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Table 2 Baseline characteristics and clinical outcomes of patients with methicillin-susceptible S. aureus bacteremia. Patients received either empiric combination therapy with β-lactam plus vancomycin or empiric β-lactam monotherapy

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-lactam plus vancomycina (n=153) β-lactam monotherapya (n=47) P-value
Ageb 51.3 ± 16.9 58.7 ± 16.1 < 0.01
Males 92 (60.1) 34 (72.3) 0.17
Community-onset 137 (89.5) 36 (76.6) 0.03
Hospital-onset 16 (10.5) 11 (23.4) 0.03
HIV infection 18 (11.8) 2 (4.26) 0.17
Hepatitis C infection 50 (32.7) 11 (23.4) 0.28
Immunocompromised 12 (7.84) 6 (12.8) 0.38
Alcohol or illicit drug abuse 68 (44.4) 14 (29.8) 0.09
Intravenous drug use 54 (35.3) 10 (21.3) 0.08
Charlson comorbidity indexc 3 (1–6) 3 (1–5) 0.30
Pitt bacteremia scorec 1 (0–2) 0 (0–1) < 0.01
Infectious diseases consultation 120 (78.4) 30 (63.8) 0.05
Source of bacteremia
 Central or peripheral line 15 (9.80) 9 (19.1) 0.12
 Skin and soft tissue 25 (16.3) 11 (23.4) 0.28
 Intravenous drug use 43 (28.1) 5 (10.6) 0.02
 Bone or joint infection 15 (9.80) 8 (17.0) 0.19
 Lung 4 (2.61) 2 (4.26) 0.63
 Other 14 (9.15) 5 (10.6) 0.78
 Unknown 37 (24.2) 7 (14.9) 0.23
Infective endocarditis 40 (26.1) 5 (10.6) 0.03
Metastatic complications 66 (43.1) 7 (14.9) < 0.001
Surgical source control 31 (20.3) 12 (25.5) 0.43
Empiric antimicrobials
 Cloxacillin or cefazolin 95 (62.1) 43 (91.5) < 0.0001
 3rd generation cephalosporin 73 (47.7) 7 (14.9) < 0.0001
 Piperacillin-tazobactam 65 (42.5) 4 (8.51) < 0.0001
 Ticarcillin-clavulanic acid 2 (1.31) 1 (2.13) 0.55
 Carbapenem 7 (4.58) 1 (2.13) 0.68
 Daptomycin 0 2 (4.26) 0.05
 Linezolid 1 (0.65) 1 (2.13) 0.42
 Otherd 60 (39.2) 22 (46.8) 1.00
Blood culture time to positivitye 20.3 (16.3–25.3) 19.8 (18.0–27) 0.36
Duration of empiric therapye 55.5 (44.9–73.8) 54.3 (38.8–64.5) 0.08
Duration of definitive therapyf 31 (14–43) 26 (12–40) 0.18
Time to receipt of empiric therapye 1.6 (0.03–6.17) 3.95 (0.58–15.5) 0.08
Time to receipt of β-lactame 2.77 (0.25–13.7) 3.95 (0.58–16.6) 0.74
Time to receipt of cloxacillin or cefazoline 34.8 (21.2–58.4) 13.0 (1.83–23.8) 0.00
Empiric β-lactam exposuree 52.3 (39.8–73.8) 51.7 (38.8–64.5) 0.42
Proportional empiric β-lactam exposureg 100 (86.1–100) 100 (95.2–100) 0.01
Primary outcome
 28-day mortality 14 (9.15) 2 (4.26) 0.37
Secondary outcomes    
 90-day mortality 21 (13.7) 4 (8.51) 0.45
 Recurrent infection at 6 months 5 (3.27) 2 (4.26) 0.67
 Duration of bacteremiae,h 84.8 (52.5–136) 63.4 (30.5–114) 0.03
 ≥ 3 daysh 81 (56.3) 17 (44.7) 0.27
 Hospital length of stayf 26 (13–45) 15 (10–30) < 0.01
  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 as median percentages with interquartile range in parentheses
  8. hData missing for 9 patients in each subgroup