TABLE 1

Pathogen-specific sensitivities of the BCID panel, culture, 16S rRNA gene PCR, 10-assay PCR panel, and PCR-ESI/MS

Pathogen (no. of isolates)No. of isolates detected/total (% sensitivity)
Sonicate fluid culture (>20 CFU/10 ml)eIntraoperative tissue or fluid culture (≥2 specimens)Preoperative synovial fluid cultureFilmArray BCIDe16S rRNA gene PCRe10-assay real-time PCR panelePCR-ESI/MSe
Pathogensi represented in BCID panela
    Candida albicans (2)1/2 (50)1/2 (50)1/1 (100)2/2 (100)NAhNA1/2 (50)
    Enterobacter cloacae (1)0/1 (0)0/1 (0)0/1 (0)1/1 (100)0/1 (0)1/1 (100)1/1 (100)
    Escherichia coli (4)3/4 (75)4/4 (100)2/4 (50)4/4 (100)4/4 (100)4/4 (100)3/4 (100)
    Enterococcus species (8)8/8 (100)6/8 (75)5/5 (100)6/8 (75)b6/8 (75)8/8 (100)5/8 (60)
    Streptococcus agalactiae (3)2/3 (67)2/3 (67)1/1 (100)3/3 (100)3/3 (100)3/3 (100)3/3 (100)
    Group C Streptococcus species (1)1/1 (100)1/1 (100)NDg1/1 (100)1/1 (100)1/1 (100)1/1 (100)
    Group G Streptococcus species (1)1/1 (100)1/1 (100)0/1 (0)1/1 (100)1/1 (100)1/1 (100)0/1 (0)f
    Klebsiella pneumoniae (1)0/1 (0)0/1(0)ND1/1 (100)1/1 (100)1/1 (100)0/1 (0)
    Pseudomonas aeruginosa (4)3/4 (75)4/4 (100)1/1 (100)2/4 (50)4/4 (100)4/4 (100)3/4 (75)
    Serratia species (1)0/1 (0)0/1 (0)0/1 (0)0/1 (0)1/1 (100)1/1 (100)1/1 (100)
    Staphylococcus aureus (20)16/20 (80)19/20 (95)7/9 (78)18/20 (90)c14/20 (70)17/20 (85)19/20 (95)
    SCN (40)d32/40 (83)33/40 (33)21/28 (75)20/37 (54)d33/39 (85)35/38 (92)34/40 (85)
    Viridans group streptococci (2)1/2 (50)1/2 (100)0/1 (0)1/2 (50)1/2 (50)2/2 (100)2/2 (100)
Pathogensj not represented in BCID panel
    Abiotrophia/Granulicatella species (2)2/2 (100)2/2 (100)0/1 (0)NA1/2(50)1/2 (50)1/2 (50)
    Actinomyces species (4)3/4 (75)2/4 (50)1/1 (100)NA1/4 (25)3/4 (75)1/4 (25)
    Capnocytophaga species (1)1/1 (100)1/1 (100)1/1 (100)NA0/1 (0)NA1/1 (100)
    Corynebacterium species (4)1/4 (25)3/4 (75)1/4 (25)NA1/4 (25)1/4 (25)0/4 (0)
    Finegoldia magna (6)6/6 (100)5/6 (83)0/4 (0)NA3/5(60)6/6 (100)4/6 (67)
    Mycobacterium abscessus (1)0/1 (0)1/1 (100)1/1 (100)NA0/1 (0)NA0/1 (0)
    Prevotella melaninogenica (1)1/1 (100)1/1 (100)NDNA1/1 (100)NA1/1 (100)
    Propionibacterium acnes (5)3/5 (60)2/5 (40)2/4 (50)NA3/5 (60)3/5 (60)5/5 (100)
    Veillonella species (1)0/1 (0)1/1 (100)NDNA0/1 (0)NA0/1 (0)
  • a The BCID panel targets Enterococcus species, Listeria monocytogenes, Staphylococcus species (including a specific assay for S. aureus), Streptococcus species (including specific assays for Streptococcus agalactiae, Streptococcus pyogenes, and Streptococcus pneumoniae), Acinetobacter baumannii, Haemophilus influenzae, Neisseria meningitidis, Pseudomonas aeruginosa, Enterobacteriaceae (including specific assays for Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus species, and Serratia marcescens), Candida albicans, Candida glabrata, Candida krusei, Candida parapsilosis, Candida tropicalis, mecA, vanA/B, and blaKPC. PJI was defined as the presence of one or more of the following: synovial fluid or periprosthetic purulence, sinus tract communicating with the prosthesis, and/or periprosthetic tissue histopathology with acute inflammation. Significant cultures were defined as (i) two or more intraoperative periprosthetic tissue and/or synovial fluid samples with the same organism, (ii) a positive preoperative synovial fluid culture and an intraoperative culture that yielded the same organism, and/or (iii) sonicate fluid cultures with an organism detected at a concentration of ≥20 CFU/10 ml. Organisms were considered true pathogens if they were detected in a PJI case and (i) met the definition of a significant culture, (ii) were detected in at least one culture sample and by at least one molecular assay, or (iii) were detected by two or more different molecular assays.

  • b One hundred percent concordance with phenotypic testing: two vanA/B-positive isolates, both vancomycin resistant phenotypically; four vanA/B-negative isolates, all vancomycin susceptible phenotypically.

  • c One hundred percent concordance with phenotypic testing: six mecA-positive isolates, all oxacillin resistant phenotypically.

  • d For the BCID panel, only 37 specimens were assessed for SCN sensitivity, as S. aureus was codetected in three specimens.

  • e PCR-ESI/MS was performed with unconcentrated sonicate fluid; the BCID panel, the 16S rRNA gene PCR assay, the 10-assay PCR panel, and culture were performed with concentrated sonicate fluid.

  • f Identified by PCR-ESI/MS as Streptococcus pyogenes, with the next best match a group G Streptococcus species.

  • g ND, not done.

  • h NA, not applicable.

  • i From 70 cases of PJI.

  • j From 14 cases of PJI.