (infection control):

e.g. MRSA , C. difficile

Applications for Molecular Diagnostics

Specific Pathogen Identification, for organisms associated with disease outbreak or emerging pathogens:

e.g. H1N1 influenza , E. coli O104:H4

Specific Pathogen Identification for disease surveillance and other epidemiologic purposes (e.g. microbiome project)

Molecular Microbiology*

Respiratory Virus Testing (Influenza, RSV, hMPnV, etc.)

Clostridium difficile (diagnosis; tcdA, tcdB)

Mycobacterium tuberculosis

Neisseria gonorrhea ; Chlamydia trachomatis

VRE Surveillance (vanA, vanB)

Norovirus

Enteric Pathogen Testing

Enterovirus and HSV

MRSA Surveillance

Group B Streptococcus Bordetella pertussis

*List of organisms is not all inclusive

Molecular Microbiology*

Cepheid: GeneXpert (modular real-time PCR)

Nanosphere (Verigene Clinical Microbiology)

AdvanDx: PNA-FISH (non-amplified DNA probes)

BD: BD Max™ (automated specimen processing,

real-time PCR)

MALDI-TOF MS (Bruker)

Film Array Technology ( Idaho Technology, Inc. / BioFire)

SeptiFast multiplex PCR (Roche)

*List of technologies is not all inclusive

Clinical Application for Molecular Diagnostics in Microbiology

Direct Pathogen Detection from a Clinical Specimen

Broad Based Assays

Novel Organism/Pathogen Discovery

Bacteremia / Sepsis

• approx. 750,000 episodes annually in U.S. – ~250,000 nosocomial episodes of BSI

• Mortality rate: 14% (community-onset BSI) - 34% (nosocomial BSI)

– risk of death from septic shock increases by 7% with every hour until start of appropriate/targeted therapy

– 10th leading cause of death – Substantial reduction of quality of life in survivors

• Attributable cost: ~ $ 9.6 billion

A common problem with significant clinical and

cost ramifications !

Danai et al. Chest 2006; 129: 1432-1440 Martin et al. NEJM 2003; 348: 1546-1554 Wisplinghoff et al. CID 2004; 39: 309-317

The Traditional Approach A two bottle system with blood specimen

split evenly between an

AEROBIC and an ANAEROBIC bottle.

Traditional Laboratory Methods rely on Cultivation of Pathogens!

• preliminary results within 1-3 days • definitive results often require more than 3-5 days

• ineffective for modification / de-escalation of antimicrobial therapy • contributes to increased mortality and emergence of MDR organisms

Rapid Identification of BSIs and other Infections – the current situation

Wolk et al. 2011. J Clin Microbiol 49 (9S): S62-S57 ; Tenover 2010. Ann NY Acad Sci 2013: 70-80

Clear benefits of rapid reporting of Gram Stain results and timely reporting of AST results

Doern et al. 1994. J Clin Microbiol 32: 1757-1762 Barenfanger et al. 1999. J Clin Microbiol 37: 1415-1418 Barenfanger et al. 2008. Am J Clin Pathol 130: 870-876

Peptide Nucleic Acid Fluorescent in situ Hybridization (PNA-FISH)

• Fluorescence tagged peptide nucleic acid probe (AdvanDx) - detects S. aureus-specific 16SrRNA

• Differentiates S. aureus from staphylococci other than S. aureus,

directly from blood cultures

• Sensitivity 99-100%; Specificity 96-100% Chapin K, et. al. 2003. J Clin Microbiol 41:4324

Gonzalez V, et. al. 2004. Eur J Clin Microbiol Infect Dis 23:396

Oliveira K, et. al. 2002. J Clin Microbiol. 40:247

Forrest et. al. 2006. J Antimicrob. Chemother. 58:154-58

Other PNA FISH Assays • C. albicans and C. glabrata

• Yeast Traffic light PNA FISH: Candida albicans and/or Candida parapsilosis,

Candida tropicalis and Candida glabrata and/or Candida krusei

• Enterococcus faecalis vs. Enterococcus not faecalis (faecium)

• GNR: P. aeruginosa vs. E. coli • GNR: E. coli +/- K. pneumoniae

versus P. aeruginosa (traffic-light probe)

