Table 1. Characteristics of the cases and controls matched for weight at birth and age during exposure time.

	Cases	Controls	Level of significance (p-value)#
Weight at birth (median and range)	1165 g (606–3800 g)	1256 g‡ (625–3740 g)	0.91
MRSA infection†	22% (5/23)	n/a
Duration until MRSA positive (median and range)	8 days* (2–91 days)	n/a
Male gender	52% (12/23)	41% (15/37)	0.38
Birth by caesarean section	83% (19/23)	81% (29/36)	0.84
Multiples	52% (12/23)	35% (13/37)	0.15
Gestational age (median and range)	29 weeks (23–42)	32 weeks‡ (24–41)	0.43
Born on-site	91% (21/23)	97% (32/33)	0.35
Length of stay (median and range)	47 days (6–103)	38 days‡ (7–116)	0.61

^*from birth or last negative swab to first positive.

^#Kruskal Wallis, Chi2.

^†as opposed to colonisation.

^‡In pairs with two controls, the average value of the controls was used for the calculation.