The Etiological Studies Of Alveolar Lavage Fluid In Children With Lower Respiratory Tract Infection

With the change of living environment and the aggravation of air pollution,the morbidity of children’s respiratory tract infection increases further and becomes the main cause of children’s death.In China,about 60% of children died in hospital due to lower respiratory tract infection,and about 1/3 died of pneumonia,which has a serious impact on children’s physical and mental health and the country’s medical health.There are many kinds of pathogens causing lower respiratory tract infection.The pathogens of lower respiratory tract infection are different in different countries and regions.In developing countries,the main pathogens of lower respiratory tract infection are bacteria,while in developed countries,viruses are the main pathogens of lower respiratory tract infection.It has been reported that the detection rate of bacteria in children’s lower respiratory tract infection is as high as 82.5%,so it is more important to identify the pathogen of lower respiratory tract infection in the early stage.But because pathogens often lack specificity in children,laboratory tests play an important role in identifying pathogens.In clinical practice,common methods of detecting pathogens are traditional culture method and immune detection method,but due to long time consuming,low sensitivity,process is tedious,pathogen detection positive rate is low,and most of the children has a history of use of antibiotics before sampling,the positive rate of detecting pathogens are lower,unable to meet the requirements of rapid diagnosis.ObjectiveDue to the particularity of children’s anatomy,physiology and immunity,children’s lower respiratory tract infection has become a common and frequent disease,which seriously threatens children’s health.In addition,due to the lack of effective and rapid laboratory examination methods for identifying pathogens,the empirical application of broad-spectrum antibiotics is more common,leading to drug resistance of most bacteria.In this study,the pathogen characteristics of children with lower respiratory tract infection were studied by multiple real-time PCR detection methods,so as to provide a basis for clinicians to reasonably use antibiotics in the diagnosis and treatment of children with lower respiratory tract infection.MethodsFrom January 2017 to June 2018,108 children hospitalized in the respiratory department of the third affiliated hospital of zhengzhou university due to lower respiratory tract infection and treated with fiberoptic bronchoscopy were selected as subjects.Collection of 108 cases obtained via fiberoptic bronchoscopy bronchoalveolar lavage fluid(BALF),sterile tubes,under the condition of 4 ℃ ~ 8 ℃ immediately sent to lab for testing,if not timely inspection,-70 ℃ in the refrigerator freezer.The principle of fluorescence probe dissolution curve technique was used to detect 18 pathogens in BALF simultaneously with a single tube(including rickettsia,streptococcus pneumoniae,haemophilus influenzae,catarrh mora bacteria,acinetobacter baumannii,klebsiella pneumoniae,eosinophilic lung legionella bacteria,mycoplasma pneumoniae,smoke aspergillus,pneumonia chlamydia,candida albicans,whooping cough bacili,escherichia coli,staphylococcus aureus,cryptococcus,verdigris false unit cell bacillus,streptococcus pyogenes,staphylococcus epidermis).The data was processed using the Microsoft Excel 2007 software package.SPSS 21.0 statistical software was used for data analysis.Counting data were expressed as a percentage(%),and comparison between groups was conducted by chi-square test or Fisher’s exact test.P<0.05 was considered statistically significant.Results1.Total detection of pathogensAmong the 108 samples,There were 85 specimens detected by multiple real-time fluorescent PCR assays,and the positive rate was 78.7%.A total of 52 cases of single pathogen and 33 cases of multiple pathogen infection were detected.Among them,38 cases of mycoplasma pneumoniae were detected,accounting for 35.2% of the total cases,among which 23 cases were children over 36 months old,accounting for 61% of the total positive cases of mycoplasma pneumoniae.Streptococcus pneumoniae was detected in 29 samples,the same number of cases as haemophilus influenzae,accounting for 26.9% of the total cases.Moraxella catarrh and staphylococcus aureus were detected in 12 cases each,accounting