Objective To analyze the clinical characteristics and risk factors of ureaplasma urealyticum (UU) infection in preterm infants. Methods A total of 462 preterm infants admitted to the Neonatal Intensive Care Unit (NICU) of Nanyang Central Hospital from January 2023 to January 2025 were enrolled. According to the test results of UU testing of lower respiratory tract secretions was performed within 48 hours after birth, and these infants were divided into the UU positive group of 130 cases and the UU negative group of 332 cases. The general data, laboratory examination indicators, and treatment conditions of the two groups of preterm infants, as well as the pregnancy and perinatal related indicators of their mothers were compared. Multivariate Logistic regression was used to analyze the influencing factors of UU infection, and a combined diagnostic model was established and the receiver operating characteristic (ROC) curve was drawn. Results Compared with the UU-negative group, the UU-positive group of preterm infants had lower gestational age, birth weight, 1-minute Apgar score, 5-minute Apgar score, and platelet (PLT), and higher proportions of infants with acute respiratory distress syndrome, bronchopulmonary dysplasia (BPD), sepsis and intracranial hemorrhage, as well as increased levels of white blood cell (WBC), neutrophil (NEUT), and C-reactive protein (CRP), and longer durations of antibiotic use, mechanical ventilation, and oxygen therapy (P<0.05). Compared with the UU-negative group, the mothers of the UU-positive group had a higher proportion of UU infection history, concurrent chorioamnionitis, premature rupture of membranes, antepartum fever, vaginal delivery, and amniotic fluid grade Ⅲ contamination during pregnancy, and longer duration of labor (P<0.05). There were no statistically significant differences in maternal age, parity, gravidity, conception method, concurrent gestational hypertension and gestational diabetes between the two groups. Multivariate Logistic regression analysis showed that concurrent sepsis, concurrent intracranial hemorrhage, maternal UU infection history, concurrent chorioamnionitis during pregnancy and vaginal delivery were independent risk factors for UU positivity in neonates, while higher birth weight, 5-minute Apgar score and longer duration of antibiotic use were independent protective factors. The area under the receiver operating characteristic (ROC) curve of the combined diagnostic model was 0.949 (95%CI: 0.925-0.968). Conclusion Screening for risk factors of UU positivity in the respiratory tract of preterm infants can enable early identification and reduce the risk of UU infection in preterm infants in the NICU.
