Table 1 Risk factors for colonization with Gram-negative bacteria in 235 transfer patients

sex (female)

20 (47.6 %)

77 (39.9 %)

1.4 (0.7-2.7)

0.36

Age

53 (±16.6)

55.4 (±19.6)

0.99 (0.98-1.01)

0.46

Swiss residents

37 (88.1 %)

178 (92.2 %)

0.6 (0.2-1.8)

0.37

Inpatient hospitalization in Bern

36 (85.7 %)

170 (88.1 %)

0.8 (0.3-2.1)

0.67

 • Intensive care unit

10 (23.8 %)

29 (15.0 %)

1.8 (0.8-3.98)

0.17

 • surgical wards

13 (31.0 %)

74 (38.3 %)

0.7 (0.4-1.5)

0.37

 • medical wards

13 (31.0 %)

67 (34.7 %)

0.8 (0.4-1.7)

0.64

Number of swabs/samples

4 (3-10)

3 (3-9)

1.4 (1.1-1.7)

0.03

Risk factors on admission:

Medical device

13 (31.0 %)

41 (21.2 %)

1.7 (0.8-3.5)

0.18

 • urinary catheter

10 (23.8 %)

36 (18.7 %)

1.4 (6.1-3.02)

0.45

 • intubation/ tracheostomy

6 (14.3 %)

11 (5.7 %)

2.8 (0.96-7.9)

0.09

 • wound drain

3 (7.1 %)

4 (2.1 %)

3.6 (0.8-16.9)

0.11

Skin lesion

17 (40.5 %)

34 (17.6 %)

3.2 (1.5-6.5)

0.001

1.9 (0.7-4.7)

0.18

Number of risk factors

0 (0-3)

0 (0-3)

2.02 (1.4-2.97)

0.0006

Antibiotic treatment

17 (40.5 %)

43 (22.3 %)

2.4 (1.2-4.8)

0.014

1.3 (0.5-3.3)

0.54

 • number of antibiotics

0 (0-3)

0 (0-3)

1.7 (1.2-2.6)

0.008

 • antibiotic days up to admission

8.5 (±11.7)

5.8 (±6.4)

1.03 (0.96-1.1)

0.31

Active infection

15 (37.5 %)

29 (15.9 %)

3.2 (1.5-6.8)

0.002

2.7 (1.07-6.6)

0.035

Surgical procedure abroad

15 35.7 %

33 17.1 %

2.7 (1.3-5.6)

0.007

1.5 (0.6-3.8)

0.39

Direct transfer

24 (57.1 %)

123 (63.7 %)

0.8 (0.4-1.5)

0.42

Indirect transfer, days between last exposure abroad until admission

22 (±24.6)

21 (±28.9)

1.0 (0.98-1.02)

0.92

Individual transportation

13 (31.0 %)

55 (28.5 %)

1.1 (0.5-2.3)

0.75

Europe

18 (42.9 %)

142 (73.6 %)

0.3 (0.1-0.5)

<0.001

 • Switzerland

2 (4.8 %)

13 (6.7 %)

0.7 (0.2-3.2)

1

 • Spain

4 (9.5 %)

25 (13.0 %)

0.7 (0.2-2.2)

0.54

 • Italy

2 (4.8 %)

27 (14.0 %)

0.3 (0.1-1.4)

0.099

 • France

4 (9.5 %)

15 (7.8 %)

1.2 (0.4-3.97)

0.754

Outside Europe

24 (57.1 %)

51 (26.4 %)

3.7 (1.9-7.4)

<0.001

3.2 (1.5-6.8)

0.002

 • Asia

14 (33.3 %)

25 (13.0 %)

3.4 (1.6-7.2)

0.001

o south/southeast Asia

9 (21.4 %)

11 (5.7 %)

4.5 (1.7-11.7)

0.003

 • Africa

6 (14.3 %)

11 (5.7 %)

2.8 (0.96-7.9)

0.09

 • America (North, South)

3 (7.1 %)

13 (6.7 %)

1.1 (0.3-3.9)

1