PNA-FISH & Coagulase-negative Staphylococci Forrest et al. 2006. J Antimicrob Chemother 58: 154-158

Implementation of PNA-FISH for CoNS in BCs in conjunction with AMT

• lower hospital costs ( approx. $ 4,000 less per patient) • decreased length of stay (approx. 2 days per episode)

• decreased use of vancomycin

Ly et al. 2008. Clin Risk Manag 4: 637-640 similar results for LOS and cost

Forrest et al. 2008. Antimicrob Agents Chemother 52: 3558-3563 earlier initiation of appropriate antimicrobial therapy for HA E. faecium bacteremia

Holtzman et al. 2011. J Clin Microbiol 49 (4): 1581-1582

Impact of PNA-FISH for CoNS in BCs in the absence of AMT

• accurate performance of PNA FISH test, with high sensitivity & specificity • no active reporting by laboratory & no AMT support/guidance

• NO reduction in LOS (p = 0.35) and vancomycin use (p = 0.49) between control and study group patients !

Newer, improved PNA FISH Assays: QuickFISH* (*not all assays are currently FDA approved in the U.S.)

• probe quenching complexes eliminate need to wash away excess probe

• upon heating, quencher & probe will separate, allowing fluorescent probe to hybridize with target rRNA

• upon cooling, unused probe will again combine with quencher

• 5 min “hands-on” time ; 20 min TAT for results

Gram Stain CAV call

Gram Stain + QuickFISH CAV call

Definitive ID + AST (LIS report)

Definitive ID + AST (LIS report)

PNA FISH + 2nd CAV call

12-24 h

12-24 h

8-72 h

10-72 h

1.5-2 h

Will physicians act upon 2nd CAV call ?

Additional studies will hopefully show difference in clinical utility.

Molecular Amplified Technologies

MRSA vs. MSSA

• GeneOhm™ StaphSR : BD GeneOhm™ • Xpert MRSA/SA : Cepheid Diagnostics

Broad-based Assays* Assays performed directly on blood

• SepsiTest : Molzym, Bremen, Germany • LightCycler SeptiFast : Roche, Mannheim, Germany

*not available in the U.S.

BD-GeneOhm StaphSR • Multiplex real time PCR assay run on the SmartCycler®

• Amplifies specific target sequence of S. aureus and a specific target near the SCCmec insertion site (orfX junction in MRSA)

• Contains internal control to detect inhibition • Results are reported as negative or positive for S. aureus and/or MRSA

Stamper, PS et al 2007. J Clin Microbiol 45: 2191-2196 • 300 positive blood cultures from 295 patients containing gpc

• 89 grew S. aureus (29.7%); 211 grew species other than S. aureus (mostly CoNS) • Overall results: 96.7% agreement between culture and PCR assay • MRSA detection

• Sensitivity 100%, Specificity 98.4%, PPV 92.6%, NPV 100%

• MSSA detection • Sensitivity 98.9%, Specificity 96.7%, PPV 93.6%, NPV 99.5%

Other studies noted some limitations….. • failure to detect certain SCCmec types

• misidentification of revertant strains (deleted or nonfunctional mecA genes)

• sensitivity 95.5%, specificity 95.6% in seeded study Snyder JW, et al. J Clin Microbiol 2009; 47: 3747-3748

Groebner SM, et al. J Clin Microbiol 2009; 47: 1689--1694

Additional Considerations

• TAT 2.5 h and expense to laboratory • likely to perform batch testing

Munson E, et al. J Clin Microbiol 2010; 47: 3747-3748

Riedel S, Carroll KC. J Infect Chemother 2010; 16: 301-316

Freezing of reagent master mix (up to 6 months) will decrease reagent waste and cost without compromising accuracy of test results

Cepheid Xpert MRSA/SA assay Rapid Detection of Staphylococcus aureus and MRSA in

Wound Specimens and Blood Cultures Wolk DM, et al. J Clin Microbiol 2009; 47: 823-826

Source and organism

% (no. of positive samples/total no.) Sensitivity Specificity PPV NPV

SSTI MRSA

97.1 (34/35)

96.2 (76/79)

91.9 (34/37)

98.7 (76/77)

S. aureus

100 (55/55)

