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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