Diagnosing Biofilm Infections

Polymicrobial infections are associated with poorer outcomes, but are vastly underestimated by culture methods

Biofilms foster tolerance to both antibiotics and host immune defenses, and multiple factors complicate biofilm chronic joint infection diagnosis and therefore treatment, including:

  • Biofilm growth characteristics
  • Sampling tools and techniques
  • Inherent limitations of culture — such as difficulty growing biofilms, VNBC bacteria, and delayed incubation of specimens

With some 80% of PJI associated with polymicrobial biofilms, MicroGenDX is working hard to provide you the best tools for PJI diagnosis. Read More

Biofilm growth characteristics

  • Biofilms growing on implant or tissue surfaces may be limited to one area or proliferate to multiple areas, so full coverage sampling is necessary to capture the diverse microbial community at the site
  • When biofilms mature, cells disperse from the original microcolony and can also be detected in synovial fluid — however, the low presence of dispersal in synovial fluid alone may lead to negative results

The inherent limitations of culture

  • Bacteria from biofilms can exhibit impaired growth in culture — even when the species involved are readily culturable, and permissive conditions are used
  • Human pathogens can resuscitate from a VBNC state without losing their virulence after escaping culture detection
  • Bacteria viability can be affected by delayed specimen incubation: Over 50% of revision specimens are incubated outside of the 2-hr window required by protocol

Sampling tools and techniques

How to Collect OrthoKey Surgery

Full sampling coverage provides best results: implants, medial and lateral gutters, as well as the intramedullary canal are all potential biofilm growth areas that will need to be swabbed. Proper sampling technique is critical for accurate and actionable OrthoKEY results. View videos


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  2. Taha M, Abdelbary H, et al. New Innovations in the Treatment of PJI and Biofilms—Clinical and Preclinical Topics. Curr Rev Musculoskelet Med. 2018 Sep; 11(3): 380–388. 1007/s12178-018-9500-5
  3. Blevins K M, GoswamiK, ParviziThe Journey of Cultures Taken During Revision Joint Arthroplasty: Preanalytical Phase. J Bone Jt Infect. 2019 May 21;4(3):120-125. doi: 10.7150/jbji.32975. eCollection 2019
  4. Li L, Mendis N, et al. The importance of the viable but non-culturable state in human bacterial pathogens. t Microbiol. 2014 Jun 2;5:258. doi: 10.3389/fmicb.2014.00258
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