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Table 1 Baseline characteristics and clinical outcomes of patients with methicillin-susceptible S. aureus bacteremia. Patients received empiric antimicrobial therapy with either β-lactams or vancomycin

From: Comparison of outcomes in patients with methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia who are treated with β-lactam vs vancomycin empiric therapy: a retrospective cohort study

Patient characteristics β-lactama (n=200) Vancomycina (n=200) P-value
Ageb 53.0 ± 16.9 57.9 ± 18.4 0.01
Males 126 (63.0) 132 (66.0) 0.53
Community-onset 173 (86.5) 158 (79.0) 0.05
Hospital-onset 27 (13.5) 42 (21.0) 0.05
HIV infection 20 (10.0) 16 (8.0) 0.48
Hepatitis C infection 61 (30.5) 55 (27.5) 0.51
Immunocompromised 18 (9.0) 16 (8.0) 0.72
Alcohol or illicit drug abuse 82 (41.0) 71 (35.5) 0.26
Intravenous drug use 64 (32.0) 56 (28.0) 0.38
Charlson comorbidity indexc 3 (1.0–6.0) 4 (1.0–7.0) 0.01
Pitt bacteremia scorec 1 (0–2) 1 (0–2) 0.18
Infectious diseases consultation 150 (75.0) 132 (66.0) 0.05
Source of bacteremia
 Central or peripheral line 24 (12.0) 37 (18.5) 0.09
 Skin and soft tissue 36 (18.0) 24 (12.0) 0.12
 Intravenous drug use 48 (24.0) 39 (19.5) 0.33
 Bone or joint infection 23 (11.5) 13 (6.5) 0.11
 Lung 6 (3.0) 7 (3.5) 1.00
 Other 19 (9.5) 20 (10.0) 1.00
 Unknown 44 (22.0) 60 (30.0) 0.09
Infective endocarditis 45 (22.5) 23 (11.5) < 0.01
Metastatic complications 73 (36.5) 53 (26.5) 0.03
Surgical source control 43 (21.5) 26 (13.0) 0.02
Empiric antimicrobials
 β-lactam 200 (100) 75 (37.5) < 0.0001
 Cloxacillin or cefazolin 138 (69.0) 10 (5.0) < 0.0001
 3rd generation cephalosporin 80 (40.0) 35 (17.5) < 0.0001
 Piperacillin-tazobactam 69 (34.5) 35 (17.5) < 0.001
 Ticarcillin-clavulanic acid 3 (1.5) 1 (0.5) 0.62
 Carbapenem 8 (4.0) 4 (2.0) 0.24
 Vancomycin 153 (76.5) 197 (98.5) < 0.0001
 Daptomycin 2 (1.0) 1 (0.5) 1.00
 Linezolid 2 (1.0) 2 (1.0) 1.00
 Otherd 82 (41.0) 97 (48.5) 0.13
Blood culture time to positivitye 20.2 (16.6–25.5) 18.5 (16.2–23.3) 0.02
Duration of empiric therapye 55.4 (44.2–72.5) 52.1 (39.2–75.7) 0.55
Duration of definitive therapyf 28 (13.0–42.0) 26.5 (11.0–42.0) 0.14
Time to receipt of empiric therapye 1.92 (0.1–6.9) 10.8 (1.4–24.1) < 0.0001
Time to receipt of β-lactame 2.92 (0.3–13.8) 50.5 (4.8–75.5) < 0.0001
Time to receipt of cloxacillin or cefazoline 31.0 (13.8–50.8) 67.8 (50.3–88.0) < 0.0001
Empiric β-lactam exposure 52.3 (39.8–71.9)e
60.6 ± 39.9g
0 (0–16.2)e
9.5 ± 38.5g
< 0.0001
Proportional empiric β-lactam exposure 100 (100–100)h
94.5 ± 46.9i
0 (0–24.5)h
14.0 ± 44.8i
< 0.0001
Primary outcome
 28-day mortality 16 (8.0) 18 (9.0) 0.72
Secondary outcomes
 90-day mortality 25 (12.5) 32 (16.0) 0.32
 Recurrent infection at 6 months 7 (3.5) 8 (4.0) 0.79
 Duration of bacteremiae,j 74.4 (48.3–130) 89.7 (56.7–132) 0.20
 ≥ 3 daysj 98 (53.8) 111 (60.0) 0.25
 Hospital length of stayf 22.5 (12.5–43.0) 22 (13.0–45.0) 0.59
  1. aVariables are displayed as counts and percentages in parentheses unless otherwise specified
  2. bAge is represented as a mean ± standard deviation in years
  3. cVariables are expressed as a median with interquartile range in parentheses
  4. dOther antimicrobials used during empiric and definitive therapy included rifampin, aminoglycosides, fluoroquinolones, macrolides, trimethoprim-sulfamethoxazole, and clindamycin
  5. eVariables are expressed as median hours with interquartile range in parentheses
  6. fVariables are expressed as median days with interquartile range in parentheses
  7. gVariables are expressed a mean ± standard deviation in hours
  8. hVariables are expressed as median percentages with interquartile range in parentheses
  9. iVariables are expressed a mean percentage ± standard deviation
  10. jData missing for 18 and 15 patients in the β-lactam and vancomycin group, respectively