| With the development of perinatal medicine and the continuous progress in neonatal intensive care,the survival rate of rescue in premature infants is increasing.However,no significant improvements in the incidence of serious complications and sequelae in these infants.Studies have shown that the incidence of bronchopulmonary dysplasia(BPD)in premature infants shows an annual rising trend.At present,BPD is still one of the most intractable problems in neonatal intensive care unit,and its mortality and prognosis are still not optimistic.Survivors had high odds of readmission to hospital,mainly due to recurrent lower respiratory tract infection,so it is far more important to prevent the occurrence of BPD than to treat it after it occurs.It has been confirmed that BPD is caused by many factors,among which intrauterine infection and inflammation are important factors in the occurrence of BPD.Ureaplasma urealyticum(UU)is an opportunistic pathogen mainly colonized in the genitourinary tract of women during the reproductive age.Under specific circumstances,UU can cause pregnancy-related diseases such as chorioamnionitis,infertility,spontaneous abortion and preterm delivery.Studies on the infection of UU were reported abroad as early as the 1980s.Gradually,people realized that UU is one of the critical pathogens of neonatal intrauterine infection and can cause a high rate of vertical mother-to-infant transmission.Moreover,UU can promote the expression of fetal pro-inflammatory factors and evade the host immune system,resulting in recurrent and persistent chronic infection.Although a large number of studies have shown that the infection of UU is closely related to the occurrence of BPD,it is undeniable that controversy still exists.The purpose of this study is to explore the relationship between the infection of UU and the risk of BPD and to provide basis for diagnosis and treatment of BPD through retrospective analysis which can bring early prevention and intervention to improve the long-term outcome of premature infants.Objective1.To explore the relationship between respiratory tract infection of UU and BPD in premature infants.2.To explore the relationship between DNA copy number of Ureaplasma Urealyticum and BPD by PCR detection.MethodsA total of 288 premature infants who were born in the Third Affiliated Hospital of Zhengzhou University from January 1,2019 to August 31,2020 and admitted to the NICU within 24 hours with gestational age<32 weeks and hospital stay>28 days were selected as the study subjects.According to the diagnostic criteria of neonatal respiratory tract UU infection,the patients were divided into two groups:UU infection group and non-UU infection group.Finally,217 patients were included in the study,with 62 cases in UU infection group and 155 cases in non-UU infection group.The maternal pregnancy,basic conditions,treatment process and clinical outcome of the two groups were analyzed.Through the ROC curve of the relationship between UU-DNA copy number and BPD,the best tangent point was found.According to this dividing line,the UU infection group was divided into UU-DNA high copy group(n=28)and UU-DNA low copy group(n=34).The respiratory treatment and outcome of the two groups of premature infants were further analyzed.SPSS Statistics 26.0 software was used for statistical analysis.The measurement data in accordance with normal distribution were expressed as x±s,and the t-test was used for inter-group comparison;the measurement data of skewed distribution were expressed as median(quartile spacing),and the non-parametric rank sum test was used for inter-group comparison;the counting data were expressed by examples and percentages,and the inter-group comparisons were performed by χ2 test.Binary Logistic regression analysis was used to analyze the relationship between UU infection and moderate and severe BPD.Differences with P<0.05 were considered significant.Results1.The gestational age of premature infants in UU infection group was significantly lower than that in non-infection group.The rates of vaginal delivery and premature rupture of membranes in UU infection group were higher than those in non-infection group.The differences were statistically significant.There was no significant difference in gender composition,weight distribution,postnatal Apgar score,prenatal use of corticosteroids and high risk factors during pregnancy between the two groups.2.There was no significant difference in the incidence of BPD between the two groups,but the incidence of moderate and severe BPD in the UU infection group was higher than that in the non-infection group(P=0.003).The probability of using PS more than twice in UU infection group was significantly lower than that in non-infection group(P=0.044).There was no significant difference in the proportion of invasive mechanical ventilation between the two groups.The proportion of invasive mechanical ventilation>14 days in UU infection group was higher than that in non-infection group(P=0.014).The time of oxygen therapy was prolonged(P=0.039),and the incidence of postnatal infectious pneumonia was increased(P=0.040),the difference was statistically significant.Binary logistic regression analysis showed that UU infection was related to the occurrence of moderate and severe BPD.UU infection,vaginal delivery,small gestational age,oxygen concentration>40%and male may be independent risk factors for moderate and severe BPD.3.In 62 children with UU infection,the range of UU-DNA copy number was 1.3×10～3.1×108/mL,the area under ROC curve in the ROC curve of the relationship between UU-DNA copy number and BPD was 0.678,when the UU-DNA copy number was 1.65×106/mL,the sensitivity of predicting the occurrence of BPD was 57.8%and the specificity was 88.2%,which was the best tangent value.4.The incidence of BPD and moderate and severe BPD in preterm infants with UU infection was significantly increased(P=0.001,0.013),and the ventilation time and oxygen therapy time of invasive mechanical ventilation were prolonged(both P<0.05).Conclusion1.UU infection may be associated with spontaneous preterm birth and premature rupture of membranes.2.UU infection is significantly correlated with the occurrence of moderate and severe BPD,and may increase the oxygen demand and the incidence of infectious pneumonia in premature infants during treatment.3.The risk of BPD in premature infants with high copy number of UU-DNA is significantly increased,and the severity of BPD is increased.The duration of ventilation and oxygen demand in this group is significantly longer as well.UU-DNA detection is helpful for early detection of infection and early intervention which can reduce the severity of BPD and improve the prognosis. |
