To study the presence and drug resistance of MP in throat swabs from ILI patients.

Throat swab specimens of 915 outpatients with ILI were collected from 17 grade A tertiary healthcare institutions in 15 regions of China (Weifang, Kaifeng, Harbin, Inner Mongolia, Beijing, Tianjin, Tongchuan, Xianyang, Qinhuangdao, Dandong, Hanzhong, Taiyuan, Benxi, Luohe, Nanyang) during two winters (one was from December 2018 to February 2019, and the other from December 2019 to February 2020) . The Influenza A+B Antigen Test Kit (Colloidal Gold) was used to identify influenza viral antigens. PCR was used to detect the nucleic acid from pneumonia pathogens. DNA sequencing was used to detect the drug-resistant gene associated with MP.

Of the specimens, 578 were from children (<18 years) and 337 from adults (≥18 years) . The overall detection rate of influenza viral antigens was 45.25% (414/915) . The positive rate of influenza A was 91.06% (377/414) . Pediatric and adult cases had no statistical difference in the detection rate of influenza viral antigens〔44.29% (256/578) vs 46.88% (158/337) , χ²=0.577, P=0.447〕. The overall detection rate of MP was 11.91% (109/915) . Pediatric and adult cases had no statistical difference in the detection rate of MP〔4.34% (25/578) vs 24.93% (84/337) , χ²= 86.094, P<0.001〕. Of the MP-positive specimens, 74.31% (81/109) had A2063G mutations, 1.83% (2/109) had A2064G mutations, and 1.83% (2/109) had A2063G and A2064G mutations. In children's MP-positive specimens, 48.00% (12/25) had A2063G mutations, 8.00% (2/25) had A2064G mutations, and 8.00% (2/25) had A2063G and A2064G mutations, the other 36.00% (9/25) had drug-susceptible strains. Of the adult MP-positive specimens, 82.14% (69/84) had A2063G mutation, 17.86% (15/84) had drug-susceptible strains, and no A2064G mutation was found. The rate of presence of drug-resistant gene A2063G mutations in adult specimens was higher than that in pediatric specimens (χ²=11.765, P=0.001) . Both influenza viruses and MP were detected in 2.84% (26/915) of the specimens. The rate of co-presence of influenza viruses and MP in adult specimens was higher than that in pediatric specimens〔4.75% (16/337) vs 1.73% (10/578) , χ²=7.022, P=0.008〕.

During winters in 2018—2020, influenza A was the major type of influenza prevailing in northern China. MP infection was not rare in patients with ILI, and it was more common in adults than in children. The resistance rate of MP to macrolide antibiotics was relatively high. A2063G mutation in the 23SrRNA gene was the major type of mutations. Some cases were coinfected with influenza viruses and MP.

研究ILI咽拭子标本中肺炎支原体（MP）的感染与耐药情况。

收集2018—2020年冬季（2018年12月至2019年2月、2019年12月至2020年2月）潍坊、开封、哈尔滨、内蒙古、北京、天津、铜川、咸阳、秦皇岛、丹东、汉中、太原、本溪、漯河、南阳地区共17家三级甲等医院中ILI咽拭子标本915份，采用流感病毒抗原胶体金法检测流感病原，荧光定量聚合酶链式反应（PCR）及DNA测序法检测MP核酸及耐药基因。

2018—2020年冬季915份ILI咽拭子标本中儿童标本（<18岁）578份，成人标本（≥18岁）337份。流感病毒抗原检测阳性率为45.25%（414/915），其中甲型流感病毒占91.06%（377/414）；儿童流感病毒抗原检测阳性率为44.29%（256/578），与成年人流感病毒抗原检测阳性率46.88%（158/337）比较，差异无统计学意义（χ²=0.577，P=0.447）。MP阳性率为11.91%（109/915），儿童MP阳性率低于成人〔4.34%（25/578） VS 24.93%（84/337），χ²=86.094，P<0.001〕。109份MP阳性标本中74.31%（81/109）存在A2063G位点突变，1.83%（2/109）存在A2064G位点突变，1.83%（2/109）存在A2063G位点和A2064G位点共同突变；儿童MP阳性标本中48.00%（12/25）存在A2063G位点突变，8.00%（2/25）存在A2064G位点突变，8.00%（2/25）存在A2063G位点和A2064G位点共同突变，36.00%（9/25）为敏感株；成人MP阳性标本中82.14%（69/84）存在A2063G位点突变，17.86%（15/84）为敏感株，未见A2064G位点突变；成人MP A2063G位点突变阳性率高于儿童（χ²=11.765，P=0.001）。915份ILI标本中流感病毒与MP混合感染阳性率为2.84%（26/915），儿童ILI标本中流感病毒与MP混合感染阳性率为1.73%（10/578），成人ILI标本中流感病毒与MP混合感染阳性率为4.75%（16/337），成人流感病毒与MP混合感染阳性率高于儿童（χ²=7.022，P=0.008）。

2018—2020年我国北方地区冬季流感以甲型流感为主，ILI标本中MP感染并不少见，成人ILI样本中MP阳性率高于儿童，MP对大环内酯类抗生素的耐药率仍处于较高水平，并且以23SrRNA基因A2063G位点突变为主，部分患者可见流感病毒与MP混合感染。