The Case for NGS
The emerging gold standard for diagnosing chronic joint infection
Second generation 16S/ITS DNA sequencing produces data in vastly larger amounts, at significantly lower cost, in shorter time, and with less manual intervention than previous sequencing methods.
Unlike polymerase chain reaction (PCR), NGS is hypothesis-free and does not rely on a predetermined panel of PCR primer targets. NGS is capable of characterizing all microbial DNA present within a clinical sample and providing a complete picture of the microbial profile, without the need for preconceived ideas of the possible responsible pathogens.
MicroGenDX’s NGS searches against a curated microbial database of over 50,000 species for a match — including bacteria, yeast, and fungi — without the need for additional individual testing.
“We are standing at a very critical historic moment when molecular technologies can help us detect infecting organisms. NGS picks up organisms when cultures are negative and also provide us with the information much faster so during a critical period you are treating the patient with the right antibiotics. Mycobacterm abscesses is not an organism that we usually treat. Not having that information in your hands for 21 days…that could compromise the care of that patient. That is critical information.”
– Dr. Javad Parvizi, Orthopedic Surgeon, Director of Clinical Research at the Rothman Institute
Where does NGS testing fit into your orthopedic practice?
Aspiration
In conjunction with culture, MicroGenDX OrthoKEY Clinic rapidly confirms the likelihood of infection and potential pathogens using synovial biomarkers and NGS.
- Biofilms on hardware will shed microbes into fluid
- The more fluid provided, the greater potential for DNA reads – 2ml minimum, 2x8ml maximum
- Biomarker and resistance gene results in 24-48 hours, NGS sequencing results in 3.5 days
- Review results on the PJIDx diagnostic app
I&D Washout
OrthoKEY Surgery rapidly and accurately identifies multiple species of microbes using synovial biomarkers and NGS.
- Allows for more targeted post-op antimicrobial selection
- If a revision is required, antimicrobials for the spacer can be targeted to the exact species
- Biomarker and resistance gene results in 24-48 hours, NGS sequencing results in 3.5 days
- Review results on the PJIDx diagnostic app
Revision
OrthoKEY Surgery can detect microbes missed by standard culture and reduce potential revision failure.
- Detects exact species for targeted antimicrobial selection
- Biomarker and resistance gene results in 24-48 hours, NGS sequencing results in 3.5 days
- Review results on the PJIDx diagnostic app
Using both NGS and culture together in PJI treatment can reduce revision failure
In a 15-center study, at 2-year follow-up of 777 revision hip and knee procedures, 139 (18%) failed revision, confirmed by culture. At the genus level, the same organisms present at failure were detected by NGS at revision surgery 67% of the time, compared to 19.5% by culture.
Only 8.6% of failure had negative NGS results at revision surgery. By leveraging NGS results, you can reduce revision failure.
Guidelines and studies (see references below) also suggest that up to five samples are required to be cultured in order to achieve optimal results. From a cost perspective, this additive cost of culturing samples makes NGS a favorable choice.
NGS detects pathogens culture doesn’t
A 62-year old patient with infected left total knee and systemic sepsis was referred to the Rothman Institute. Three separate cultures – synovial fluid and tissues of the infected knee – were all negative. NGS technology identified Streptococcus canis, an oral pathogen from dogs in this patient’s sample. His dog had been licking his leg wound. The patient recovered with no sign of infection at six-month follow-up.
