Clinical Evaluation Of IRS-PCR In Detection Of Mycoplasma Pneumoniae Pneumonia

ObjectivesMycoplasma pneumoniae (MP) is a type of prokaryote with no cell wall,which is between viruses and bacteria.MP is not only one of an important pathogen which results in primary atypical pneumonia in children,but also the common pathogen resulting in community-acquired pneumonia in adults.In recent years,the incidence of MP is rising.Early,rapid diagnosis of MP infection has been placed great importance on.At present,the defects of culture and serological tests was low sensitivity, poor specificity, time-consuming.These two methods were prone to false positive and were not very good to meet the clinical needs.In recent years,it is possible to establish reliable,fast and early diagnosis of MP with the development of PCR technology.Touch-down PCR by Dr.Jensen and PCR by Dr.Alfred were the more common methods of detecting MP infection,They had higher sensitivity and specificity.In this study,we compared IRS-PCR with PCR by Dr.Jensen and PCR by Dr.Alfred to evaluate the clinical value of IRS-PCR.Methods1.Specimens source:A total of121cases children with acute respiratory tract infection in a hospital in Tianjin were selected.Throat swab specimens were collected by professional.MP DNA were extracted from throat swab specimens.2.PCR method:Patients with MP were detected by three PCR methods(IRS-PCR, PCR by Dr.Jensen,PCR by Dr.Alfred).The specimens of different results were to be sent to analyse the gene sequence.3.Sensitivity evaluation method:Ten fold serial dilutions of Mac DNA were made with ddH2O.We obtained10samples with different concentrations.IRS-PCR,PCR by Dr.Jensen and PCR by Dr.Alfred were applied in MP detection in10samples. The sensitivity of three methods can be measured.4.Specific evaluation method:Amplified by three PCR methods with14kinds of pathogen DNA as template.The specificity of the three PCR methods was determined with the results of2%agarose gel electrophoresis. Results1.IRS-PCR detected42positive cases,the positive rate was34.71%,46cases were positive by PCR by Dr.Jensen,the positive rate was38.01%,44cases were positive by PCR by Dr.Alfred,the positive rate was36.04%.There were four clinical specimens of12,15,21and30with inconsistent detection results.The four specimens were sent to be sequenced.Specimens of12and15were negative, specimens of21and30were positive.2.Sensitivity tests showed:The sensitivity of IRS-PCR and PCR by Dr.Alfred were higher than that of PCR by Dr. Jensen.3.Specific text showed:IRS-PCR amplified standard Mac and Escherichiastrains, other strains showed no specific bands,but the Escherichia coli specific band was mapped in about600bp,far away from the Mac specific band position, had no influence on the results decision,that is to say:it had no effection on the specificity of the IRS-PCR method.The other two methods only amplified specific bands of Mac, had no nonspecific band.This indicated that the specificity of the three methods was good.Conclusion1.By comparisoning IRS-PCR with PCR by Dr.Jensen and Dr.Alfred,the agreement rates of the three methods were high and the method had good concordance,so IRS-PCR can be used for clinical diagnosis of Mycoplasma pneumoniae pneumonia.2IRS-PCR had the advantage of easy manipulation, furthermore the specificity and sensitivity had no difference with PCR by Dr.Jensen and Dr.Alfred,so IRS-PCR can be popularized in domestic.