Introduction
Materials and methods
Study definitions and statistical analyses
Results
Blood culture findings
Factors associated with blood culture sampling
Variable | All (n = 460) | Blood cultures drawn (n = 258) | Blood cultures not drawn (n = 202) | OR (95% CI) | P value | Multivariate logistic regression analysis | |
---|---|---|---|---|---|---|---|
OR (95% CI) | P value | ||||||
Male gender | 280 (60.9) | 168 (65.1) | 112 (55.4) | 1.5 (1.0–2.2) | 0.035 | 1.2 (0.8–1.9) | 0.337 |
Age, years [mean (SD)] | 67.4 (18.1) | 66.8 (17.5) | 68.1 (19.0) | 0.465 | |||
Diabetes | 187 (40.7) | 120 (46.5) | 67 (33.2) | 1.7 (1.2–2.6) | 0.004 | 1.9 (1.2–2.9) | 0.008 |
Peripheral vascular disease | 135 (29.3) | 62 (24.0) | 73 (36.1) | 0.6 (0.4–0.8) | 0.005 | 0.5 (0.3–0.8) | 0.007 |
Congestive heart disease | 43 (9.3) | 23 (8.9) | 20 (9.9) | 0.9 (0.5–1.7) | 0.718 | ||
Respiratory disease | 34 (7.4) | 22 (8.5) | 12 (5.9) | 1.5 (0.7–3.1) | 0.293 | ||
Chronic renal disease | 32 (7.0) | 21 (8.1) | 11 (5.4) | 1.5 (0.7–3.3) | 0.260 | ||
Liver disease | 23 (5.0) | 14 (5.4) | 9 (4.5) | 1.2 (0.5–2.9) | 0.673 | ||
HIV infection | 7 (1.5) | 5 (1.9) | 2 (1.0) | 2.0 (0.4–10.3) | 0.474 | ||
Any disease with immune system impairment | 14 (3.0) | 6 (2.3) | 8 (4.0) | 0.6 (0.2–1.7) | 0.311 | ||
Malignancy | 36 (7.8) | 19 (7.4) | 17 (8.4) | 0.9 (0.4–1.7) | 0.677 | ||
Alcohol abuse | 40 (8.7) | 28 (10.9) | 12 (5.9) | 1.9 (1.0–3.9) | 0.064 | 1.4 (0.6–3.1) | 0.475 |
Intravenous drug use | 32 (7.0) | 15 (5.8) | 17 (8.4) | 0.7 (0.3–1.4) | 0.276 | ||
No. of co-morbidities ≥ 2 | 171 (37.2) | 98 (38.0) | 73 (36.1) | 1.1 (0.7–1.6) | 0.684 | ||
Hospitalisation < 3 months | 84 (18.3) | 44 (17.1) | 40 (19.8) | 0.8 (0.5–1.3) | 0.449 | ||
Invasive surgery < 3 months | 71 (15.4) | 33 (12.8) | 38 (18.8) | 0.6 (0.4–1.1) | 0.076 | ||
Antibiotic treatment before dg | 128 (27.8) | 58 (22.5) | 70 (34.7) | 0.5 (0.4–0.8) | 0.004 | 0.7 (0.4–1.1) | 0.115 |
Abscess | 183 (39.8) | 91 (35.3) | 92 (45.5) | 0.7 (0.4–1.0) | 0.025 | ||
Cellulitis/fasciitis (no abscess or ulcer) | 193 (42.0) | 128 (49.6) | 65 (32.2) | 2.1 (1.4–3.0) | < 0.001 | 1.6 (1.0–2.5) | 0.052 |
Decubitus or pressure ulcer | 14 (3.0) | 6 (2.3) | 8 (4.0) | 0.6 (0.2–1.7) | 0.311 | ||
Diabetic foot/leg ulcer | 66 (14.3) | 31 (12.0) | 35 (17.3) | 0.7 (0.4–1.1) | 0.107 | ||
Peripheral vascular disease ulcer | 53 (11.5) | 21 (8.1) | 32 (15.8) | 0.5 (0.3–0.8) | 0.010 | ||
Post-surgical wound | 79 (17.2) | 35 (13.6) | 44 (21.8) | 0.6 (0.3–0.9) | 0.020 | 0.4 (0.2–0.8) | 0.005 |
Post-traumatic wound | 50 (10.9) | 30 (11.6) | 20 (9.9) | 1.2 (0.7–2.2) | 0.555 | ||
Anatomical site of the infection | |||||||
