The Role Of Mycoplasma Pneumoniae In Children With Lobar Pneumonia In Soochow Area

Objective: We aimed to investigate the etiological feature of the children with lobarpneumonia in Soochow area and to explore the epidemiological characteristic and itsclinical and laboratory features of mycoplasma pneumoniae(MP) infection in thosechildren.Methods:425Children diagnosed with community acquired pneumonia wereenrolled in this investigation.All the subjects were hospitalized in respiratory department inChildren’s Hosptital of Soochow University and Soochow Wuzhong People’s Hospitalduring January2009to December2012,and their X-rays all showed lung blockbusterconsolidation shadows or segmental change.We collected their fresh sputum by sterilesuction method.The MP-DNA level was detected by polymerase chain reaction(PCR),thehMPV level was detected by reverse-transcription polymerse chain reaction(RT-PCR),andthe HBoV level was detected by real-time PCR.The level of respiratory syncytialvirus,influenza virus A and B,parainfluenza viruses1to3,and adenovirus were detected byfluorescent antibody test.And all the specimens were taken culture bacteriologicalexamination.MP-IgM and IgG were detected by quant ELISA in paired serum specimens.Subjects with double positive of MP antibody and/or serum MP-DNA by PCR weredefined as MP infection.According to the etiological results,the subjects were divided intosingle MP infection group(263cases),non-MP infection group(93cases),MP coinfectionwith other pathogens group(20cases),and unknown pathogens group(49cases).Wecollected all the clinical and laboratory data and analyzed them by retrospective statisticalmethods.Results:(1) Epidemiological characteristics:66.59%(283/425) children with lobar pneumoniahad evidence of MP infection in Soochow area during2009-2012and there was anincreasing trend.MP could be detected in every month.We detected more cases with MPinfection in winter and spring than those in summer and autumn(P<0.001).Apart from MP, other pathogens detected were Streptococcus pneumonia(5.88%),Staphylococcus aureus(4.00%),Haemophilus influenza (2.82%),Moraxelle catarrhalis(2.82%),Parinfluenzaviruses(1.65%),Adenovirus (0.94%) and Acinetobacter baumannii(0.47%).(2) The clinical features:The average age of single MP infection group was5.92(3.00-7.67)years,and it was higher than that of non-MP infection group (P<0.01).MPdetection rate in over-5-year-old age group was up to90.76%(167/184) in each agegroup.There was no difference in MP detection rate betweeen boys and girls.Comparedwith non-MP infection group,single MP infection group had more symptoms like coughingmore than30days (22.81%),having fever for more than10days(23.19%), wheezing(22.05%) and pleural effusion(12.93%).MP coinfection group had more chance to havesymptom like fever(90.00%),shortness of breath (30.00%), cyanosis(15.00%), atelectasis(35.00%),pleural effusion(35.00%),pulmonary function abnormalities(60.00%), moistrales(95.00%) and severe cases(30.00%) than simple MP infection group.(3) Laboratory findings:The white blood cell count、cellular immunity and humoralimmunity were normal in single MP infection group、non-MP infection group and MPcoinfection group.But their CRP levels were high.The increase of CRP in MP coinfectiongroup was higher than that of single MP infection group and non-MP infection group.MPinfection could cause elevated ALT,but there was no significant difference compare tonon-MP infection group.X-ray results showed MP detection rate in right lower lung field isthe highest in each field,accounting for85.19%(92/108).Conculsion:(1) MP was one of the most important pathogen in children with lobarpneumonia in Soochow area and had the highest detection rate in multi-pathogendetection.(2) MP infection could be seen through the whole year in lobar pneumonia.Theinfection rate was higher in winter and spring than that in summer and autumn.The averageage of single MP infection group was higher than that of non-MP infection group and theMP detection rate was the highest in over-5-years-old group.(3) MP infection may causeprolonged cough,persistent fever, increased wheezing and increased proportion of pleuraleffusion.(4) MP detection rate in right lower lung field was the highest in each field.(5)The clinical symptoms were severer in MP coinfection group than that in single MPinfection group.There were many complications and difficulties during the treatment.Moreattention should be paid to that.