Clinical Study Of The Co-infections In Children Hospitalized With Community-acquired Pneumonia

Objective:To explore the etiological and clinical characteristics,risk factors of the co-infections in children hospitalized with community-acquired pneumonia(CAP).Methods:We enrolled the children diagnosed with CAP hospitalized in the Department of respiration of Children’s Hospital Affiliated to Soochow University from January 2015 to December 2016.Multipathogen detection was performed in our study,including bacteria culture,direct immunofluorescence used to detect common seven respiratory viruses including respiratory syncytial virus(RSV),influenza virus A and B(FluA,FluB),parainfluenza virus type 1,2,3(PIV 1,PIV 2,PIV 3),adenovirus(ADV),PCR of nasopharyngeal aspirates for the detection of human metapneumovirus(hMPV),human Bocavirus virus(hBoV),human respiratory rhinovirus(hRV),Mycoplasma pneumoniae(MP)and Chlamydia pneumoniae(CP).At the same time,blood,C reactive protein(CRP),liver function,humoral immunity,cellular immunity detection and the serum antibody of MP were examined.A multipathologic detection was performed on the pulmonary alveolar lavage in children with bronchoscopy,and the pleural effusion was detected in patients undergoing thoracic puncture during hospitalization.Collect and collate the clinical data of the children enrolled in our study,compare the clinical features,pulmonary symptoms,basic diseases,laboratory examination,chest imaging and so on among the different number pathogens co-infection and different pathogens combinations,and between the Single-pathogen infections and multi-pathogen co-infections.Then use the logistic regression analysis to explore the risk factors of co-infections.Results:Part I.The etiological and clinical characteristics of the co-infections in children hospitalized with CAP.1.2659 children with CAP were rolled in our study.At least one respiratory pathogen was detected in 2043(76.8%)of the children,single pathogen was identified in 1155(43.4%)children,co-infections was 888(33.4%).Among them,two pathogens co-detected were 676 children(76.1%),three pathogens were identified in 190 children(21.4%),more than three pathogens were 22 children(2.5%).Two pathogens co-infection occupied the largest proportion,which was statistically significant(P<0.05).2.Among children with co-infection,the rate detection of boys was 33.1%while girls was 33.8%,there were no statistically significance between the two groups(~2=0.068,P>0.05).3.The proportions of co-infection among each age group(<6 months,6 months~1year old,1~3 years old,3~5 years old,≥5 years old)were 34.9%,45.8%,31.9%,45.8%,20.1%.The highest proportion of co-infection was in the age group of 6 months~1year old while the lowest proportion was in the age group of≥5 years old,which has statistical significance(~2=53.341,P<0.05).4.During 2015~2016 years,the co-infection rates in spring,summer,autumn and winter were 32.9%,29.8%,36.5%,29.8%.The detection rate of co-infection was highest in the fall and winter,summer lowest,the difference was statistically significant(~2=8.848,P<0.05).5.The co-infection had the combinations of virus+bacteria(13.6%),virus+virus(3.4%),bacteria+bacteria(4.8%),virus++bacteria+MP(3.6%),MP+virus(11.2%),MP+bacteria(11.6%),MP+CP(0.3%),and so on.Among them,the combination of viral-bacterial co-infection was the most common,which was statistically significant(P<0.05).HRV and RSV were the most commonly detected virus of co-infection while the Streptococcus pneumoniae,Haemophilus influenzae were the most commonly bacteria.HRV mixed with S.pneumoniae was the most identified combination of co-infection.6.Of all age groups,the co-infection of<6 month age group were mainly composed with virus+MP(31.8%),virus+bacterial(31.8%),hRV+MP were the most common pathogen in the combination of virus+MP and hRV+Haemophilus influenzae were the most common pathogen in the combination of virus+bacterial.~1 year old group,virus and bacterial co-infection(57.6%)were the most common combination,hRV+Streptococcus pneumoniae were the common detection pathogen;MP+bacterial co-detection(39.8%)were the major combination respectively in~3 years old group,5 years old group and≥5years old age group,MP+Streptococcus pneumoniae were the common combination of the co-infection.7.Among children hospitalized with CAP,even though the different number of co-infection pathogens,different pathogen combinations,clinical characteristics such as cough,wheezing,shortness of breath,dyspnea,cyanosis,clinical manifestations and chest imaging,the proportion of PICU admission,oxygen,mechanical ventilation,length of hospital stay relatively had no obvious difference(P>0.05).However,children mixed with MP were older than other groups,and the difference was statistically significant(P<0.05).Mixed with bacterial infection or MP infection was more likely to cause fever than virus co-infection(P<0.05);MP mixed bacterial infection was more likely to cause shortness of breath,high proportion of neutrophils and high CRP levels than MP mixed with virus infection(P<0.05).Part II.Risk factors of co-infections in children hospitalized with CAP Comparing the clinical features,pulmonary symptoms,family history,basic diseases and so on between the Single-pathogen infection and multi-pathogen co-infection,we found the eight factors,including congenital bronchopulmonary dysplasia,eczema history,wheezing history,more than 2 times of CAP hospitalization history,duration of hospitalization,high CRP levels,the increase of lgG and lgM in humoral immunity,was statistically significant(P<0.05).Then we performed the logistic-regression analyses revealing that congenital bronchopulmonary dysplasia,wheezing history,more than 2times of CAP hospitalization history were the independent risk factors for the occurrence of co-infection.Conclusions:1.Co-infection accounted for a certain proportion in children hospitalized with CAP,which always happened in autumn and winter.2.Two pathogens co-infection occupied the largest proportion.Virus-bacterial co-infection was the most commonly combination.HRV and RSV were the most commonly detected virus of co-infection while the Streptococcus pneumoniae,Haemophilus influenzae were the most commonly bacteria.HRV mixed with Streptococcus pneumoniae was the most identified pathogen of co-infection.3.The highest proportion of co-infection was in the age group of 6 months~1year old while the lowest proportion was in the age group of≥5 years old.There are different combinations among different age groups.4.The clinical characteristics of co-infections of different pathogens combinations were different.5.Congenital bronchopulmonary dysplasia,wheezing history,more than 2 times of CAP hospitalization history were the independent risk factors for the occurrence of co-infection.