Study On Pathogen And Infection Indexes Of Lower Respiratory Tract Infection In Children

Objective:To investigate the etiological characteristics and diagnostic value of IgM antibody(igm-ab)from Lower respiratory tract infection in children.The significance of the detection and analysis of infection indexes(leukocyte,c-reactive protein,procalcitonin)for the application of antibiotics.Methods:Blood samples were collected from 1980 children diagnosed as lower respiratory tract infection(LRTI)in pediatric department of the Second Affiliated Hospital of Nanchang University from November 2017 to November 2019(1029boys and 951 girls,aged from 1 month to 14 years old).By indirect immunofluorescence method that IgM antibody detection of nine respiratory pathogens(including eosinophilic lung legionella pneumonia(LP),mycoplasma pneumonia(MP)and chlamydia(CP),Q fever rickettsia(QFR),adenovirus(ADV)and respiratory syncytial virus(RSV),influenza a virus(INFA),hepatitis b virus(INFB)and parainfluenza 1,2,3(PIVs).Among them,199 patients with simple parainfluenza virus infection(PIVs)IgM antibody were selected to detect positive.Meanwhile,indirect immunofluorescence method was used to detect procalcitonin(PCT),immunofluorescence dry quantitative method was used to detect C-reactive protein,and blood routine test results were used to determine the situation of bacterial infection in children.The data were statistically analyzed by SPSS 23.0statistical software package,and the count data were expressed as percentage(%).Chi-square test was performed on the data,and the difference was statistically significant when P<0.05.In analysis of variance,mean±standard deviation((?)±s)when P<0.05 was used,the difference was statistically significant.Results:(1)A total of 482(24.34%)of the 1980 children were positive for IgM antibody of respiratory pathogens.The positive rate of single infection and compound infection was 20.91%and 3.43%,respectively.The positive rate was highest for parainfluenza virus(PIVs),followed by QFR,Chlamydia pneumoniae(CP)and Mycoplasma pneumoniae(MP).(2)The positive rates of children of different genders were analyzed.There was no significant difference in IgM between male and female children(?~2=2.641,P=0.104).(3)The incidence of respiratory pathogens among different age groups was statistically significant(?~2=16.19,P=0.001).The positive rate of young children(<6years)was significantly higher than that of older children(>6 years)(?~2=12.185,P=0.000).(4)The positive rates of children in different seasons were analyzed,and the incidence was high in spring(29.77%).The number of respiratory pathogen infections in spring was higher than that in autumn(?~2=4.308,P=0.038),but there was no significant difference between summer and winter(?~2=0.002,P=0.996).(5)The positive rate of inflammatory indicators was 31.66%in 199 children with positive parainfluenza virus.The positive PCT detection rate was30.15%.Combined testing increases the detection rate of bacterial infections.Three inflammatory indicators to determine whether bacterial infection should be combined with other pathogenic tests,such as sputum culture,blood culture,etc.Conclusion:(1)From 2017 to 2019,there were significant differences in age groups among hospitalized children with lower respiratory tract infection and positive respiratory tract pathogens,most of which were less than 1 year old.The positive rate of the early school age group was significantly higher than that of the late school age group.There was no significant difference between male and female children.(2)This study showed that parainfluenza virus(PIVs)had the highest positive rate of respiratory pathogen IgM antibody,followed by QFR and Chlamydia pneumoniae(CP).(3)Respiratory tract infection is seasonal.This study shows that the incidence of respiratory tract pathogen infection in children is high in spring,suggesting that according to the epidemiological characteristics of each region,effective measures such as vaccination,reduced travel and indoor ventilation can be taken for susceptible people in the epidemic season.(4)Combined PCT,CRP and WBC counts in children with respiratory tract pathogen infection have certain guiding significance for the judgment of virus or bacteria.