Head | 5 (1.1) | 4 (1.6) | 1 (0.5) | 3.2 (0.4–28.5) | 0.391 | ||
Hand | 9 (2.0) | 4 (1.6) | 5 (2.5) | 0.6 (0.2–2.3) | 0.515 | ||
Trunk | 142 (30.9) | 73 (28.3) | 69 (34.2) | 0.8 (0.5–1.1) | 0.177 | ||
Upper extremities | 52 (11.3) | 33 (12.8) | 19 (9.4) | 1.4 (0.8–2.6) | 0.255 | ||
Lower extremities | 284 (61.7) | 167 (64.7) | 117 (57.9) | 1.3 (0.9–1.9) | 0.136 | 1.4 (0.8–2.2) | 0.214 |
Duration of symptoms before the diagnosis | |||||||
< 2 days | 130 (28.3) | 97 (37.6) | 33 (16.3) | 3.1 (2.0–4.8) | < 0.001 | 3.0 (1.8–5.2) 1 | < 0.001 |
2–7 days | 230 (50.0) | 129 (50) | 101 (50.0) | 1.0 (0.7–1.4) | > 0.99 | ||
> 7 days | 90 (19.6) | 29 (11.2) | 61 (30.2) | 0.3 (0.2–0.5) | < 0.001 | ||
C-reactive protein (CRP) mg/L (n = 425) | |||||||
1st day CRP > 150 | 214 (50.4) | 139 (57.0) | 75 (41.4) | 1.9 (1.3–2.8) | 0.002 | 1.8 (1.2–2.8) | 0.006 |
1st day CRP [median (IQR)] | 157 (81–252) | 181 (91–266) | 130 (73–210) | 0.003 |
Factors associated with blood culture positivity
Variable | All (n = 258) | Positive blood cultures (n = 61) | Negative blood cultures (n = 197) | OR (95% CI) | P value | Multivariate logistic regression analysis | |
---|---|---|---|---|---|---|---|
OR (95% CI) | P value | ||||||
Demographics and co-morbidities | |||||||
Male gender | 168 (65.1) | 42 (68.9) | 126 (64.0) | 1.2 (0.7–2.3) | 0.484 | ||
Age > 60 years | 165 (64.0) | 40 (65.6) | 125 (63.5) | 1.1 (0.6–2.0) | 0.763 | ||
Age, years [mean (SD)] | 66.8 (17.5) | 66.2 (16.4) | 67.0 (17.9) | 0.734 | |||
Diabetes | 120 (46.5) | 27 (44.3) | 93 (47.2) | 0.9 (0.5–1.6) | 0.687 | ||
Peripheral vascular disease | 62 (24.0) | 15 (24.6) | 47 (23.9) | 1.0 (0.5–2.0) | 0.907 | ||
Congestive heart disease | 23 (8.9) | 2 (3.3) | 21 (10.7) | 0.3 (0.1–1.2) | 0.077 | 0.2 (0.05–1.04) | 0.057 |
Respiratory disease | 22 (8.5) | 9 (14.8) | 13 (6.6) | 2.5 (1.0–6.0) | 0.046 | 2.2 (0.8–5.8) | 0.133 |
Chronic renal disease | 21 (8.1) | 3 (4.9) | 18 (9.1) | 0.5 (0.1–1.8) | 0.423 | ||
Liver disease | 14 (5.4) | 6 (9.8) | 8 (4.1) | 2.6 (0.9–7.7) | 0.104 | ||
HIV infection | 5 (1.9) | 1 (1.6) | 4 (2.0) | 0.8 (0.1–7.3) | > 0.999 | ||
Any disease with immune system impairment | 6 (2.3) | 3 (4.9) | 3 (1.5) | 3.3 (0.7–17.0) | 0.146 | ||
Cancer/malignancy | 19 (7.4) | 5 (8.2) | 14 (7.1) | 1.2 (0.4–3.4) | 0.781 | ||
Alcohol abuse | 28 (10.9) | 15 (24.6) | 13 (6.6) | 4.6 (2.1–10.4) | < 0.001 | 5.5 (2.3–13.2) | < 0.001 |
Intravenous drug use | 15 (5.8) | 3 (4.9) | 12 (6.1) | 0.8 (0.2–2.9) | > 0.999 | ||
No. of co-morbidities ≥ 2 | 98 (38.0) | 26 (42.6) | 72 (36.5) | 1.3 (0.7–2.3) | 0.393 | ||
Hospitalisation < 3 months | 44 (17.1) | 12 (19.7) | 32 (16.2) | 1.3 (0.6–2.6) | 0.534 | ||
