Hu Xinxin, Tao Jia, Yan Lixin, Hong Wei, Wang Wen, Wang Liru, Li Gang, Jia Wei
College of Clinical Medicine, Ningxia Medical University, Yinchuan, Ningxia, 750004, China.
Ningxia Key Laboratory of Clinical and Pathogenic Microbiology, General Hospital of Ningxia Medical University, Yinchua, China.
BMC Infect Dis. 2025 Feb 28;25(1):293. doi: 10.1186/s12879-025-10658-3.
To analyse the antibiotic resistance, resistance genes and clonal relationship of Escherichia coli in bloodstream infections in Ningxia from 2022 to 2023.
We retrospectively analyzed the antibiotic susceptibilities of 257 isolates. PCR was used to detect bla, bla, bla, qnrS, qnrA, qnrB, oqxA, qepA, gyrA, gyrB, parC, and parE, and the clonal relationship through multilocus sequence typing (MLST).
One hundred and twenty-nine of 257 patients were male (50.2%). The 257 E. coli isolates were mainly obtained from the Emergency, Hepatobiliary Surgery, and Haematology Departments, accounting for 56.6%, 7.3%, and 6.2%, respectively. There is no significant difference in sex and genes between the two groups over and under 60 years old (P > 0.05), but there is a significant difference in ST between them(P<0.05). The antimicrobial susceptibility testing showed that the 257 isolates had the highest rates of resistance to ampicillin (82.8%), followed by cefazolin (71.6%), and all isolates were susceptible to tigecycline. Based on the antibiotic susceptibility results for ceftriaxone, we tested 126 isolates of E. coli for extended-spectrum beta-lactamase (ESBL) resistance genes. As a result, bla was detected in 76 isolates (60.32%), bla in 26 isolates (20.63%), and bla in 38 isolates (30.16%). Based on the ciprofloxacin and levofloxacin antibiotic susceptibility results, we tested for quinolone resistance genes in 148 isolates, revealing 66 isolates of aac(6')-Ib-cr (44.60%), 3 isolates of oqxA (2.02%), 32 isolates of qnrS (21.62%), and 2 isolates of qepA (1.35%). We did not detect qnrA or qnrB. The detection rates of gyrA, gyrB, parC, and parE were 98%, 42.6%, 91.2%, and 87.8%, respectively and the main amino acid mutations were Ser83 to Leu, Asp87 to Asn(75.2%), Leu417 to Ser, Ser418 to Leu (6.3%), Ser80 to Ile (65.2%), and Ser458 to Ala (21.5%), respectively. MLST revealed that the most common sequence types (STs) were ST69 (12.5%), ST131 (8.2%), and ST1193 (7.8%).
In our hospital, E. coli was resistant to most commonly used antibiotics, and cefoperazone/sulbactam, cefotetan, amikacin, and tigecycline were empirically selected for the treatment of bloodstream infections. The predominant ESBL genotype in our hospital was bla and the major quinolone resistance gene was aac(6')-Ib-cr. Clonal relationship analysis revealed genetic diversity among the isolates.
分析2022年至2023年宁夏血流感染大肠埃希菌的耐药性、耐药基因及克隆关系。
回顾性分析257株分离菌的药敏情况。采用聚合酶链反应（PCR）检测bla、bla、bla、qnrS、qnrA、qnrB、oqxA、qepA、gyrA、gyrB、parC和parE，并通过多位点序列分型（MLST）分析克隆关系。
257例患者中129例为男性（50.2%）。257株大肠埃希菌主要分离自急诊科、肝胆外科和血液科，分别占56.6%、7.3%和6.2%。60岁及以上和60岁以下两组在性别和基因方面无显著差异（P＞0.05），但ST型别存在显著差异（P＜0.05）。药敏试验显示，257株分离菌对氨苄西林耐药率最高（82.8%），其次为头孢唑林（71.6%），所有分离菌对替加环素敏感。根据头孢曲松药敏结果，对126株大肠埃希菌检测超广谱β-内酰胺酶（ESBL）耐药基因。结果显示，76株（60.32%）检测到bla，26株（20.63%）检测到bla，38株（30.16%）检测到bla。根据环丙沙星和左氧氟沙星药敏结果，对148株分离菌检测喹诺酮耐药基因，发现66株（44.60%）为aac(6')-Ib-cr，3株（2.02%）为oqxA，32株（21.62%）为qnrS，2株（1.35%）为qepA。未检测到qnrA和qnrB。gyrA、gyrB、parC和parE的检测率分别为98%、42.6%、91.2%和87.8%，主要氨基酸突变分别为Ser83突变为Leu、Asp87突变为Asn（75.2%）、Leu417突变为Ser、Ser418突变为Leu（6.3%）、Ser80突变为Ile（65.2%）、Ser458突变为Ala（21.5%）。MLST显示最常见的序列型别（ST）为ST69（12.5%）、ST131（8.2%）和ST1193（7.8%）。
我院大肠埃希菌对常用抗生素耐药，经验性选用头孢哌酮/舒巴坦、头孢替坦、阿米卡星和替加环素治疗血流感染。我院主要的ESBL基因型为bla，主要的喹诺酮耐药基因是aac(6')-Ib-cr。克隆关系分析显示分离株间存在基因多样性。