96.6 (57/59)

96.5 (55/57)

100 (57/57)

BC MRSA

98.3 (57/58)

99.4 (346/348)

96.6 (57/59)

99.7 (346/347)

S. aureus

100 (120/120)

98.6 (282/286)

96.7 (120/124)

100 (282/282)

Cepheid Xpert MRSA/SA assay Rapid Detection of Staphylococcus aureus and MRSA in

Wound Specimens and Blood Cultures Wolk DM, et al. J Clin Microbiol 2009; 47: 823-826

Primers and probes detect sequences in:

• staphylococcal protein A (spa) gene, • the SCCmec inserted into the S. aureus chromosomal attB insertion site

• mecA gene

Sensitivity & specificity 100% and 98.6% for BC/SA isolates

Sensitivity & specificity 98.3% and 99.4% for BC/MRSA isolates

No issues with revertant strains

False positives due to MR-CoNS and isolates with SCCmec empty cassette

Broad-based Assays

• SepsiTest (Molzym) – performed directly on whole blood – targets conserved regions of 16S rRNA – broad range PCR combined with sequencing – detects > 300 different pathogens – TAT 8-12 h

• LightCycler SeptiFast (Roche) – performed directly on whole blood – multiplex real-time PCR – detects 25 different pathogens – TAT 3-30 h

Mancini N, et al. Clin Microbiol Rev 2010; 23: 235-251

Performance of the LCSeptiFast and the SepsiTest Leitner E, et al. J Microbiol Methods 2013; 92: 253-255

• samples were tested in parallel with BC, LCSF, and ST

• organisms considered true positive when growth in at least one BC bottle • potential skin contaminants considered true positives when present in two BC bottles • 33.3% (25/75) specimens were positive for 1 or more pathogens by any method used • 8 samples positive by LCSF but not by BC • 10 samples positive by ST but not by BC • “special gold standard”: BC plus reports of BC positivity within 7 days prior to specimen collection

Performance of the LCSeptiFast and the SepsiTest Leitner E, et al. J Microbiol Methods 2013; 92: 253-255

Assay Result

No. of specimens Comparison to BC

Positive Negative Sensitivity (%) [95% CI]

Specificity (%) [95% CI]

LCSF Positive 3 8 42.9 [15.8, 75.0] 88.2 [78.5, 93.9]

Negative 4 60

ST Positive 2 10 28.6 [8.2, 64.1] 85.3 [75.0, 91.8]

Negative 5 58

Comparison to designed gold standard LCSF Positive 7 4

63.7 [35.4, 84.8] 93.8 [85.0, 97.5] Negative 4 60

ST Positive 3 9 37.5 [13.7, 69.4] 86.6 [76.4, 92.8]

Negative 5 58

LCSF, LightCycler® SeptiFast; ST, SepsiTest™; BC, blood culture; CI, confidence interval

Comparison of LCSF and ST against BC/”gold standard”

Broad-based Assays and Direct Pathogen Detection Compared to BC, some assays have sufficient

diagnostic sensitivity & specificity. Combination of LCSF with procalcitonin may increase sensitivity.

Assays have improved TAT: LCSF 6 h ; ST 4-5 h

Positive ST results have TAT of 8-9 h due to sequencing

Automated DNA extraction is essential when implementing Assays in routine clinical laboratories.

Wolk DM, et al. J Clin Microbiol 2011; 49: S62-S67 Mauro MV, et al. Diagn Microbiol Infect Dis 2012; 73: 308-311 Leitner E, et al. J Microbiol Methods 2013; 92: 253-255

Molecular Technology for HAI screening

MRSA

Clostridium difficile

• culture remains common method for MRSA screening in most European countries

• recent Clinmicronet survey (70 laboratories) found that 54% adopted molecular methods for MRSA detection

• chromogenic agar media have shown increased sensitivities of 93% t0 99% compared to standard media

Marlowe EM, Bankowski MJ. J Clin Microbiol 2011; 49: S53-S56

Methods for MRSA screening

Method Sensitivity Specificity TAT Cost Technologist skill level

Culture Low* 100 % 18-48 h low moderate

Molecular high <100% < 24 h high moderate to high

*improved sensitivity when using chromogenic agar media

Marlowe EM, Bankowski MJ. J Clin Microbiol 2011; 49: S53-S56

Chromogenic agar media • MRSASelect Bio-Rad nares, wounds • Spectra MRSA Remel nares, positive BC • ChromID MRSA bioMérieux nares • BBL CHROMagar MRSA Becton Dickinson nares

