Article Figures & Data
Figures
- FIG 1
Flow diagram shows the patient selection and allocations. Numbers in brackets refer to patients, but numbers of cases are also indicated due to some patients being admitted more than once.
- FIG 2
Days of incubation until growth by type of specimen (5-STB, five soft-tissue biopsy specimens; JF, joint fluid; PC, prosthetic components; SW, swabs from the prosthesis, collected in situ; BB, bone biopsy specimen). Incubation was planned for 14 days but occasionally was extended due to weekends and holidays.
- FIG 3
Days to positive culture for the first specimen type (black columns) and subsequent specimen types (hatched).
- FIG 4
Contribution of specimen types to the diagnosis of prosthetic joint infection. (A) Thirty-five cases were diagnosed based on positive cultures of the minimum set comprising tissue biopsy specimens (5-STB), prosthetic components (PC), and joint fluid (JF). (B) A subgroup of 28 cases was evaluated based on all specimen types. It is apparent that neither the bone biopsy specimen (BB) nor the prosthetic swab (in situ) (SW) culture contributed independently to the diagnosis. *, one case diagnosis was supported by next-generation sequencing; **, one case showed a negative result in the culture of joint fluid; ***, one case showed negative results in the culture of prosthetic components; ****, in four cases, only one or two specimen types contributed to the culture-positive findings.
Tables
- TABLE 1
Diagnostic accuracy measured by likelihood ratios
Specimen,c culture duration (days) or 16S rRNA sequencing No. of cases with a positive test/no. of cases tested LRa PJI (n = 42) AF (n = 66) Positive (95% CI) Negative (95% CI) 5-STB, 6 31/42 0/66 Infinityb 0.3 (0.2–0.4) 5-STB, 14 37/42 0/66 Infinity 0.1 (0.05–0.3) JF, 6 26/39 1/57 38 (5–269) 0.3 (0.2–0.5) JF, 14 34/39 2/56 24 (6–96) 0.1 (0.06–0.3) PC, 6 24/37 1/60 39 (5–276) 0.4 (0.2–0.6) PC, 14 33/37 5/60 11 (5–25) 0.1 (0.05–0.3) SW (in situ), 6 9/32 0/59 Infinity 0.7 (0.6–0.9) SW (in situ), 14 16/32 2/59 15 (4–60) 0.5 (0.4–0.7) BB, 6 9/32 0/54 Infinity 0.8 (0.7–0.9) BB, 14 13/32 1/54 22 (3–160) 0.6 (0.5–0.8) Periprosthetic tissue, 16S rRNA sequencing 8/32 0/53 Infinity 0.8 (0.6–0.9) Synovial fluid, 16S rRNA sequencing 25/35 1/65 46 (7–328) 0.3 (0.2–0.5) PC, 16S rRNA sequencing 32/37 1/64 55 (8–389) 0.1 (0.06–0.3) SW (in situ), 16S rRNA sequencing 15/34 4/52 6 (2–16) 0.6 (0.4–0.8) BB, 16S rRNA sequencing 4/29 2/47 3 (0.6–17) 0.9 (0.8–1.0) - TABLE 2
Infecting microorganisms in prosthetic joint infections in hips and knees
Microorganism No. of organisms found in culturea (n = 39) No. of organisms determined by 16S rRNA sequencing (n = 33) Total Subgroup Polymicrobial 11 5 Staphylococcus spp. 14 16 S. aureus 7 S. epidermidis 2 S. lugdunensis 3 S. capitis 1 CoNS, others 1 Streptococcus spp. 4 6 Hemolytic streptococcus group Cb 2 Hemolytic streptococcus group Gb 2 Enterococcus faecalis 3 2 Escherichia coli 2 Pseudomonas aeruginosa 1 Salmonella serovar Dublin 1 1 Propionibacterium spp. 2 2 P. acnes 2 Finegoldia magna 1 1 ↵a Culturing showed positive results in 39 cases, and sequencing showed positive results in 33 cases. Due to the limited resolution in the 16S rRNA sequencing results, it was not possible to differentiate between species within the genera Staphylococcus, Streptococcus, and Propionibacterium.
↵b The hemolytic streptococci all were identified in culture as Streptococcus dysgalactiae.
Supplemental material
- Supplemental file 1 -
Text S1 (Detailed culture methods)
PDF, 193K
- Supplemental file 2 -
Table S2 (Overview of culturing and molecular data)
XLSX, 23K
- Supplemental file 3 -
Text S3 (Background subtraction in 16S amplicon data analysis)
PDF, 85K
- Supplemental file 1 -
