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

Age^b

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 index^c

3 (1–6)

3 (1–5)

0.30

Pitt bacteremia score^c

1 (0–2)

0 (0–1)

< 0.01

Infectious diseases consultation

120 (78.4)

30 (63.8)

0.05

 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

 Cloxacillin or cefazolin

95 (62.1)

43 (91.5)

< 0.0001

 3^rd 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

 Other^d

60 (39.2)

22 (46.8)

1.00

Blood culture time to positivity^e

20.3 (16.3–25.3)

19.8 (18.0–27)

0.36

Duration of empiric therapy^e

55.5 (44.9–73.8)

54.3 (38.8–64.5)

0.08

Duration of definitive therapy^f

31 (14–43)

26 (12–40)

0.18

Time to receipt of empiric therapy^e

1.6 (0.03–6.17)

3.95 (0.58–15.5)

0.08

Time to receipt of β-lactam^e

2.77 (0.25–13.7)

3.95 (0.58–16.6)

0.74

Time to receipt of cloxacillin or cefazolin^e

34.8 (21.2–58.4)

13.0 (1.83–23.8)

0.00

Empiric β-lactam exposure^e

52.3 (39.8–73.8)

51.7 (38.8–64.5)

0.42

Proportional empiric β-lactam exposure^g

100 (86.1–100)

100 (95.2–100)

0.01

 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 bacteremia^e,h

84.8 (52.5–136)

63.4 (30.5–114)

0.03

 ≥ 3 days^h

81 (56.3)

17 (44.7)

0.27

 Hospital length of stay^f

26 (13–45)

15 (10–30)

< 0.01