Table 4.

Patients with concordant false-negative and discordant results.

DiagnosisAgreementPathogenesisReceived Antibiotics before SamplingPCR ResultMicrocalorimetrySF CultureIntraoperative Tissue Cultures
Septic arthritisConcordant false-negative resultsHematogenousYesE. coli
PostinterventionalNoS. epidermidis, F. magna
PostinterventionalYesC. acnes (3/5)
Discordant resultsHematogenousNo+S. dysgalactiaeND
HematogenousYes+S. pneumoniae*S. pneumoniae*
PostinterventionalNo+S. aureusS. aureus
PostinterventionalNo+S. aureusND
HematogenousNoS. agalactiaeS. agalactiaeS. agalactiae
PostinterventionalNoS. pyogenesS. dysgalactiaeS. dysgalactiae
PostinterventionalNoC. clostridioforme*C. clostridioforme*
ContiguousYes+S. aureus
Noninfectious arthritisDiscordant resultsOsteoarthritisNoC. acnesND
PosttraumaticNoC. acnesND
UnknownNoK. pneumoniaeND
  • * Microorganisms not included in the PCR test panel and therefore not detectable by this method. −: negative result; +: positive result; ND: not done (i.e., no subsequent surgery was performed); SF: synovial fluid; E. coli: Escherichia coli; S. epidermidis: Staphylococcus epidermidis; F. magna: Finegoldia magna; C. acnes: Cutibacterium acnes; S. dysgalactiae: Streptococcus dysgalactiae; S. pneumoniae: Streptococcus pneumoniae; S. aureus: Streptococcus aureus; S. agalactiae: Streptococcus agalactiae; S. pyogenes: Streptococcus pyogenes; C. clostridioforme: Clostridium clostridioforme; K. pneumoniae: Klebsiella pneumoniae.