Table 1 Univariate anaysis of risk factors associated with Serratia marcescens infection or colonzation

Mean gestational age, wk

34

37

0,76*

0,69–0,83

(range; OR per week)

(23–41)

(25–42)

Mean birth weight, g

2235

2986

(range; OR per 500g)

(500–5220)

(400–5850)

0,56*

0.6–0.68

Vaginal delivery

50 (48%)

132 (64%)

Cesarean section

55 (52%)

74 (36%)

1,92*

1.18–3.12

Apgar score after 1 min

6

7

0,84*

0.75–0.93

Prematurity

75 (71%)

74(36%)

5.46*

3.01–9.93

Invasive device

Intubation

35 (33%)

27 (13%)

2,18*

1,55–8,43

Mean duration of intubation, d

8,1

3,7

(range)

(1–61)

(1–24)

1,06

0,93–1,22

CVC

31 (30%)

31 (15%)

2,87*

1,51–5,46

Mean duration of CVC,d

10

7,4

(range)

(1–42)

(1–30)

1,08*

1,02–1,13

Arterial catheter

51 (49%)

45 (22%)

10,44*

4,06–26,83

Peripherial catheter

102 (97%)

160 (78%)

10,18*

3,09–33,53

Nasogastral tube

86 (82%)

88 (43%)

6,86*

3,57–10,07

Parenteral feeding

28 (27%)

25 (12%)

4,72*

2,27–9,8

Breast milk

77 (73%)

179 (87%)

0,37*

0,19–0,71

Antimicrobial therapy

93 (89%)

100 (51%)

10,86*

4,63–25,46

Mean duration of antimicrobial therapy, d

7,5

6,5

1,03

0,98–1,08

(range)

(1–52)

(1–29)

Maternal infection

21 (20%)

45 (24%)

0,84

0,46–1,53

Mean length of stay, d

31

13

1,05*

1,03–1,07

(range)

(3–213)

(2–90)

Surgery

14 (13%)

11 (5%)

2,72*

1,16–6,37

Outcome (death)

4 (4%)

3 (2%)

3,61

0,65–19,91