Table 2.
Baseline characteristics of calculated clusters from patients with Staphylococcus aureus bacteremia.
|
Cluster 1 (n = 43) |
Cluster 2 (n = 35) |
Cluster 3 (n = 40) |
Cluster 4 (n = 29) |
Cluster 5 (n = 31) |
p-valueC | |
|---|---|---|---|---|---|---|
| 28-day mortality—N (%) | 5 (11.6%) | 7 (20%) | 4 (10%) | 6 (20.7%) | 7 (22.6%) | 0.453 (0.049*) |
| Age years—median (Q1–Q3)A | 59 (45–69) | 59 (40–71) | 57 (41–71) | 60 (42–67) | 61 (51–81) | 0.463 |
| Male gender—N (%) | 34 (79%) | 24 (67%) | 23 (58%) | 18 (62%) | 22 (71%) | 0.273 |
| BMI—median (Q1–Q3) | 27.4 (23.4–30) | 23 (19.1–28.4) | 24 (21.7–28.4) | 25.3 (22.3–28.6) | 25.7 (23.8–27.7) | 0.118 |
| ICU admission—N (%) | 10 (23%) | 13 (37%) | 9 (23%) | 5 (17%) | 9 (29%) | 0.412 |
| Adequate antibiotic therapy—N (%) B | 41 (95%) | 27 (77%) | 37 (93%) | 28 (97%) | 30 (97%) | 0.034 |
| Biofilm-formation—median (Q1–Q3) | 0.69 (0.56–0.8) | 0.55 (0.44–0.8) | 0.93 (0.7–1.15) | 0.44 (0.34–0.52) | 0.69 (0.57–0.94) | <0.0001 |
| Genetic markers—N (%) | ||||||
| MRSA | 2 (5%) | 8 (23%) | 2 (5%) | 0 (0%) | 1 (3%) | 0.005 |
| fnbA | 41 (95%) | 34 (97%) | 38 (95%) | 28 (97%) | 7 (23%) | <0.0001 |
| fnbB | 0 (0%) | 1 (3%) | 39 (98%) | 0 (0%) | 0 (0%) | <0.0001 |
| clfA | 42 (98%) | 34 (97%) | 40 (100%) | 29 (100%) | 29 (94%) | 0.429 |
| clfB | 43 (100%) | 35 (100%) | 40 (100%) | 29 (100%) | 26 (84%) | 0.0002 |
| fib | 43 (100%) | 1 (3%) | 38 (95%) | 0 (0%) | 2 (6%) | <0.0001 |
| vWbp | 43 (100%) | 34 (97%) | 39 (98%) | 29 (100%) | 25 (81%) | 0.0010 |
| Coagulase gene size—N (%) | ||||||
| 547 bp | 4 (9%) | 2 (6%) | 6 (15%) | 27 (97%) | 3 (10%) | |
| 603 bp | 12 (28%) | 2 (6%) | 31 (78%) | 2 (3%) | 3 (10%) | |
| 660 bp | 17 (40%) | 30 (86%) | 1 (3%) | 0 (0%) | 24 (77%) | 0.0005 |
| 750 bp | 8 (19%) | 1 (3%) | 0 (0%) | 0 (0%) | 1 (3%) | |
| 875 bp | 2 (5%) | 0 (0%) | 1 (3%) | 0 (0%) | 0 (0%) | |
| Laboratory parameters—median (Q1–Q3) | ||||||
| CRP (mg/dL) | 12.4 (8.3–24.3) | 11.9 (6.8–21.9) | 8.4 (3.1–24.9) | 12.1 (4.7–26.4) | 12.8 (6.8–19.4) | 0.576 |
| Leukocytes (G/L) | 9 (6.1–13) | 11.6 (8–16) | 9.7 (4.9–13.9) | 9.8 (5.8–13.7) | 10.2 (7.8–12.9) | 0.777 |
| Platelets (G/L) | 156 (108–241) | 161 (100–331) | 160 (105–245) | 192 (129–272) | 153 (105–217) | 0.662 |
| Hemoglobin (g/dL) | 10.4 (9.2–11.7) | 10.4 (9–12.2) | 10.5 (8.7–12.2) | 10.3 (9.4–12.2) | 10.6 (9.2–12.3) | 0.873 |
| Creatinine (mg/dL) | 1.2 (0.9–1.9) | 1.2 (0.7–2) | 1.2 (0.8–2.4) | 1.03 (0.9–1.7) | 1 (0.8–1.3) | 0.484 |
| Blood urea nitrogen (mg/dL) | 25.6 (15.5–34.4) | 21.3 (14.8–40.9) | 25.4 (10.8–41.9) | 20 (14.3–27.6) | 19.8 (16.2–27) | 0.828 |
| Fibrinogen (mg/dL) | 500 (360–669) | 491 (410–618) | 446 (335–625) | 530 (302–679) | 496 (370–600) | 0.952 |
| Prothrombin time (%) | 68 (55–78) | 73 (43–93) | 76 (46–96) | 68 (49–86) | 75 (45–94) | 0.993 |
| Albumin (g/L) | 29 (26.1–35.6) | 30 (23.4–37.5) | 31.6 (27.1–37.2) | 31.5 (27.2–38.6) | 29.3 (27.2–36.6) | 0.618 |
| Total bilirubin (mg/dL) | 0.7 (0.5–1.3) | 0.7 (0.4–3.3) | 0.7 (0.5–1.2) | 0.6 (0.3–1) | 1 (0.6–1.6) | 0.254 |
BMI, Body Mass Index, ICU: Intensive care unit; MRSA, Methicillin-resistant Staphylococcus aureus; COPD, chronic obstructive pulmonary disease; coa, coagulase; vWbp, von Willebrand factor-binding protein; clfA and clfB, clumping factor A and B; fnbA and fnbB, fibronectin-binding protein A and B; fib, fibrinogen-binding protein; ECDC, European Center of Disease Control; CRP, C-reactive protein.
p-value for comparison of low (clusters 1 and 3) and high (clusters 2, 4, 5) mortality clusters were calculated using one-sided Fisher's exact test.
Q1–Q3: Quartile 1 to Quartile 3.
Adequate antimircobial treatment: defined as the initiation of at least one antimicrobial substance to which the isolated strain showed in vitro susceptibility according to the clinical breakpoints of the European Committee on Antimicrobial Susceptibility Testing (The European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone diameters. Version 9.0, 2019) (EUCAST).
p-values were calculated by use of Kruskal-Wallis test for numeric values and Fisher's exact test for ordinal data.