Invasive surgery < 3 months | 33 (12.8) | 7 (11.5) | 26 (13.2) | 0.9 (0.4–2.1) | 0.725 | ||
Antibiotic treatment before dg | 58 (22.5) | 14 (23) | 44 (22.3) | 1.0 (0.5–2.0) | 0.920 | ||
Clinical features | |||||||
Abscess | 91 (35.3) | 15 (24.6) | 76 (38.6) | 0.5 (0.3–1.0) | 0.046 | ||
Cellulitis/fasciitis | 128 (49.6) | 37 (60.7) | 91 (46.2) | 1.8 (1.0–3.2) | 0.048 | 1.6 (0.8–3.2) | 0.162 |
Decubitus or pressure ulcer | 6 (2.3) | 1 (1.6) | 5 (2.5) | 0.6 (0.1–5.6) | > 0.999 | ||
Diabetic foot/leg ulcer | 31 (12.0) | 9 (14.8) | 22 (11.2) | 1.4 (0.6–3.2) | 0.452 | ||
Peripheral vascular disease ulcer | 21 (8.1) | 3 (4.9) | 18 (9.1) | 0.5 (0.1–1.8) | 0.423 | ||
Post-surgical wound | 35 (13.6) | 5 (8.2) | 30 (15.2) | 0.5 (0.2–1.3) | 0.161 | ||
Post-traumatic wound | 30 (11.6) | 10 (16.4) | 20 (10.2) | 1.7 (0.8–3.9) | 0.184 | ||
Anatomical site of the infection | |||||||
Head | 4 (1.6) | 2 (3.3) | 2 (1.0) | 3.3 (0.5–24.0) | 0.238 | ||
Hand | 4 (1.6) | 1 (1.6) | 3 (1.5) | 1.000 | > 0.999 | ||
Trunk | 73 (28.3) | 10 (16.4) | 63 (32.0) | 0.4 (0.2–0.9) | 0.018 | ||
Upper extremities | 33 (12.8) | 12 (19.7) | 21 (10.7) | 2.1 (0.9–4.5) | 0.066 | ||
Lower extremities | 167 (64.7) | 45 (73.8) | 122 (61.9) | 1.7 (0.9–3.3) | 0.091 | 2.0 (0.98–4.2) | 0.055 |
Duration of symptoms before the diagnosis | |||||||
< 2 days | 97 (37.6) | 28 (45.9) | 69 (35.0) | 1.6 (0.9–2.8) | 0.125 | 1.3 (0.7–2.6)1 | 0.425 |
2–7 days | 129 (50) | 21 (34.4) | 108 (54.8) | 0.4 (0.2–0.8) | 0.005 | ||
> 7 days | 29 (11.2) | 11 (18.0) | 18 (9.1) | 2.2 (1.0-4.9) | 0.055 | ||
C-reactive protein (CRP) mg/L | |||||||
1st day CRP count [median (IQR)] (n = 244) | 181 (91–266) | 201 (97–286) | 170 (89–261) | 0.410 | |||
Highest CRP count [median (IQR)] (n = 256) | 240 (156–320) | 243 (166–331) | 240 (150–311) | 0.465 |
Clinical endpoints in blood culture positivity
Variable | All (n = 258) | Positive blood cultures (n = 61) | Negative blood cultures (n = 197) | Odds ratio (95% CI) | P value |
---|---|---|---|---|---|
Clinical stability within 3 days (n = 223) | 105 (47.1) | 15 (30) | 90 (52) | 0.4 (0.2–0.8) | 0.006 |
Admission to ICU | 51 (19.8) | 20 (32.8) | 31 (15.7) | 2.6 (1.4–5.0) | 0.003 |
Surgical intervention after the diagnosis of cSSSI | 129 (50) | 34 (55.7) | 95 (48.2) | 1.4 (0.8–2.4) | 0.305 |
30-day mortality | 16 (6.2) | 4 (6.6) | 12 (6.1) | 1.1 (0.3–3.5) | > 0.999 |
Streamlining (n = 251) | 26 (10.4) | 14 (23.3) | 12 (6.3) | 4.5 (2.0–10.5) | < 0.001 |
Duration of antimicrobial treatment, days [median (IQR)] (n = 255) | 21 (12–38) | 26 (11.5–46.8) | 20 (12–38) | 0.191 | |
Length of hospital stay, days [median (IQR)] (n = 228) | 15 (8–29) | 19.5 (13–45.3) | 13 (7–23) | < 0.001 |