Background: Recent studies of chronic lung disease (CLD) of newborns emphasize the contribution of antenatal infection. However, the association of Ureaplasma urealyticum infection and CLD has been controversial. The purpose of the present paper was to determine whether U. urealyticum is associated with chorioamnionitis (CAM) and a certain type of CLD.
Methods: One hundred and five infants <32 weeks of gestation who were admitted to the neonatal intensive care unit at Jichi Medical School Hospital, who underwent both histological and microbiological examinations and who survived to discharge were included. CAM was determined by histological examination. Placenta, gastric and tracheal aspirates, and nasopharyngeal swabs were cultured for Mycoplasma and other microorganisms. CLD was defined as oxygen needed at 28 days of age with symptoms of persistent respiratory distress and hazy or emphysematous and fibrous appearance upon X-ray. CLD was further divided into two subtypes according to the presence of antenatal infection.
Results: CAM was associated with premature rupture of membrane (odds ratio [OR], 10.19; 95% confidence interval [CI]: 3.10-33.56), placental colonization of U. urealyticum (OR 6.73, 95%CI: 1.89-23.91), neonatal colonization of other microorganisms (OR 7.33, 95%CI: 1.22-44.13) and level of IgM (OR 1.06, 95%CI: 1.01-1.11). Comparisons between CLD and non-CLD patients showed that gestational age (OR 0.43, 95%CI: 0.30-0.61) and white blood cell count (WBC) at birth (OR 1.06, 95%CI: 1.01-1.11) were risk factors for CLD, while gestational age (OR 0.38, 95%CI: 0.23-0.64), neonatal colonization of U. urealyticum (OR 5.98, 95%CI: 1.17-30.6) and WBC (OR 1.08, 95%CI: 1.01-1.15) were independent risk factors for infection-related CLD compared with non-CLD. Within CLD, infection-related CLD was associated with neonatal colonization of U. urealyticum (OR 43.7, 95%CI: 2.84-673.8) and WBC (OR 1.27, 95%CI: 1.07-1.50).
Conclusions: Placental colonization of U. urealyticum was significantly related to CAM; and neonatal colonization of U. urealyticum and leukocytosis at birth were risk factors for infection-related CLD.