TABLE 3

Samples with most relevant discrepancies between culture and IS-pro and the associated PacBio and clinical data

Case no.Sample typeDiscrepancyCulture resultaIS-pro resultPacBio resultClinical record
1Infected thoracolumbar osteosynthesis deviceCulture negative, IS-pro positiveNegativeB. fragilisB. fragilisPatient first ameliorated after surgical debridement of osteosynthesis device combined with antibiotics but subsequently declined. Following surgery, presence of B. fragilis in culture was revealed
2Punctate from cervical fluid collection after radical neck dissectionCulture negative, IS-pro positiveNegativeS. mitis group, S. salivarius group, H. parainfluenzae, P. aeruginosa, Bacteroidetes speciesStreptococcus species, Bacteroides speciesPatient recovered after aspiration of fluid and antibiotic treatment
4Punctate from resolving paracolic abscess after left-sided hemicolectomyCulture negative, IS-pro positiveNegativeUnidentified Firmicutes (low signal, <500 RFU)NegativeSample was taken from a resolving paracolic abscess, which was encountered during surgery for a different issue. Patient recovered further under antibiotic treatment
5Persisting delirium and intracerebral soft-tissue massCulture negative, IS-pro positiveNegativeBacteroidetes and Enterobacter species (low signal, <500 RFU)NegativePersistent delirium and elevated infection parameters following recurrent episodes of otitis. Patient did not respond to penicillin, ceftazidime, and voriconazole and died 7 wk after admission
xPulmonary abscessFewer species found in IS-pro than cultureE. faecium, S. aureus, Achromobacter denitrificans, S. marcescensE. faecium, E. faecalis, S. anginosusEnterococcus species, Streptococcus speciesS. aureus found in sputum samples but not in pleural punctate taken 3 wk later. Patient recovered under vancomycin treatment
xPus from spondylodiscitis Th5Fewer species found in IS-pro than cultureMultiple unidentified species, regarded as contaminationStreptococcus bovisnegativeNot available
  • a In four of the five cases with negative culture, patients had been treated with antibiotics. x, the two samples with case number x were the samples in which more species were found by culture than by IS-pro.