for 11.1% of the total cases.The detection of acinetobacter baumannii,candida albicans and klebsiella pneumoniae were the same,3 cases were detected,accounting for 2.8% of the total cases.Among the multiple pathogen infections,there were 23 cases of double pathogen infection and 10 cases of triple or above pathogen infection.2.Pathogenicity physical examination of children in different age groupsIn this study,14 cases(82%)of children aged 29 days to less than 12 months were detected by physical examination,among which the detection rate of streptococcus pneumoniae was higher than that of other age groups,while the detection rate of mycoplasma pneumoniae was lower than that of other age groups.Among the 12~ 36 months old children,37 cases(74%)were detected by physical examination,and the detection rates of haemophilus influenzae,morazella catarrh and staphylococcus aureus were higher than other age groups.Among the children aged 36~ 72 months,21 cases(84%)were detected by physical examination,among which the detection rate of mycoplasma pneumoniae was higher than that of children aged 12~ 36 months and 29 days to 12 months.Among the 72 months to 9 years old group,13 cases(81%)of pathogens were detected,and the detection rate of mycoplasma pneumoniae was second only to that of children aged 36 months to <72 months.3.Physical examination of different diseasesIn 31 cases of bronchopneumonia specimens,a total of 21 cases detected pathogens,positive rate was 68%.Among them,14 cases of a single pathogen infection,mixed pathogen infection detected in 7 cases,in the group of children,h.influenzae detection rate is highest,accounted for 29% of the group total number of cases,followed by mycoplasma pneumoniae,accounted for 26% of the group total number of cases,streptococcus pneumoniae,accounted for 16% of the group total number of cases,staphylococcus aureus and card he mora bacteria,accounted for 10% of the group total number of cases,candida albicans and acinetobacter baumannii,accounted for 3% of the group total number of cases.In 34 cases of lobar pneumonia in children with pneumonia,a total of 30 cases detected pathogens,the positive rate was 88%,among them,there are 20 cases for a single pathogen infection,10 cases of mixed infection pathogens.In the group,in children with mycoplasma pneumoniae detection rate is highest,accounted for 65% of the group total number of cases,followed by streptococcus pneumoniae,accounted for 24% of the group total number of cases,h.influenzae,accounted for 15% of the group’s total number of cases,Moraxella catarrhalis accounted for 12%,staphylococcus aureus accounted for 9% of the total of the group,acinetobacter baumannii and with klebsiella pneumoniae,accounted for 3% of the group total number of cases.Among the 22 cases of bronchial foreign bodies combined with bronchopneumonia,a total of 18 cases were detected with pathogens,with a positive rate of 82%.Among them,8 cases were detected with single pathogen infection,10 cases of multiple pathogen infection were detected。In the group of children,streptococcus pneumoniae detected rate is the highest,accounted for 45% of the group total number of cases,followed by h.influenzae,accounted for 32% of the group total number of cases,mycoplasma pneumoniae and Moraxella catarrhalis,accounted for 18% of the group total number of cases,staphylococcus aureus,14% of the total of the group,acinetobacter baumannii,accounted for 5% of the group total number of cases.Among the 4 cases of interstitial pneumonia,pathogens were detected in 3 cases.Pathogens were detected in 4 of 6 bacterial bronchitis specimens.Pathogens were detected in 3 of 4 cases of interstitial pneumonia.Pathogens were detected in 4 of 6 bacterial bronchitis specimens.Pathogens were detected in 2 of the 4 cases of whooping cough syndrome.Conclusion1.Mycoplasma pneumoniae,streptococcus pneumoniae and haemophilus influenzae were the main pathogens in children undergoing bronchoscopy in our hospital due to lower respiratory tract infection.2.The top three pathogen detection rates of children with bronchopneumonia were haemophilus influenzae,mycoplasma pneumoniae and streptococcus pneumoniae.The detection rate of mycoplasma pneumoniae was the highest in the lobar pneumonia group,followed by streptococcus pneumoniae and haemophilus influenzae.3.Mycoplasma pneumoniae and streptococcus pneumoniae are the main pathogens of most mixed infections.