Clinical evaluation of laboratory diagnosis of Mycoplasma pneumoniae / 中华实用儿科临床杂志

ABSTRACT

Objective:To compare the laboratory diagnostic methods of Mycoplasma pneumonia(MP) and evaluate its clinical value.Methods:A prospective study.Throat swabs and double sera of children with MP infection were collected from December 2016 to January 2017 in Shengjing Hospital Affiliated to China Medical University; throat swab samples of healthy children aged 3 to 5 in Chaoyang District, Beijing were collected from March to May 2017.Passive agglutination (PA) was used to detect the double serum.Taking the 4-fold increase or decrease of the specific antibody titer of the double serum as the gold standard, the receiver operating characteristic curve (ROC) was drawn, and the laboratory methods for detecting MP infection were compared and evaluated.Results:(1)A total of 93 children with MP infection were clinically diagnosed, including 42 males (45.2%) and 51 females (54.8%), with an average age of 5.5 years.Sixty cases (64.5%) of MP infection were diagnosed.There were 349 healthy children, 198 males and 151 females, with an average age of 4.3 years.The positive rate of throat swab culture was 0.6% (2 cases), and the positive rate of fluorescent quantitative PCR(qPCR) was 18.9% (66 cases). (2) The culture specificity was the highest (100.0%) and the sensitivity was the lowest (65.0%). PA and enzyme linked immunosorbent assay (ELISA) were used to detect a single serum in the acute phase, the sensitivity was 71.7% and 86.5% respectively.ROC curve suggested that the current clinical diagnostic threshold MP specific antibody IgM ≥ 1∶160 was not the best diagnostic threshold.Molecular biological diagnostic methods were the most sensitive, RNA simultaneous and testing (SAT) was 85.0% and qPCR was 93.0%; while the specificity was low, 75.7% (SAT) and 63.6% (qPCR), respectively.(3) At the same time, MP nucleic acid (SAT, PCR) of throat swabs and a single serum (ELISA, PA) of children in acute phase were detected, the sensitivity was increased to 95.0%-100.0%, and the specificity was 63.6%-75.7%.Conclusions:Molecular biology is highly sensitive in diagnosing MP infection.It has asymptomatic infection or is carried after infection.Whether it needs treatment needs to be combined with clinical practice, when MP detection is positive.The detection of a single serum in the acute phase with a course of about 1 week has high sensitivity and is of reference value for the diagnosis of MP infection, but the diagnosis needs to be combined with clinical practice.The sensitivity and accuracy of detecting MP infection by single serological test combined with SAT in acute phase are higher than that by single application.