Microbiology Department, Faculty of Medicine, Semnan University of Medical Sciences, Kilometer 5 of Semnan-Damghan Highway, Semnan, 3513138111, Iran.
Student Research Committee, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran.
Eur J Clin Microbiol Infect Dis. 2017 Oct;36(10):1859-1866. doi: 10.1007/s10096-017-3021-9. Epub 2017 May 27.
Multidrug-resistant (MDR) O25b-ST131 clone of Escherichia coli is well established as a significant cause of extra-intestinal infections worldwide. However, there have been no studies about the prevalence of ST131 and its H30/H30Rx subclones from Iran. The prevalence of ST131 was 29.8% among phylogroups B2, D, and F of E.coli isolates recovered from extra-intestinal infections. Fifty-seven (90.4%) and six (9.6%) of isolates belonged to serogroups O25b and O16 respectively, and exhibited high rates of MDR (98.4% and 83.3%) and extended spectrum β-lactamase (ESBL) production (96.8% and 83.3%). The majority (56/57, 98.2%) of O25b isolates belonged to H30 lineage; of those, 24 isolates (42.8%) belonged to H30-Rx subclone. O16-ST131 isolates were H30-negative. The resistance rate values of O16-ST131subgroup were lower for fluoroquinolones/aminoglycosides and higher for carbapenems, cephalosporins, β-lactam/β-lactamase inhibitors and trimethoprim/sulfamethoxazole, as compared to O25b-ST131 isolates. Among H30 sub lineage and in comparison with non-Rx isolates, H30-Rx subclone showed higher resistance score and virulence genes (papA and papC), and was also associated with CTX-M group 1. bla carbapenemase was detected in seven O25b and one O16 isolates; of those, one O25b-ST131 isolate was carbapenem-susceptible. The ST131 isolates comprised 15 'enterobacterial repetitive intergenic consensus' (ERIC) clusters, and O16 isolates remained distributed in five groups in cluster with O25b-ST131 isolates. In conclusion, this is the first report of the presence of MDR, bla /CTX-M-positive O25b/O16-ST131 isolates in Iran. Contrary to lower prevalence of O16-ST131 subgroup, higher resistance rates to β-lactam antibiotics may indicate the importance of this subgroup in the spread of MDR E.coli isolates.
产超广谱β-内酰胺酶（ESBL）的 O25b-ST131 型大肠埃希菌克隆株是全世界肠道外感染的重要致病因子。然而，目前尚无关于伊朗流行的 ST131 及其 H30/H30Rx 亚克隆的研究。从肠道外感染分离的大肠埃希菌，其 B2、D 和 F 菌系的 ST131 流行率为 29.8%。57 株（90.4%）和 6 株（9.6%）分离株分别属于 O25b 和 O16 血清群，且表现出很高的多重耐药性（98.4%和 83.3%）和 ESBL 产生率（96.8%和 83.3%）。57 株 O25b 分离株中，大多数（56/57，98.2%）属于 H30 谱系；其中 24 株（42.8%）属于 H30-Rx 亚克隆。O16-ST131 分离株 H30 阴性。与 O25b-ST131 分离株相比，O16-ST131 亚组的氟喹诺酮/氨基糖苷类和碳青霉烯类、头孢菌素类、β-内酰胺/β-内酰胺酶抑制剂和复方磺胺甲噁唑的耐药率较低，而对碳青霉烯类的耐药率较高。在 H30 亚系中，与非-Rx 分离株相比，H30-Rx 亚克隆的耐药评分和毒力基因（papA 和 papC）更高，且与 CTX-M 组 1 相关。在 7 株 O25b 和 1 株 O16 分离株中检测到 bla 碳青霉烯酶；其中一株 O25b-ST131 分离株对碳青霉烯类敏感。ST131 分离株包括 15 个“肠杆菌重复基因间一致性”（ERIC）簇，而 O16 分离株与 O25b-ST131 分离株在簇中仍分布在五个组中。总之，这是首次在伊朗报告存在产 ESBL、bla /CTX-M 阳性的 O25b/O16-ST131 分离株。与 O16-ST131 亚组较低的流行率相反，对β-内酰胺类抗生素的更高耐药率可能表明该亚组在传播产 ESBL 大肠埃希菌分离株中的重要性。
