Decreasing incidence of neonatal nosocomial bloodstream infections in a neonatal intensive care unit: antenatal corticosteroid treatment an innocent bystander?

Unlabelled: We studied the effect of the use of antenatal steroid treatment on the incidence of nosocomial bloodstream infections (NBSI). All episodes of culture proven NBSI occurring after 96 h of hospitalisation were identified retrospectively during a 10-year period (1991-2001). Throughout the study period, the use of antenatal steroids, demographic characteristics and morbidity of the patients were recorded prospectively. Since 1996 more efforts were made to use antenatal steroids to decrease neonatal morbidity and mortality. The incidence rates of NBSI were compared between period 1 (1991-1995) and period 2 (1996-2001). The overall incidence rate of NBSI dropped significantly from 7.4% (6.1%-8.9%) in period 1 to 5.0% (4.0%-6.2%) in period 2 and was most pronounced in the birth weight category 1000 g-1500 g (11.7%, 7.9%-15.0% to 6.9%, 4.3%-10.5%) and 1500 g-2500 g (3.6%, 2.2%-5.6% to 1.4%, 0.6%-2.8%). Antenatal use of steroids increased overall from 19% in 1991 to 51% in 2001 ( P<0.001). Since 1996 there was a decreasing number of ventilation days ( P=0.011) and decreasing incidence of patent ductus arteriosus ( P=0.001), while the incidence of neonatal surgery, chronic lung disease and duration of hospitalisation remained constant over time.

Conclusion: increased use of antenatal steroids is associated with a decreasing incidence rate of nosocomial bloodstream infections in neonates with birth weights between 1000 g and 2500 g, probably by decreasing the incidence of patent ductus arteriosus and/or due to improved respiratory outcome. This finding needs to be confirmed by randomised control trials or by a large prospective cohort study in similar population groups.