Objective: To explore the drug resistance of Isolated From Blood Culture Escherichia coli (E. coli) in a hospital in Qinghai over the past seven years, to evaluate the ability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to analyze the homologous origin of E. coli, and to establish a protein fingerprint library to match with it, adjuvant clinical experience medication so as to provide the basis for the prevention and control of hospital-acquired infections. Methods: Retrospective analysis of blood cultures sent to hospitals from January 2016 to December 2022. Drug resistance and resistance changes in E. coli.A total of 1 841 E. coli strains were isolated from Qinghai Provincial People's Hospital from January 2016 to December 2022; all strains were identified by MALDI-TOF MS, and the VITEK2.0 drug sensitivity analyzer was applied for drug sensitivity analysis of the strains, and the mass spectrometry homology analysis and self-constructed protein fingerprint library were carried out by MALDI-Biotyper software; the protein fingerprint library was built by using WHONET5.6 software was used to statistically analyze the drug sensitivity results, SPSS23.0 software was used to analyze the relationship between fingerprint typing and drug sensitivity, and the χ2 test was used for intergroup comparisons. Results: A total of 1 841 strains of E. coli were detected in 4 582 positive blood culture specimens from January 2016 to December 2022, with a detection rate of 40.17%; the resistance rate of E. coli from blood sources to piperacillin/tazobactam and ceftriaxone was on the rise, and it was slightly decreased to cefepime, amikacin, levofloxacin, and sulfamethoxazole, and there was not much change to the rest of the drugs; After MALDI-Biotyper clustering analysis, the 1841 E. coli strains from Isolated From Blood Culture were classified into two major clusters and five subtypes, of which type Ⅰa1 accounted for about 40%, type Ⅰa2 accounted for about 2.7%, type Ⅰb accounted for about 3.8, type Ⅱa accounted for about 46%, and type Ⅱb accounted for about 7.5%. The detection rate of type Ⅰa1 E. coli was higher in general surgery (50.45%) and emergency surgery (50.92%), and the detection rate of type Ⅰb E. coli was higher in emergency medicine(10.05%)than in other departments. The drug sensitivity results of different subtypes were compared with each other, the resistance rate of type Ⅰa1 E. coli to cefepime was 21.3% higher than that of the remaining four types, and the difference was statistically significant (χ2=37.74,P=0.000); the resistance rate of type Ⅱ E. coli(>60%) to sulfamethoxazole was higher than that of type Ⅰ (<60%) as a whole, and the difference was statistically significant (χ2=15.248,P=0.004); and a preliminary database of homologous protein fingerprints of E. coli has been established E. coli homologous protein fingerprint library and validated. The drug susceptibility results of 1 288 E. coli strains in the validation set were statistically analyzed and compared with those in the training set. There was no significant difference(P>0.05). Conclusion: In recent years, the resistance rate of E. coli isolated from a hospital in Qinghai province to piperacillin/Tazobactam, cefepime, amicacin and other antibiotics has changed greatly. A fingerprint database of E. coli homologous protein was established, and it was found that the drug sensitivity data of E. coli were different among different fingerprint types. According to drug sensitivity, drug use could assist clinical experience and provide evidence for prevention and control of hospital illness.
目的： 探讨血培养分离大肠杆菌（E. coli）的耐药情况，评价基质辅助激光解吸/电离飞行时间质谱技术（MALDI-TOF MS）对E. coli同源性分析能力，并建立与之匹配的蛋白指纹库，辅助临床经验用药，为院感防控提供参考依据。 方法： 回顾性分析2016年1月至2022年12月医院送检血培养E. coli的耐药性及耐药变迁情况；收集2016年1月至2022年12月青海省人民医院血培养分离E. coli 1841株；所有菌株均采用MALDI-TOF MS进行鉴定，应用VITEK2.0药敏分析仪对菌株进行药敏分析，并用MALDI-Biotyper软件进行质谱同源性分析及自建蛋白指纹库；利用WHONET5.6软件统计药敏结果，利用SPSS23.0软件分析指纹分型与药敏结果之间的关系，组间比较采用χ2检验。 结果： 2016年1月至2022年12月4 582份血培养阳性标本中共检出E. coli 1 841株，检出率为40.17%；血培养分离E. coli对哌拉西林/他唑巴坦和头孢曲松的耐药率呈上升趋势，对头孢吡肟、阿米卡星、左旋氧氟沙星和磺胺甲恶唑略有下降，对其余药物变化不大；经MALDI-Biotyper聚类分析，将血培养分离的 1 841株E. coli分为两大簇五个亚型，其中Ⅰa1型约占40%、Ⅰa2型约占2.7%、Ⅰb型约占3.8、Ⅱa型约占46%、Ⅱb型约占7.5%。Ⅰa1型E. coli在普外科（50.45%）和急诊外科（50.92%）的检出率较高，Ⅰb型E. coli在急诊内科检出率（10.05%）高于其他科室。不同分型之间的药敏结果相互比较，Ⅰa1型E. coli对头孢吡肟的耐药率21.3%高于其余四型，差异有统计学意义（χ2=37.74，P=0.000）；Ⅱ型E. coli对磺胺甲恶唑的耐药率（>60%）整体高于Ⅰ型（<60%），差异有统计学意义（χ2=15.248，P=0.004）；初步建立了E. coli同源性蛋白指纹库并进行验证。将验证集中1 288株E. coli药敏结果进行统计，并与训练集的药敏结果进行比对，差异均无统计学意义（P>0.05）。 结论： 本研究血培养分离E. coli对哌拉西林/他唑巴坦、头孢吡肟、阿米卡星等抗菌药物的耐药率变化较大；建立E. coli同源性蛋白指纹库，发现不同指纹分型E. coli的药敏数据有差异，依据药敏数据可以辅助临床用药。.