Table 2.
Comparative Analysis of Clinical and Microbiological (Phenotypic and Genotypic) Characteristics Between Prosthetic Joint Infections With Onset of Symptoms <30 Days After Surgery and Prosthetic Joint Infections With Onset of Symptoms in the 30–90 Days After Surgery
| Postsurgical <30 d (n = 30), No. (%) | Postsurgical 30–90 d (n = 15), No. (%) | P | |
|---|---|---|---|
| Baseline features | |||
| Sex (men) | 10 (33.3) | 5 (33.3) | 1.000 |
| Age, mean ± SD, y | 76.1 ± 12.8 | 70.4 ± 16.2 | .201 |
| Diabetes mellitus | 4 (13.3) | 4 (26.7) | .410 |
| Chronic renal impairment | 5 (16.7) | 1 (6.7) | .647 |
| Rheumatoid arthritis | 2 (6.7) | 1 (6.7) | 1.000 |
| Prosthesis location (knee) | 10 (33.3) | 8 (53.3) | .197 |
| Prosthesis revision | 6 (20.0) | 3 (20.0) | 1.000 |
| Clinical presentation | |||
| Polymicrobial infection | 5 (16.7) | 3 (20.0) | 1.000 |
| Bacteremia | 4 (13.3) | 2 (13.3) | 1.000 |
| Temperature >37ºC | 11 (36.7) | 5 (33.3) | .826 |
| Sinus tract | 4 (13.3) | 3 (20.0) | .670 |
| Leukocytes, mean ± SD,a ×109/L | 10.2 ± 5.4 | 10.7 ± 5.5 | .779 |
| C-reactive protein, mean ± SD,a mg/L | 121.7 ± 120.4 | 140.5 ± 128.9 | .864 |
| Surgical management | |||
| DAIR | 21 (70.0) | 12 (80.0) | .722 |
| Antimicrobial resistance | |||
| Oxacillin | 5 (16.7) | 4 (26.7) | .454 |
| Levofloxacin | 5 (16.7) | 4 (26.7) | .454 |
| Rifampin | 1 (3.3) | 0 (0.0) | 1.000 |
| Vancomycin MIC ≥1.5 mg/L | 1 (3.3) | 0 (0.0) | 1.000 |
| Phenotypic characteristics | |||
| agr functionality | |||
| Negative | 9 (30.0) | 4 (26.7) | |
| Weak | 5 (16.7) | 2 (13.3) | 1.000 |
| Strong | 16 (53.3) | 9 (60.0) | |
| β-hemolysis | 27 (90.0) | 15 (100.0) | .540 |
| Biofilm formation, mean ± SD, OD 595 nm | 0.13 ± 0.15 | 0.13 ± 0.09 | .682 |
| Molecular epidemiology | |||
| Clonal complex | |||
| CC5 | 9 (30.0) | 6 (40.0) | |
| CC15 | 2 (6.7) | 2 (13.3) | |
| CC30 | 5 (16.7) | 0 (0.0) | .462 |
| CC45 | 6 (20.0) | 2 (13.3) | |
| Other | 8 (26.7) | 5 (33.3) | |
| agr group | |||
| agr I | 9 (30.0) | 4 (26.7) | |
| agr II | 10 (33.3) | 8 (53.3) | .381 |
| agr III | 11 (36.7) | 3 (20.0) |
Abbreviations: CC, clonal complex; DAIR, debridement, antibiotics, and implant retention; MIC, minimum inhibitory concentration; OD, optical density.
aData obtained at diagnosis, before the performance of surgical treatment (either debridement or prosthesis removal).