Objective Antimicrobial resistance poses a serious threat to children's health. In recent years, high-risk Escherichia coli ST131 has become an important target for global surveillance studies. The E.coli ST131 clone is associated with extended spectrum β-lactamase (ESBL) production, as well as multidrug resistance and treatment failure. Studies on this clone in the pediatric age group are limited. We aim to investigate the rate of high-risk E. coli ST131 clone in ESBL-positive E. coli isolates obtained from pediatric patients.

Methods A total of 292 ESBL-positive E. coli isolates from clinical samples of pediatric patients was included in the study. MALDI-TOF MS system was used for bacterial identification. Susceptibility tests were performed using BD Phoenix automated system. ST131 detection was done by MALDI-TOF-MS. Fisher's exact test was used to compare the groups (significance <0.05).

Results A total of 292 isolates was analyzed. The high-risk ST131 clone was detected in 117 (40%) of the 292 ESBL-positive isolates. ST131 rates were found to be significantly higher in children under the age of 5 years compared with children over the age of 5 years (49.3 vs. 31.1%, p = 0.0019). Ciprofloxacin resistance was higher in ST131 isolates (45.6 vs. 31.7%; p < 0.05).

Conclusion The rate of the ST131 clone was found to be high in the pediatric population. The significantly high rate of resistance to ciprofloxacin, which is not commonly used in the pediatric population, in ST131 isolates reveals the importance of the spread of high-risk clones for the development of resistance.

目的 抗生素耐药性对儿童的健康构成严重威胁。近年来，高危大肠杆菌ST131已成为全球监测研究的重要目标。的大肠杆菌ST131克隆与广谱β内酰胺酶（ESBL）的生产，以及多药耐药性和治疗失败相关联。在儿科年龄组中对这种克隆的研究是有限的。我们的目的是调查从儿科患者获得的ESBL 阳性大肠杆菌分离物中的高风险大肠杆菌ST131 克隆率。

方法 本研究共纳入292株来自儿科患者临床样本的ESBL 阳性大肠杆菌分离株。MALDI-TOF MS系统用于细菌鉴定。使用 BD Phoenix 自动化系统进行敏感性测试。ST131 检测采用 MALDI-TOF-MS。Fisher 精确检验用于比较各组（显着性 <0.05）。

结果 共分析了 292 个分离株。在 292 个 ESBL 阳性分离株中的 117 个（40%）中检测到高风险 ST131 克隆。与 5 岁以上儿童相比，5 岁以下儿童的 ST131 发生率显着更高（49.3 对 31.1%，p  = 0.0019）。ST131 分离株对环丙沙星的耐药性更高（45.6% vs. 31.7%；p  < 0.05）。

结论 ST131 克隆率在儿科人群中较高。ST131 分离株对环丙沙星（在儿科人群中不常用）的显着高耐药率揭示了高风险克隆的传播对耐药性发展的重要性。