Inflammation Characteristics And Relative Factors Of Severe Mycoplasma Pneumoniae Pneumonia In Children

Part1Inflammation characteristics of severe mycoplasma pneumoniae pneumonia in childrenObjective:(1) To investigate inflammation characteristics and predictive factors of severe mycoplasma pneumoniae pneumonia(SMPP)in children.(2) To explore the dynamic changes of clinical inflammatory indicators before and after Glucocorticoid treated in severe mycoplasma pneumoniae pneumonia(SMPP)in children, so as to recognize and treat the disease earlier.Method:(1) A retrospective study of clinical and laboratory characteristics of one hundred and ninety children with MPP was performed in Children's Hospital of Fudan University from July2012to December2012. A total of190patients were grouped by severity of MPP:40children with severe MPP and150children with common MPP. The data including age, sex, febrile time, radiological features and inflammatory markers (WBC,N ratio,CRP,ESR,LDH,IL-6,PCT) of those children were analyzed. The inflammation variables which had significant difference in one-way anova analysis was analyzed by receiver operating characteristic (ROC) curve to find out the cut-off value for the significant relevant factors.(2) To study the dynamic changes of serum CRP in25severe MPP patients who had received glucocorticoids treatment, and find out its change rule. Result:(1) Severe MPP patients:most children over5years old (65%), febrile time was more than7days, X-ray showed lobar pneumonia. Common MPP patients:most children under the age of5(66%), febrile time was5-10days, bronchopneumonia was the main X-ray pattern (85%)(2) Compared with Mild MPP group, inflammatory markers(neutrophil ratio, CRP, ESR, LDH, IL-6and PCT) in Severe MPP group increased significantly (P<0.01). Predictive factors for Sever MPP were CRP, ESR, LDH, IL-6, PCT(area under the ROC curve=0.90?0.673?0.633?0.74?0.732), and the best threshold of CRP was22.5mg/L which were demonstrated by ROC curve analysis.(3) The first clinical day is defined as the first day of fever. The value of CRP on initial test was14.0(8.0-35.8) mg/L at5.0(2.0?10.0)clinical days, was increased to maximum value was52.0(25.5?77.0) mg/L at9.0(3.0?16.0) clinical days, and was decreased to follow-up value was8.0(8.0?12.8) mg/L at17.0(10.0?27.0) clinical days.Conclusion:(1) All data in this study show that there are powerful inflammatory responses during early period of SMPP pathogenesis, and the cut-off value of CRP has the highest diagnostic accuracy.(2) Regular follow-up of CRP is essential for patients with MPP who aged5years of age or older and fever for5(2-10) days. Doctors should remain on high alert for severe MPP if CRP was increased to22.5mg/L, but most patients had good prognosis if Glucocorticoid has been early used.Part2Relation clinical severity of mycoplasma pneumonia pneunonia with bacterial load of Mycoplasma pneumoniae in oropharyngeal secretions Objective:This study aims to determine whether MP bacterial load in airway secretions associated with disease severity and level of inflammation response of children with MPP.Method:Clinical samples were collected by nasopharyngeal aspiration from children with MPP hospitalized in the Children's Hospital of Fudan University from July to December in2012. MP bacterial load was measured by Fluorescence quantitative polymerase chain reaction (FQ-PCR). A total of190patients with MPP were grouped by bacterial load:low bacterial load group (103-105copies/ml), and high bacterial load group (?106copies/ml). The data including age, sex, febrile time, radiological features and inflammatory markers (CRP,ESR,LDH,IL-6,PCT) of190children were retrospectively analyzed.Result:(1) The method of FQ-PCR to detect MP16S rRNA gene in nasopharyngeal no difference in bronchoalveolar lavage fluid (BALF)(2) Compared with low bacterial load group, the incidence of lobar pneumonia and inflammatory markers(CRP, LDH, IL-6and PCT) in high bacterial load group increased significantly (P<0.01). Patient's age, sex, clinical days on admission, febrile time and ESR in two groups showed no significant difference (P>0.05).(3) The copies of MP16SrRNA gene in Severe MPP group were significant higher than those in common MPP group (P<0.01). The diagnostic value of copies of MP16SrRNA gene in severe MPP by ROC curve analysis (area under the ROC curve=0.703).The specificity and sensitivity for this diagnostic test were respectively0.5-0.7and0.6-0.8at copies of MP16SrRNA gene cut off of106copies/ml.(4) The copies of MP16SrRNA gene were positively correlated with CRP?IL-6?PCT (r=0.366,0.28,0.254, P<0.01), and this association persisted in children under the age of five (r=0.311,0.303,0.222,P<0.05), but there were no significant relation between those copies and inflammatory markers in children over5years old(P>0.05). Conclusion:(1) The copies of MP-DNA may be regarded as an indicator of the disease severity and therapeutic effect.(2) The copies of MP16SrRNA gene were positively correlated with levels of inflammation in children under the age of five, treatment focuses on the MP bacterial load reduction might be good for reduce inflammation.Part3Relation clinical severity of Mycoplasma pneumoniae pneumonia with mycoplasma pneumoniae genotype in oropharyngeal secretionsObjective:(1) To identification of Mycoplasma pneumonia (MP) genotype during an epidemic in shanghai.(2) To explore the relation clinical severity of Mycoplasma pneumonia (MP) pneumonia with MP genotype.Method:Nasopharyngeal aspirate (NPA) were collected from children with MP infected in Children's Hospital of Fudan University during the period from July to December in2012. We genotyped the PI gene in201specimens whose concentration was1.0*105copies/ml or above. Randomly selected the6PI type1specimens,3PI type2specimens and the reference strain MP-FH to sequence. According to inclusion criteria and exclusion criteria of mycoplasma pneumoniae pneumonia, all the116children were involved in the analysis of clinical datas.Result:(1) After PCR-RFLP analied, we found that191clinical specimens showed the banding pattern characteristic for P1type1, and only10clinical specimens and the reference strain MP-FH showed the banding pattern characteristic for P1type2.(2) After sequencing, the sequences of the PI typel specimen showed very high similar to MP129, and the sequences of the P1type2specimen showed very high similar to MP-FH. Point mutations was identified in the half of6P1typel specimens, but Point mutations was identified in the all3P1type2specimens.(3) All the cases with P1type2MPP showed common pneumonia, but80cases with P1type1MPP showed common pneumonia and30cases with P1type1MPP showed severe pneumonia. Compared with the cases with P1type2MPP, the cases with P1type1MPP have more longer febrile time (P<0.05), but age,sex,clinical days on admission,radiological features,inflammatory markers and the copies of MP-DNA had no significant difference between two groups (P>0.05).Conclusion:(1) Clinical samples can be used directly for genotyping of MP, the dominating type of MP in Shanghai city was P1type1.(2) Whether there was any relationship between MP genotype and clinical severity remains to be clarified.