Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China.
Pediatr Pulmonol. 2019 Jul;54(7):1012-1021. doi: 10.1002/ppul.24327. Epub 2019 May 22.
To analyze the molecular and the clinical characteristics of Mycoplasma pneumoniae (Mp) pneumonia (MPP) and to explore the related factors predicting severe MPP (SMPP).
A total of 423 pediatric cases of MPP were retrospectively analyzed, in 2013-2017, in Beijing, China. Clinical information was collected from the medical records. Mp-positive specimens were characterized using P1 typing and multiple locus variable-number tandem repeat analysis (MLVA). The macrolide resistance-associated mutations were also detected.
The predominant genotype was P1-1 (88.2%) and M4-5-7-2 (87.5%), whereas percentages of type P1-2 and M3-5-6-2 increased across the 5-year period. The mutation rate of genotype M4-5-7-2 (365/370, 98.6%) was significantly higher than that of the genotype M3-5-6-2 (15/48, 32.25%; P = 0.000). Overall, 180 (42.6%) of the 423 Mp-positive patients were coinfected with other pathogens. Respiratory syncytial virus coinfection (24/180, 13.3%) was more common in cases typed M3-5-6-2 (4/23, 17.4%) than that of M4-5-7-2 (20/155, 12.9%; P = 0.038). Pleural effusion accounted for 52.6% (169/321) of the observed complications. In the mono-infection cases, cases typed M3-5-6-2 (56%, 14/25) were significantly (P = 0.020) associated with pleural effusion compared with those typed M4-5-7-2 (32.6%, 70/215); 84% (21/25) of specimens typed M3-5-6-2 were diagnosed as SMPP, whereas 63.7% (137/215) of specimens typed M4-5-7-2 were diagnosed as SMPP (P = 0.043).
In our study, we proposed for the first time that the mono-infection patients with Mp typed M3-5-6-2 appear to have a higher risk for progressing to SMPP. MLVA typing can provide hints on the clinical characteristics of Mpp.
分析肺炎支原体（MPP）肺炎的分子和临床特征，并探讨预测重症 MPP（SMPP）的相关因素。
回顾性分析 2013-2017 年北京地区 423 例儿科 MPP 病例，收集病历中的临床资料。采用 P1 型分型和多位点可变数目串联重复分析（MLVA）对 Mp 阳性标本进行特征分析。还检测了大环内酯类药物耐药相关突变。
主要基因型为 P1-1（88.2%）和 M4-5-7-2（87.5%），而 P1-2 和 M3-5-6-2 基因型的比例在 5 年期间有所增加。基因型 M4-5-7-2（370/370，98.6%）的突变率明显高于基因型 M3-5-6-2（48/48，32.25%；P=0.000）。总体而言，423 例 Mp 阳性患者中有 180 例（42.6%）合并感染其他病原体。呼吸道合胞病毒合并感染（24/180，13.3%）在 M3-5-6-2 型（4/23，17.4%）比 M4-5-7-2 型（20/155，12.9%；P=0.038）更为常见。胸腔积液占观察到的并发症的 52.6%（169/321）。在单纯感染病例中，M3-5-6-2 型（56%，14/25）明显（P=0.020）与胸腔积液相关，而 M4-5-7-2 型（32.6%，70/215）则不相关；84%（21/25）的 M3-5-6-2 型标本诊断为 SMPP，而 63.7%（137/215）的 M4-5-7-2 型标本诊断为 SMPP（P=0.043）。
在本研究中，我们首次提出 M3-5-6-2 型单纯感染患者似乎有更高的进展为 SMPP 的风险。MLVA 分型可为 MPP 的临床特征提供提示。
