Significance of dynamic detection of MP-DNA and IgM in the course of mycoplasma pneumoniae infection in children

Abstract

Objective To explore the values of FQ-PCR for detecting MP-DNA and DIGFA for MP-IgM in the diagnosis of mycoplasma pneumoniae( MP ) infection in children.Methods Respiratory secretions and serum samples were collected.MP-DNA in respiratory secretions was detected by FQ-PCR and serum MP-IgM by DIGFA.Children with positive MP-DNA or MP-IgM alone or both MP-DNA and MP-IgM were diagnosed as MP infection.The changes in the positive rates of MP-DNA and MP-IgM during different courses were observed and analyzed.Results 56 children were diagnosed as MP infection.In the early disease course,the positive rate of MP-DNA was 82.14％ ( 46/56 ),and that of MP-IgM was 35.71％ ( 20/56 ); the former was significantly higher than the latter,with a significant difference ( P＜ 0.05 ).In the middle disease course,the positive rate of MP-DNA dropped to 64.29％ ( 36/56 ),while that of MP-IgM increased to 80.36％ ( 45/56 ); In the recovery course,the positive rate of MP-DNA continued to decline to 1.79％ ( 1/56 ),while that of MP-IgM decreased to 23.21％ ( 13/56 ).Conclusions In children with MP infection, MP-DNA is gradually decreased with the prolongation of the disease course,while MP-IgM is increased until to the middle course and then is declined.FQ-PCR for MP-DNA has a greater value in the diagnosis of MP infection at the early stage,while DIGFA for MP-IgM has a diagnostic significance for the children who has a longer disease course and makes a first visit.Combination of two methods is beneficial for the diagnosis and can be used for prediction of the disease outcome. Key words: FQ-PCR; Mycoplasmapneumoniae; MP-DNA; MP-IgM