[Clinical characteristics of Mycoplasma pneumoniae infection and factors associated with co-infections in children].

Objective: To describe the clinical characteristics of Mycoplasma pneumoniae infection and analyze the factors associated with co-infections with other pathogens in children, and provide evidence for improvement of community acquired pneumonia (CAP) prevention and control in children. Methods: Based on the surveillance of hospitalized acute respiratory infections cases conducted in Soochow University Affiliated Children's Hospital (SCH), the CAP cases aged <16 years hospitalized in SCH between 2018 and 2021 were screened. The pathogenic test results of the cases were obtained through the laboratory information system, and their basic information, underlying conditions, and clinical characteristics were collected using a standardized questionnaire. The differences in clinical characteristics between M. pneumoniae infection and bacterial or viral infection and the effect of the co-infection of M. pneumoniae with other pathogens on clinical severity in the cases were analyzed; logistic regression was used to analyze the factors associated with the co-infections with other pathogens. Results: A total of 8 274 hospitalized CAP cases met the inclusion criteria. Among them, 2 184 were positive for M. pneumoniae (26.4%). The M. pneumoniae positivity rate increased with age (P<0.001), and it was higher in girls (P<0.001) and in summer and autumn (P<0.001). There were statistically significant differences in the incidence of wheezing, shortness of breath, wheezing sounds and visible lamellar faint shadow on chest radiographs, as well as fever and hospitalization days among M. pneumoniae, bacterial, and viral infection cases (all P<0.05). In the cases aged <60 months years, co-infection cases had higher rates of wheezing, gurgling with sputum and stridor; and in the cases aged ≥60 months, co-infection cases had a higher rate of shortness of breath (all P<0.05). Multifactorial logistic regression analysis showed that being boys (aOR=1.38,95%CI:1.15-1.67), being aged <6 months (aOR=3.30,95%CI:2.25-4.89), 6-23 months (aOR=3.44,95%CI:2.63-4.51), 24-47 months (aOR=2.50,95%CI:1.90-3.30) and 48-71 months (aOR=1.77,95%CI:1.32-2.37), and history of respiratory infection within 3 months (aOR=1.28,95%CI:1.06-1.55) were factors associated with co-infections of M. pneumoniae with other pathogens. Conclusions:M. pneumoniae was the leading pathogen in children hospitalized due to CAP. M. pneumoniae infections could cause fever for longer days compared with bacterial or viral infections; M. pneumoniae was often co-detected with virus or bacteria. Being boys, being aged <72 months and history of respiratory infection within 3 months were associated factors for co-infections.目的： 了解儿童肺炎支原体（Mp）感染的临床特征，分析Mp与其他病原体混合感染的相关因素，为完善儿童社区获得性肺炎（CAP）防治提供证据支持。 方法： 基于在苏州大学附属儿童医院（SCH）开展的急性呼吸道感染病例监测，筛选2018-2021年在SCH住院的<16岁CAP病例，采用统一的调查表收集研究对象基本情况、基础疾病史、临床表现等信息，通过医院检验信息系统查询研究对象的病原检测结果，比较Mp、细菌、病毒等病原体感染者的临床特征，比较Mp混合其他病原感染对病情严重性的影响，采用logistic回归模型分析Mp混合其他病原感染的相关因素。 结果： 共收集8 274名CAP住院病例，其中Mp阳性2 184例（26.4%）；Mp检出率女童高于男童（P<0.001），随月龄增加而升高（P<0.001），夏秋季高于冬春季（P<0.001）。喘息、气促、喘鸣音及肺部呈片状阴影的发生率，以及发热和住院天数等指标在Mp、细菌和病毒感染病例中的差异均有统计学意义（均P<0.05）。<60月龄Mp混合感染病例出现喘息症状及痰鸣音和喘鸣音的比例高于单纯感染病例，≥60月龄混合感染病例较Mp单纯感染更易出现气促症状（均P<0.05）。多因素logistic回归模型分析显示，男童（aOR=1.38，95%CI：1.15~1.67）、<6月龄（aOR=3.30，95%CI：2.25~4.89）、6~月龄（aOR=3.44，95%CI：2.63~4.51）、24~月龄（aOR=2.50，95%CI：1.90~3.30）、48~71月龄（aOR=1.77，95%CI：1.32~2.37）和3个月内呼吸系统感染史（aOR=1.28，95%CI：1.06~1.55）为Mp混合其他病原感染的相关因素。 结论： Mp是导致儿童CAP住院的主要病原体，单纯Mp感染病例较细菌、病毒感染病例发热天数更长；Mp常与细菌和病毒混合感染，男童、<72月龄和3个月内呼吸系统感染史是Mp混合感染的相关因素。.