目的 总结2023年4月至10月呼吸科住院儿童肺炎支原体（MP）感染流行病学特征和耐药率，并分析该段时期肺炎支原体肺炎（MPP）临床及治疗特征。方法 采集社区获得性肺炎患儿住院当日咽拭子标本，行tNGS病原体及MP大环内酯类耐药基因突变检测，分析MP阳性率及大环内酯类耐药率。MPP患儿根据所处月份分为平日组（6月）和流行高峰组（9月）；根据是否检出大环内酯类耐药基因分为敏感组和耐药组，比较各组间患儿临床特征。将耐药组分为平日耐药组和流行高峰耐药组，比较两组间治疗差异。结果 在1 425例社区获得性肺炎患儿中，男686例、女739例，中位年龄为6（3~8）岁。MP阳性率57.1%（813例）。4至10月各月份间MP阳性率差异有统计学意义（P<0.001），MP阳性率逐月上升（12.5%~71.6%）。813例MPP住院患儿中627例检出大环内酯类耐药基因突变，MP总耐药率为77.1%。MP非流行期（4~6月）的耐药率93.9%，流行高峰期（8~10月）耐药率显著降低，为71.9%。4至10月各月份间MP耐药率差异有统计学意义（P<0.001）。平日组76例，流行高峰组189例。与平日组相比，流行高峰组住院天数延长，CRP和LDH水平更高，差异有统计学意义（P<0.05）。敏感组64例，耐药组201例。与敏感组相比，耐药组住院天数延长，LDH水平更高，差异有统计学意义（P<0.05）。201例耐药MPP患儿中，平日耐药组71例，流行高峰耐药组130例。与平日耐药组相比，流行高峰耐药组应用甲基泼尼松龙后退热所需时间更长，四环素类抗生素使用率更高，差异有统计学意义（P<0.05）。结论 2023年8—10月为MP流行高峰，感染率高于平日，但住院患儿的MP耐药率低于平日。与平日相比，流行高峰期的MPP免疫应答反应更强，表现为更长的住院时间和更高的炎症指标，需考虑存在新突变的可能。大环内酯类联合糖皮质激素治疗对流行高峰期耐药MPP治疗效果欠佳，需要加用四环素类药物控制感染。

Objective To summarize the epidemiological characteristics and drug resistance rate of Mycoplasma pneumoniae (MP) infection in hospitalized children from April to October 2023, and analyze the clinical and therapeutic characteristics of MPP children during this period. Methods Throat swab samples of children with community-acquired pneumonia were collected on the day of hospitalization. The tNGS pathogen and MP macrolide-resistance gene mutation were detected, and MP positive rate and MP macrolide-resistance rate were analyzed. Patients with MPP were grouped by the admission date into non-epidemic group (June) and epidemic group (September), and further divided into resistant group and sensitive group in accordance to whether the macrolide-resistance genes were positive or not. The clinical features of the children were compared among the groups. The treatment differences were discussed comparatively between the non-epidemic resistant group and the epidemic resistant group. Results The median age of 1425 children (686 boys and 739 girls) with community-acquired pneumonia was 6 (3-8) years, and the MP positive rate was 57.1% (813 cases). The positive rate of MP varied significantly from April to October for each month (P<0.001), and MP positive rate increased month by month (12.5%-71.6%). Among 813 hospitalized children with MPP, 627 were positive for macrolide-resistance gene mutation, and the total drug resistance rate of MP was 77.1%. The drug resistance rate of MP was 93.9% in the period of non-epidemic (April to June), and significantly decreased to 71.9% in the epidemic period (August to October). The drug resistance rate of MP varied significantly from April to October for each month (P<0.001). There were 76 children in the non-epidemic group and 189 in the epidemic group. Compared with the non-epidemic group, the length of hospital stay were longer and the levels of CRP and LDH were higher in the epidemic group, with statistical significance (P<0.05). There were 64 children in the sensitive group and 201 in the resistant group. Compared with the sensitive group, the hospital stay was longer and the LDH level was higher in the resistant group, and the difference was statistically significant (P<0.05). Of the 201 children with macrolide-resistant MPP, 71 were in the non-epidemic resistant group and 130 were in the epidemic resistant group. Compared with the non-epidemic resistant group, the time to defervescence after methylprednisolone was longer and the use rate of tetracycline antibiotics was higher in the epidemic resistant group, and the difference was statistically significant (P<0.05). Conclusions The epidemic period of MP is from August to October 2023. Compared with normal days, the infection rate of MP is higher during the epidemic period, but the macrolide-resistant rate of MP in hospitalized children is lower. MPP during this epidemic period triggered stronger immune response, displayed as longer hospital stay and higher inflammatory factor level. The possibility of a new prevalent strain should be considered. This prevalent strain was less sensitive to combine treatment of macrolide plus corticosteroids, and tetracycline drugs are needed to control infection.