Analysis of antibody detection data of Mycoplasma pneumoniae in a hospital in Beijing City from 2017 to 2024

Objective  To explore the distribution characteristics of Mycoplasma pneumoniae (MP) antibody detection data in our hospital, provide data reference for the prevention and control of MP infections. Methods  A single-center retrospective study was conducted on patients (aged 0 to 105 years) with suspected MP infection from the outpatient, emergency and inpatient departments of Peking University Third Hospital between March 2017 to February 2024. MP antibodies in patient serum were detected using passive agglutination. χ² was used to analyze the differences in the positive rate of MP antibodies among different genders, ages, and seasons. Results  Among the 20,639 patients, the positive rate of MP antibodies was 23.19%, with a higher positive rate in females (27.16%) compared to males (19.90%)(χ²=151.191, P<0.01). The positive rate in children (37.13%) was significantly higher than in adults(15.47%, χ²=1,246.433, P<0.01). The 6 to <12 year age group (63.11%) had the highest positive rate of MP antibodies, followed by 12 to <18 year old group (56.78%). The positive rate of MP antibodies increased with age from 0 to 12 years old but gradually decreased after 12 to <18 years old (P trend<0.01). The annual MP antibody positivity rates from 2017 to 2023 were 26.92%, 29.23%, 27.46%, 18.43%, 17.16%, 11.89%, and 23.72%, respectively, with statistically significant differences among the years (χ² = 387.519, P < 0.01). The combined positivity rate was highest in the autumn season (χ² = 242.560, P < 0.01). The positive rates of MP antibodies before the epidemic (2017-2019), during the epidemic (2020-2022), and after the epidemic (2023-2024) were 28.00%, 16.60%, and 21.84%, respectively, with statistically significant differences among the three periods(χ²=295.845, P<0.01).The monthly positive rate of MP fluctuated significantly in different years (5.63% to 43.11%). In the MP antibody titer, qualitative testing was conducted on 4,563 patients and 16,076 patients had a semi-quantitative MP antibody titer of ≥1:160 with a positive rate of 16.03%. Among the proportion of children with high titers of MP antibodies ≥1:1,280 was 11.11%. Conclusion  The positive rate of MP antibodies in Peking University Third Hospital varies by gender, age, and season. The infection shows periodic epidemic changes with a peak in autumn, mainly affecting children and adolescents.

目的 本研究旨在探讨北京大学第三医院肺炎支原体（Mycoplasma pneumoniae, MP）抗体检测数据的分布特征，为肺炎支原体感染的防控工作提供数据参考。
方法 本研究为单中心回顾性研究，研究对象为2017年3月至2024年2月期间，北京大学第三医院门诊、急诊及住院科室中疑似肺炎支原体感染的患者（年龄0~105岁）。采用被动凝集法检测患者血清中的MP抗体。使用χ²检验分析不同性别、年龄组及季节的MP抗体阳性率差异。
结果 纳入20639例患者，其MP抗体总阳性率为23.19%；其中女性阳性率（27.16%）高于男性（19.90%），差异具有统计学意义（χ²=151.191，P<0.01）。儿童MP抗体阳性率（37.13%）显著高于成人（15.47%，χ²=1246.433，P<0.01）。6~<12岁年龄组MP抗体阳性率最高（63.11%），其次为12~<18岁年龄组（56.78%）；MP抗体阳性率在0~12岁随年龄增长逐渐升高，12~<18岁后则逐步降低（P趋势<0.01）。2017-2023年各年度MP抗体阳性率分别为26.92%、29.23%、27.46%、18.43%、17.16%、11.89%及23.72%，各年份阳性率差异具有统计学意义（χ²=387.519，P<0.01）。秋季MP抗体总阳性率最高（χ²=242.560，P<0.01）。疫情前（2017-2019年）、疫情期间（2020-2022年）及疫情后（2023-2024年）的MP抗体阳性率分别为28.00%、16.60%及21.84%，三个时期阳性率差异具有统计学意义（χ²=295.845，P<0.01）。不同年份的MP抗体月阳性率波动幅度较大（5.63%~43.11%）。针对MP抗体滴度，共对4563例患者进行定性检测，16076例患者的半定量MP抗体滴度≥1:160，阳性率为16.03%；其中抗体滴度≥1:1280的儿童高滴度比例为11.11%。
结论 北京大学第三医院MP抗体阳性率存在性别、年龄及季节差异。该感染呈现周期性流行特征，秋季为流行高峰，主要感染人群为儿童及青少年。