Table 1

Univariate anaysis of risk factors associated with Serratia marcescens infection or colonzation
Characteristic Case patients (n= 105) Control patients (n= 206) OR CI95
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

Note. Time-dependent risk factors have been evaluated until the first positive culture for Serratia marcescens.

OR odds ratio, CI95 95% confidence interval.

*statistical significance (p< 0.05).

Adamson et al.

Adamson et al. BMC Infectious Diseases 2012 12:281   doi:10.1186/1471-2334-12-281

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