Points to consider for method selection for MRSA Screening

Impact of MRSA on hospitals remains high!

laboratory – infection control – pharmacy – AMT

Screening of high-risk patients upon admission

Culture method has longer TAT but amenable to optimization of sensitivity

Culture method has longer TAT but amenable to optimization of sensitivity

Standardization of MRSA screening for both methods

Surveillance of test performance (emerging new variant strains?)

Points to consider for method selection for MRSA Screening

Hospital / Institution will need to determine the best fit for their setting

Collaboration between

Laboratory – Infection Control – Pharmacy – AMT

More evidence based studies needed to determine

• cost effectiveness of chosen methods (molecular vs. cultue) • studies focused on patient outcomes • continued method accuracy evaluation


• Formidable nosocomial pathogen

• responsible for up to 25% of antibiotic associated diarrhea • severe CDI results in extensive morbidity and mortality (6%)

• recently increased CDI frequency both in hospital and community settings

• emergence of hypervirulent strains (ribotype 027; NAP1)

High sensitivity & specificity

Rapid TAT, in order to timely implement therapy & isolation

General Principles

• Enterotoxin (Toxin A) – TcdA : cdtA

• Cytotoxin (Toxin B) – TcdB : cdtB

• additional toxins: cdtC, cdtD, cdtE

• Clostridium difficile – first described 1978

• Significant increase in incidence over the past decade

• NAP-1 (North American pulsed-field gel electrophoresis type 1 strain) – increase of more severe cases ?

TcdA+/TcdB+ : all cytotoxic; majority of strains causing disease in animals and humans TcdA-/TcdB- : nontoxigenic strains; not cytotoxic or virulent; may be PCR positive due to having parts of the toxin gene TcdA-/TcdB+ : produce only cytotoxin; may not be detected by commercial EIA method (10% of clinical cases; >40% in pediatric patients)

C. difficile – Laboratory Diagnosis

Test Target detected

TAT Sensitivity (%)

Specificity (%)

Cytotoxin Toxin B 1-3 days 90-95 95

Toxin Culture Toxigenic C. difficile

3-5 days 80-90 >95

EIA Toxin A or A/B

Toxin A or Toxin A&B

hours 97-98 75-80

EIA GDH C. difficile

hours 70-80 95-100

EIA GDH and Toxin A/B

C. difficile and Toxin A/B

hours 97-98 95-100

RT-PCR Toxigenic C. difficile

hours 80-99 >98

Bartlett J. ICHE 2010; 31: S35 Stamper P, et al. J. Clin. Microbiol. 2009; 47: 373

GDH: glutamine dehydrogenase

C. difficile: molecular tests

BD GeneOhm (Becton, Dickinson & Co.)

GeneXpert C. difficile (Cepheid)

Illumigene (Meridian Bioscience)

AmpliVue C. difficile (Quidel Diagnostics)

tcdB

PCR molecular beacon

TAT 2-3 h

tcdA

LAMP methodology

TAT 1 h

tcdA, tcdB, tcdC deletion 117

PCR, Taqman (one cartridge)

TAT 1 h

Conserved DNA region A+B+ and A-B+ strains

Hand-held device Isothermal helicase-dependent amplification

TAT 20 min

Result

Gold standard (no. samples) Sensitivity

(%) [CI 95%]

Specificity (%) [CI 95%]

Accuracy (%)

Positive Negative

XPert C. difficile

Positive Negative

44 1

1 48

97.8 [93.5–102.1]

97.9 [93.9–101.9] 97.9

BD GeneOhm Cdiff

Positive Negative

43 2

1 48

95.5 [89.4–101.5]

