Study And Investigation On Incidence Of Mycoplasma Bacteremia In Children With Mycoplasma Pneumoniae Pneumonia

Background:Mycoplasma pneumoniae(M.peumoniae)is one of the most common human pathogen that causes community acquired pneumonia(CAP)among children and young adults worldwide.This bacterium accounts for more than 50%of CAP in children above 5 years,and is recognized as the major causative agent of respiratory infection in childhood which causes both upper and lower respiratory tract infections.In addition to respiratory symptoms,M.pneumoniae can also cause non-respiratory diseases.The pathogenesis of M.pneumoniae infection is complicated and not fully understood.The study done by Daxboeck in 2005 proposed that M.Pneumoniae was present in blood circulation in considerable portion of patient with mycoplasma pneumonia and concluded that the prevelance rate of bacterima is 52%.Furthermore,many researches have reported that bacteremia predisposes to extra pulmonary complications and in clinical practice we do see the patients with mycoplasma pneumonia have extra pulmonary manifestations.Hence we assume that M.pneumoniae exists in blood stream and leads to mycoplasma bacteremia.However,the studies done in China have shown that the prevalence rate of mycoplasma bacteremia is considerably low.In 2010,research done by Wang Hong Bo reported that MP DNA positivity rate in serum PCR was 20.8%.Later in 2013,Zhao Qi Lin found that the detection rate of MP in serum was 36.5%and the detection rate in the study of Li HaiPing et al.(2015)was 31.7%.So,this study is proposed to confirm the existence of mycoplasma bacteremia in mycoplasma pneumonia patients by using the blood RT PCR assay and focused on examining the exact prevalence rate of mycoplasma bacteremia in the children with mycoplasma pneumonia.Methods:The study was conducted from January 2018 to May 2018 in the department of pediatric pulmonology,First Hospital of Jilin University,Changchun,China.Serologically confirmed cases of M.pneumonia were investigated in the study.The antibodies(IgG)against M.pneumoniae were examined by using the particle agglutination assay Serodia-Myco ? kit.The IgG titre of ?1:160 was considered positive.Blood samples were collected from patients and the samples obtained from these patients were sent to the Laboratory of Molecular Biology,Gene Diagnostics Center of First Hospital of Jilin University for the detection of M.pneumoniae.Mycoplasma DNA from plasma and WBC(lymphocytes separated from WBC)were extracted by using M.pneumoniae DNA detection kit(PCR fluorescence probe method).M.pneumoniae DNA present in these samples(plasma and WBC)was amplified by real time PCR using M.pneumoniae PCR Fluorescence Diagnostic Kit.Finally,clinical features,fever pattern,severity of disease condition,complications and laboratory findings were compared in between blood PCR positive patients(mycoplasma bacteremia)and PCR negative M.pneumoniae pneumonia patients.Statistical analyses were performed using IBM SPSS statistics 18.Objective:Firstly,the study aims to examine prevalence of bacteremia in children with Mycoplasma pneumoniae.Real time PCR(RT PCR)was performed both on plasma and WBCs(lymphocytes separated from whole blood)in parallel.Secondly,this study is conducted to examine the PCR positivity rate of Mycoplasma Pneumoniae DNA in these two different blood specimens(plasma and lymphocyte separated from WBC).Finally,the study aims to compare clinical manifestations(including age difference,fever withdrawal time,hospital stay duration,complications)between blood PCR positive patients(mycoplasma bacteremia)and negative mycoplasma pneumonia patients.Results:In this study,75 children diagnosed with mycoplasma pneumonia through serological tests were enrolled.Blood samples obtained from these children were subjected to real time PCR.M.pneumoniae was detected in 53.33%(40/75)in whole blood samples.In this study,M.pneumoniae DNA was detected in 19 out 40(47.5%)plasma specimen,in 10/40(25%)WBC specimen and 11 out of 40(27.5%)samples were positive for both plasma and WBCs.There were no significant statistical differences observed according to sex(p =0.432),age(p=0.245)and fever withdrawal duration(p=0.565)in M.pnezumoniae DNA positive group and negative group.The differences in time period of patients staying in hospital in two groups was statistically significant(p=0.042).In mycoplasma bacteremia positive group,days of hospital stay mean±SD(9.75±3.04)was longer than in mycoplasma DNA negative group(7.88±2.05).Hence,significant statistical differences were found between two groups with regards to time period of patient's hospitalization.There were no significant difference found between M.pneumoniae DNA PCR positive group and negative group with regards to WBC(p=0.854),neutrophils(p =0.058),monocytes(p=0.214),RBC(p=0.316),Hb(p =0.511),platelets(p=0.134),creatinine kinase(CK)(p=0.246),creatinine kinase iso-enzyme CKMB(p=0.417),LDH(p=0.161).In the present study,CRP level was statistically significant(P=0.004).Mycoplasma bacteremia positive group showed considerably higher mean ±SD(37.82±70.70)than in the PCR negative group mean ±SD(13.59±17.89).Similarly,this study demonstrated significant differences in liver function test with AST p value 0.011 and ALT p value 0.001.In mycoplasma bacteremia positive group,AST mean ±SD(54.03±63.48)and ALT mean ±SD(33.44±38.22)was higher than in PCR negative group(36.93± 12.57,21.11±14.82).In M.pnezumoniae DNA positive group,59.45%(22/37)of patient had pulmonary and/or extra pulmonary complications.Among these 22 patients,24.33%(9/37)of patients had acute myocardial injury which was the most common complication.Severe pneumonia and/or pleural effusion were observed in 13.51%(5/37).8.10%(3/37)had acute hepatic injury.In contrast,in M.pnezumoniae DNA PCR negative group,only 38.23%(13/34)of patients had pulmonary and/or extra pulmonary complications.The most common complication was acute myocardial injury found in 17.64%(6/34),followed by severe pneumonia with pleural effusion in 5.82%(2/34).5/35(11.64%)were other complications such as Kawasaki disease,infectious mononucluesus,acute follicular tonsillitis and sepsis.Conclusions:In conclusion,this study showed that M.pneumoniae is present in blood stream of significantly higer proportion of patient with M.Pneumoniae pneumonia.The use of blood based PCR method to detect M.Pneumoniae bactereia could generate useful data to understand prevalence of mycoplasma bacteremia observed in pneumonia patients.This would enhance our understanding of mycoplasma bacteremia prevalence,relationship between co-existence of mycoplasma bacteremia with extra pulmonary manifestation.