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Consensus Guidelines Recommend DNA Diagnostic Testing During Phase I of Chronic Wound Management

DNA diagnostics recommended in first 1-4 days

toenail infection

Consensus guidelines from a Global Wound Biofilm Expert Panel include the use of DNA diagnostics in the first 1-4 days of chronic wound therapy as part of early intervention. When all other healing measures are taken into account, there is strong evidence linking bacterial proliferation to chronic non-healing wounds. A sustained presence of proinflammatory agents degrades the extracellular matrix, inhibits cell migration, and prevents wound healing.

State-of-the-art qPCR + next-gen sequencing (NGS) increases precise species identification more than 20-fold when compared to culture. qPCR+NGS also provides an estimated percentage of the organisms present in the specimen. This specificity of organism identification and estimated quantification empowers the clinician to treat a patient with absolute confidence.

Published research shows accelerated healing with MicroGenDX

Standard of Care GroupGroup 1Group 2
Traditional Culture
with Systemic Antibiotics		Molecular Diagnostics with Systemic AntibioticsMolecular Diagnostics with Customized
Topical Antibiotics
48.5%
patients healed		62.4%
patients healed		90.4%
patients healed

A more comprehensive microbial view affords the greatest potential of diminishing polymicrobial communities within this window. Based on a 1300+ patient study, the use of molecular-guided therapeutic choices resulted in substantial clinical improvements to both healing rates and healing days as compared to culture-guided choices.

MicroGenDX qPCR+NGS is superior to culture and PCR-only for diagnosis and treatment of chronic or stalled wounds

Standard CulturePCR OnlyMicroGenDX qPCR+NGS

  • Often reports “mixed skin flora” results

  • Underestimates anaerobic bacteria, fungi, VBNC, biofilms

  • Only 15%-30% accuracy finding dominant species


  • Up to 17 antimicrobial resistance genes detected represent the in vivo resistance potential of entire community (polymicrobial/biofilm)


  • Detects all bacteria and fungus present in sample — without bias — matching them to a database of 50,000+ species

  • 99.2% accuracy, listing species by relative abundance

  • Susceptibility represents a single bacterium’s in vitro resistance — not enhanced resistance of in vivo biocommunity


  • Up to 17 antimicrobial resistance genes detected represent the in vivo resistance potential of entire community (polymicrobial/biofilm)

  • Constrained by transportation protocols, growth media, culture preparation, and growth conditions

  • Highly variable turnaround for different bacteria and up to four weeks for fungi


  • 24-48 hours turnaround time, minimally affected by transport time or temperature


  • Comprehensive results with sufficient DNA, and minimally affected by transport time or temperature

  • Rapid return of most comprehensive results — qPCR in 24-48 hours, and NGS in 3.5 days for all species in the sample

  • Costly for polymicrobial, anaerobic, or fungal isolations


  • Same low cost per patient/incident, regardless of the number of microbes detected

MicroGenDX qPCR+NGS also has superior diagnostic capabilities for nail infections

toenail infection

Combining qPCR and NGS offers greater speed and sensitivity, and more reliable speciation, than PAS/GMS or culture.

“As clinicians we can all generally agree that in order to provide the best treatment, we need to understand the organism that we’re dealing with. With MicroGenDX DNA sequencing, we can do this for nail pathogens and create a targeted DNA therapy that is specific to the nail.” — Beth Pearce, DPM

NGSqPCRPAS/GMSCulture

  • 3.5 days

  • >90% sensitivity

  • Genus/species identification with curated database of 50K+ microbes


  • 24-48 hours

  • >90% sensitivity

  • No genus/species identification beyond limited panel


  • 1–3 days

  • ~80% sensitivity

  • No genus/species identification


  • 4–6 weeks

  • <60% sensitivity

  • Limited genus/species identification

References

  1. van Asten S A V, La Fontaine J, et al. The microbiome of diabetic foot osteomyelitis, European Journal of Clinical Microbiology & Infectious Diseases. 2016; 35):293-298. doi: 10.1007/s10096-015-2544-1
  2. Joyce A, Gupta A, et al. Fungal Diversity and Onychomycosis – An Analysis of 8,816 Toenail, Journal of the American Podiatric Medical Association. 2019 Jan;109(1):57-63. doi: 10.7547/17-070
  3. Chadwick P. Fungal infection of the diabetic foot: The often ignored complication. The Diabetic Foot Journal 16: 102–7, 2013
  4. Dowd S E et al Molecular Diagnostics and personalized medicine in wound care: assessment of outcomes. Journal of Wound Care. 2011; 20: 5, 232-239
  5. 2009-2020 College of American Pathologists proficiency data
Show References

PATIENT TYPES:

Chronic wounds

Nail Infections

NGS offers more accurate diagnosis of osteomyelitis in the diabetic foot

Analyzing 34 bone samples from patients with moderate to severe foot infection, 16s rRNA NGS sequencing detected significantly more anaerobes (87% vs 23%, p=0.001) and more Gram-positive bacilli than culture. This suggests that anaerobic and fastidious organisms play a more significant role in osteomyelitis than previously believed.
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qPCR + next-gen sequencing helps prevent foot infections from advancing to ulceration in diabetic patients

The presence of fungal nail and skin infections in the diabetic foot can potentially play a role in the pathogenesis of a foot ulceration. Literature suggests that there is a high risk of secondary bacterial infection.

qPCR+NGS has the capability of identifying fungal and bacterial organisms present in the specimen — along with their estimated percentages — in 3.5 days.

Fungi present in less than 50% of 8,816 nail samples

fungi-pie-chart
  • 34% of clinically suspicious nail samples contained only bacterial species
  • Trichophyton rubrum was present in 40% of fungus-positive samples
  • MicroGenDX has processed over 30,000 nail samples, and our analysis supports these findings

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“We can have the answers back in a few days. That makes a huge difference – because we can start treating those patients without guessing about the antibacterial, antifungal protocol.”

– Lyle Haskell, DPM

Podiatrist, North Texas Foot Group, Allen, TX