Second Department of laboratory, Hunan Provincial People's Hospital (The First Affiliated Hospital of Hunan Normal University), Changsha, Hunan410006, China.
Cell Mol Biol (Noisy-le-grand). 2022 Jun 30;68(6):67-72. doi: 10.14715/cmb/2022.68.6.11.
This experiment was carried out to provide a basis for the treatment of clinical bloodstream infections by analyzing the drug resistance characteristics and integrated gene distribution of Escherichia coli in bloodstream infections in elderly patients. For this aim, E. coli were collected for bacterial identification and drug sensitivity testing from bloodstream infections in elderly patients in the hospital from January 2016 to December 2019. ESBLs positive strains were assayed for genotypes and their integron carriage rates by PCR amplification. The characteristics and differences of various genotype rates were compared and analyzed. Results showed that a total of 230 E. coli strains were isolated. The detection rate of ESBLs-producing bacteria was 37.39 %. ESBLs-producing E. coli showed a high rate of resistance to cefepime, levofloxacin, cotrimoxazole, and ticarcillin/clavulanic acid (>40%). The resistance rate of 230 strains of E. coli to meropenem, minocycline, amikacin, gentamicin and cefoxitin was less than 20%. Among the ESBLs-producing E. coli in bloodstream infections in elderly patients, CTX-M-9 accounted for 27.91%, CTX-M-2 for 17.44%, and SHV for 13.95%. The detection rate of type I integrated genes was 41.30%, and type II and III integrated genes were not detected. ESBLs-producing genotyping-positive bacteria were detected with more than 50% of type I integrated genes. It was concluded that type I integrated genes in ESBLs-producing E. coli isolated from elderly patients carried resistance genes such as CTX-M-9 and CTX-M-2 aggravating multi-drug resistance in bacteria.
本实验旨在通过分析老年患者血流感染中产 ESBLs 大肠埃希菌的耐药特征及整合基因分布，为临床血流感染的治疗提供依据。为此，收集 2016 年 1 月至 2019 年 12 月医院老年患者血流感染标本，进行细菌鉴定和药敏试验，采用 PCR 扩增法检测 ESBLs 阳性菌株基因型及其整合子携带率，比较分析各种基因型率的特点和差异。结果共分离出 230 株大肠埃希菌，产 ESBLs 菌检出率为 37.39%；产 ESBLs 大肠埃希菌对头孢吡肟、左氧氟沙星、复方磺胺甲噁唑、替卡西林/克拉维酸耐药率较高（＞40%），对美罗培南、米诺环素、阿米卡星、庆大霉素、头孢西丁的耐药率均＜20%；老年患者血流感染中产 ESBLs 大肠埃希菌中 CTX-M-9 占 27.91%、CTX-M-2 占 17.44%、SHV 占 13.95%；Ⅰ型整合子基因检出率为 41.30%，未检出Ⅱ、Ⅲ型整合子基因；产 ESBLs 基因分型阳性菌中Ⅰ型整合子基因携带率＞50%。结论老年患者中产 ESBLs 大肠埃希菌携带 CTX-M-9、CTX-M-2 等耐药基因的Ⅰ型整合子基因，使细菌耐药性加重呈多重耐药。
