• chronic lung disease;
  • prematurity;
  • Ureaplasma urealyticum;
  • very low-birthweight infants

Objective: The aim of the present prospective cohort study was to evaluate the relationship between lower respiratory tract colonization with Ureaplasma urealyticum and development of chronic lung disease (CLD) in a high-risk neonatal population.

Methods: Prospective cohort study of preterm infants with a birthweight < 1500 g needing mechanical ventilation within 24 h of birth in a tertiary care neonatal unit. Endotracheal aspirates from these infants were cultured within 24 h for U. urealyticum and the rate of colonization was determined. The primary outcome measure was the incidence of CLD at 28 days of life.

Results: Of the 41 infants studied, 10 (24%) infants were colonized with U. urealyticum. The colonization rate was higher in babies < 1000 g compared with babies weighing 1000–1500 g (P = 0.04). There was no significant difference between the colonized and non-colonized groups with regard to the antenatal use of steroids, maternal prolonged rupture of membranes, gestational age, birthweight, sex, respiratory distress syndrome, use of surfactant, patent ductus arteriosus and gastrooesophageal reflux. Of the 37 survivors, 20 (54%) developed CLD; eight infants (88.5%) in the colonized group developed CLD compared with 12 infants (42.8%) in the non-colonized group (P = 0.01).

Conclusions: Neonates colonized with U. urealyticum were twice as likely to have CLD than non-colonized babies (relative risk 2.01; 95% confidence interval 1.27–3.37). These data suggest a significant association between colonization with U. urealyticum and CLD in infants weighing < 1500 g.