220例住院肺炎患儿肺炎支原体的分子检测及其基因分型研究

Molecular detection and genotyping of Mycoplasma pneumoniae in 220 children hospitalized with pneumonia

摘要:

目的：通过检测社区获得性肺炎患儿支气管肺泡灌洗液了解肺炎支原体（MP）感染情况及基因分型特点。方法：采用聚合酶链反应（PCR）方法对220例住院肺炎患儿支气管肺泡灌洗液进行MP检测，用荧光定量PCR方法验证结果的准确性；将检测阳性标本用Hae Ⅱ 和Hae Ⅲ 两种限制性内切酶进行酶切反应后与标准株对比，分析阳性标本MP的基因分型。通过随机采样对部分阳性标本扩增产物测序证实基因分型的准确性。结果：220份标本MP的阳性检出率为55.0%（121/220）。MP感染好发于学龄前期和学龄期儿童（63.5%，101/159），6个月内的婴儿阳性率最低20%（1/5），无明显性别差异和季节差异。随机抽取的60份MP阳性标本经酶切反应均显示为P1-Ⅰ型，4份测序结果也证实其为P1-Ⅰ型。结论：MP是肺炎患儿的重要病原之一，有明显的年龄特征；流行型以P1-Ⅰ型为主。

Abstract:

OBJECTIVE: To investigate the infection rate and genotypes of Mycoplasma pneumoniae (MP) by examining bronchoalveolar lavage fluid from children with community acquired pneumonia (CAP). METHODS: Polymerase chain reaction (PCR) was used for detecting MP in bronchoalveolar lavage fluid from 220 children hospitalized with CAP, and the accuracy was confirmed by quantitative real-time PCR. Positive samples were digested with HaeⅡ and Hae Ⅲ and compared with standard strain to analyze the genotypes of MP from positive samples. The accuracy of genotyping was confirmed by sequencing the amplified products of some randomly selected positive samples. RESULTS: The positive rate of MP in 220 samples was 55.0% (121/220). MP infection occurred mostly in preschool and school-age children (63.5%, 101/159), and the lowest positive rate was seen in children aged under 6 months (20%, 1/5). The positive rate showed no significant differences between sexes and between seasons. Sixty randomly selected MP-positive samples showed a genotype of P1 type 1 after restriction digestion, which was further confirmed by sequencing of 4 samples. CONCLUSIONS: MP is one of the main pathogens of pneumonia in children, and the MP infection rate is significantly correlated with age. The dominant genotype of MP in children is P1 type 1.