Identification and quantification of ureaplasmas colonizing the respiratory tract and assessment of their role in the development of chronic lung disease in preterm infants

Background. The role of Ureaplasma urealyticum in the development of chroni c lung disease (CLD) in preterm infants continues to be disputed. Recently U. urealyticum has been found to consist of two species, U. urealyticum and Ureaplasma parvum, a finding that has not been considered in previous stud ies of CLD. This study examined the possible relationships between developm ent of CLD and respiratory colonization by these newly redefined species, t heir concentrations in lower respiratory secretions and the effect of pulmo nary surfactant treatment on these relationships in preterm infants with bi rth weights < 1500 g. Methods. Endotracheal aspirates (ETA) were collected from intubated infants when airway suctioning was medically required. ETA were stored at -80 degr eesC until quantitative cultures for ureaplasmas and Mycoplasma hominis wer e performed. Culture results were correlated with development of CLD. Results. Of 475 infants (birth weights < 1500 g) admitted during the 2-year study period, 272 were excluded because they were not intubated or were ex tubated before ETA could be obtained. An additional 28 infants died, were d ischarged or were transferred before they could be assessed for CLD. From t he remaining 175 infants ureaplasmas were isolated from 66 (38%). No statis tically significant associations were identified between development of CLD and the Ureaplasma species isolated, or concentration of ureaplasmas in lo wer respiratory secretions. These findings were not altered by treatment wi th pulmonary surfactant (Survanta). Conclusion. Lower respiratory colonization by ureaplasmas does not appear t o be a contributory cause of CLD in preterm infants.