A primate model of Ureaplasma urealyticum infection in the premature infant with hyaline membrane disease.

Cultures positive for Ureaplasma urealyticum in babies weighing < 1000 g have been associated with both chronic lung disease (CLD) and death, but no definite causality has been established. To further investigate the role of the organism in CLD, we colonized premature baboons with U. urealyticum and compared resulting pathology with that in uninoculated control animals. Using an established model of prematurity, the 140-day-gestation baboon, three animals were colonized with U. urealyticum via endotracheal tube. All had hyaline membrane disease, indistinguishable from disease in human infants, and U. urealyticum infection. Samples obtained from nasopharynx, trachea, pleural fluid, and, at necropsy, lung tissue produced positive cultures. Culture of blood from one animal yielded U. urealyticum. On pathologic examination, after 6 days of ventilation, all three of the infected animals had the specific pathologic finding of bronchiolitis with epithelial ulceration not seen in four uninfected control animals. Thus, U. urealyticum is capable of causing a pathologically recognizable pulmonary lesion in premature primates with hyaline membrane disease.