Study On Mechanism Of Comparative Analysis Of MP Nucleic Acid Detection Positive Rate Of Pharyngeal Swab And Bronchoalveolar Lavage Fluid In Children With Mycoplasma Pneumonia

Objective:The purpose of this paper is to analyze the nucleic acid detection results of pharynx and bronchoalveolar lavage fluid(BALF)in patients with mycoplasma pneumoniae pneumonia,and to compare the difference in positive rate and sensitivity between them,so as to explore the value of fluorescence quantitative PCR detection in clinical diagnosis,so as to provide guidance for clinical work in pediatrics.Methods:In this study,509 children with mycoplasma pneumoniae pneumonia were selected from Changchun Children’s Hospital from January 2019 to January 2020.The subjects were selected according to the inclusion criteria and exclusion criteria,and the general data investigation method was used to collect data.Among them,216 cases were tested by fluorescent quantitative PCR of mycoplasma pneumoniae in two different parts of pharynx swab and bronchoalveolar lavage fluid in the same period.The relevant clinical data were recorded.Results:(1)There were 23 cases in spring,45 cases in winter,56 cases in summer and 92 cases in autumn,and there was no significant difference in the detection rate of mycoplasma pneumoniae PCR between different seasons.(2)The age and sex distribution of the subjects were as follows: 29 cases of 0-1 years old,53 cases of 1-3 years old,50 cases of 3-6 years old and 84 cases of 6-14 years old.There was no significant difference in the detection rate of MP samples of different ages between the two parts,male 112 cases and female 104 cases.There was no significant difference in the detection rate of MP samples between the two parts between different sexes.(3)Among the 216 subjects,13 cases were positive for PCR and negative for PCR in bronchoalveolar lavage fluid,99 cases were positive for PCR and negative for PCR in bronchoalveolar lavage fluid,68 cases were positive in both sites,and 36 cases were negative.(4)Among the 216 subjects,81 cases were positive for pharynx swab PCR,with a detection rate of 37.5%,and 167 cases were positive for MP fluorescence quantitative PCR in bronchoalveolar lavage fluid(BALF),with a detection rate of 77.3%.The difference in the detection rate of mycoplasma pneumoniae PCR between samples from two different parts was statistically significant.(5)The positive rate of MP in bronchoalveolar lavage fluid of children with severe mycoplasma pneumoniae pneumonia was higher than that of pharyngeal swabs.There was a significant difference in the positive rate of mycoplasma pneumoniae PCR between severe and mild children with mycoplasma pneumoniae pneumonia.(6)The difference of MP-DNA copy number of samples from two different sites in the same period was statistically significant,and the positive rates of mycoplasma pneumoniae in children with mycoplasma pneumoniae pneumonia and refractory mycoplasma pneumoniae pneumonia were detected by fluorescence quantitative PCR,and the difference was statistically significant.Conclusion:(1)There was no significant difference in the positive rate of Mycoplasma pneumoniae among different seasons,age and sex groups.(2)The positive rate and sensitivity of fluorescence quantitative PCR of mycoplasma pneumoniae in bronchoalveolar lavage fluid were significantly higher than those in pharyngeal swabs,and it was more valuable in clinical diagnosis.(3)The number of DNA copies of Mycoplasma pneumoniae detected by pharynx swabs did not increase with the increase of bronchoalveolar lavage fluid samples.(4)The detection of Mycoplasma pneumoniae nucleic acid in bronchoalveolar fluid(BALF)is more suitable for children with severe mycoplasma pneumoniae pneumonia.