97.9 [93.9–101.9] 96.8

illumigene C. difficile

Positive Negative

39 6 49 86.7

[76.8–96.6] 100 93.6

CI, Confidence Interval

Performance Characteristics Molecular C. difficile Tests

Viala C, et al. J Microbiol Methods 2012; 90: 83-85

Performance Characteristics Molecular C. difficile Tests

BD GeneOhm , Cepheid Xpert, Illumigene

• relatively rapid and easy-to-perform tests

• similar performance regarding sensitivity/specificity

• Xpert and Illumigene are not time-consuming

• Xpert will detect ribotype 027

Additional studies will need to evaluate the role of the Quidel AmpliVue test

Promising new technologies

PCR/ESI-MS PCR combined with electrospray ionization mass spectrosmetry

MALDI-TOF MS Matrix assisted laser desoprtion ionization-time of flight mass spectrometry

DNA-Pyrosequencing-based Pathogen detection

FilmArray real-time PCR assays

MALDI-TOF MS • Identification of protein profiles derived from highly

conserved proteins

• Currently requires subculture before identification

• Low consumable cost

• Rapid organism identification

• Evidence of accurate bacterial organism ID – contaminant bacterial organisms – Whole colony needed for analysis – feasibility in clinical laboratory? – Cost for instrumentation?

Wolk DM et al. J Clin Microbiol 2011; 49: S62-S67 Maier T, et al. Chem Today 2007; 25: 68-71 Moussaoui W, et al. Clin Microbiol Infect 2010; 16: 1631-1638

FilmArray Technology (Idaho technology, Inc.)

Highly multiplexed automated PCR assay

• integrates specimen processing, nucleic acid amplification, and detection into a pouch

• premarket version detects 17 respiratory viruses plus three bacteria

• mechanical cell lysis using zirconium beads; nucleic acid capture and purification using metallic beads

• nested PCR; first stage is highly multiplexed PCR, second stage individual PCR mixtures (real-time PCR)

Adenovirus, bocavirus, hMPnV, influenza, parainfluenza 1-4, rhinovirus, RSV, Enterovirus, coronavirus, B. pertussis, Ch. Pneumoniae, M. pneumoniae)

FilmArray has excellent performance characteristics and allows for detection of a large number of pathogens.

Loeffelholz MJ, et al. J Clin Microbiol 2011; 49: 4083-4088

Specific Pathogen Identification, when conventional methods fail to achieve high level confidence for organism identification,

incl. pathogen discovery

Specific Pathogen Identification, for organisms associated with nosocomial transmission (infection control):

e.g. MRSA , C. difficile

Applications for Molecular Diagnostics

Specific Pathogen Identification, for organisms associated with disease outbreak or emerging pathogens:

e.g. H1N1 influenza , E. coli O104:H4

Specific Pathogen Identification for disease surveillance and other epidemiologic purposes (e.g. microbiome project)

“Advanced diagnostic technology will continually rely on the basic principles and practice of culture and identification.”

Dunne W.M., Pinckard J.K., Hooper L.V. Clinical Microbiology in the year 2025. J. Clin. Microbiol. 2002; 40 (11): 3889-3893

TRUE FALSE

If the new, molecular technology can be adapted to all hospitals, and

Assuming that accuracy and performance characteristics remain high ….

Molecular- and protein-based testing methods will replace traditional biochemical test methods, but will interface with current/traditional

antimicrobial susceptibility testing.

However: Culture methods are NOT obsolete !

Future Trends in Laboratory Diagnostics

Continued development of new technologies, and greater awareness & use of molecular test methods.

• need for expert groups to combine and assess data from multicenter studies

to meet regulatory requirements (e.g. CLIA, CAP, FDA)

• establish expert groups to develop new technologies and diagnostic algorithms through multicenter, randomized, clinical studies

• integrate existing and novel technologies for diagnostic algorithms through

collaborative networks between clinicians and the laboratory

Conclusions • Considering cost, complexity, and throughput newly developed

technologies may only be available to university-based diagnostic laboratories

• Need for further development of rapid diagnostic methods, including simple molecular diagnostics; however, culture based methods will NOT obsolete in the near future

• Need to develop middleware products that allow for interfacing of HIS/LIS users from multiple healthcare institutions with new technologies such as mass spectrometry

• Infectious Disease Physicians, Infection Control Practitioners, and Hospital Epidemiologists will need to assist Microbiologists / Laboratory Directors in clinical validation of new technologies

update on molecular diagnostics

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