Research Center for Gastroenterology and Liver Disease, Shahid Beheshti University, Medical Sciences, Tehran, Iran.
J Antimicrob Chemother. 2012 May;67(5):1128-33. doi: 10.1093/jac/dks023. Epub 2012 Feb 17.
In this study, we wanted to assess the level of antimicrobial resistance, the presence of genes encoding resistance to cephalosporins and plasmid-mediated quinolone resistance (PMQR), and genetic relatedness among Shigella isolates obtained from Iranian patients.
A total of 44 Shigella isolates were collected from Iranian patients admitted to Milad Hospital, Tehran, Iran, during 2008-10. Of these, 37 were serotyped and characterized by MIC determination. A subset of eight suspected extended-spectrum β-lactamase (ESBL) producers (six Shigella sonnei phase II and two Shigella flexneri type 1b) were examined for the presence of genes encoding cephalosporin resistance. The presence of PMQR was assessed in one S. flexneri isolate exhibiting low-level resistance to ciprofloxacin and susceptibility to nalidixic acid. PFGE was performed on 25 S. sonnei phase II isolates.
Of the isolates, 25 (68%) were S. sonnei phase II, with 5 (14%) S. flexneri, 5 (14%) Shigella dysenteriae type 2, and 2 (5%) Shigella boydii type 2. Resistance to at least threeclasses of antimicrobials was detected in all species. The presence of bla(CTX-M-15) and the AmpC β-lactamase producer bla(CMY-2) was confirmed in five and one S. sonnei phase II isolates, respectively. One of the two S. flexneri type 1b that contained bla(CTX-M-15) also harboured a qnrS1 gene. PFGE identified sevenPFGE profiles; the main cluster included 15 of the strains, suggesting low genetic diversity between isolates or the presence of an endemic clone in Iran.
This is the first known description of ESBL-producing and AmpC β-lactamase-producing Shigella and of PMQR Shigella in Iran. The emergence of CTX-15, CMY-2 and qnrS1 genes may compromise the treatment of shigellosis. Strategies to minimize the spread of ESBL-producing and AmpC-β-lactamase-producing Shigella should be implemented.
本研究旨在评估从伊朗患者中分离的志贺菌的抗生素耐药水平、头孢菌素耐药基因和质粒介导的喹诺酮耐药（PMQR）的存在情况，以及遗传相关性。
2008 年至 2010 年，从伊朗德黑兰 Milad 医院的住院患者中收集了 44 株志贺菌分离株。其中 37 株进行了血清型鉴定，并通过 MIC 测定进行了特征描述。对 8 株疑似产超广谱β-内酰胺酶（ESBL）的菌株（6 株志贺氏菌 2 期和 2 株福氏志贺菌 1b 型）进行了头孢菌素耐药基因检测。对 1 株对环丙沙星低水平耐药但对萘啶酸敏感的福氏志贺菌进行了 PMQR 检测。对 25 株志贺氏菌 2 期进行了 PFGE 分析。
分离株中 25 株（68%）为志贺氏菌 2 期，5 株（14%）为福氏志贺菌，5 株（14%）为痢疾志贺菌 2 型，2 株（5%）为鲍氏志贺菌 2 型。所有志贺菌均对至少三类抗生素耐药。在 5 株志贺氏菌 2 期分离株中证实了 bla(CTX-M-15)的存在和 bla(CMY-2)的 AmpC β-内酰胺酶产生菌，分别在 1 株福氏志贺菌 1b 中检测到 bla(CTX-M-15)和 qnrS1 基因。PFGE 确定了 7 种 PFGE 图谱；主要聚类包括 15 株菌株，表明分离株之间遗传多样性较低或伊朗存在地方性克隆。
这是伊朗首例报道的产 ESBL 和 AmpC β-内酰胺酶的志贺菌和产 PMQR 的志贺菌。CTX-15、CMY-2 和 qnrS1 基因的出现可能会影响志贺菌病的治疗。应实施策略以最大程度减少产 ESBL 和 AmpC-β-内酰胺酶的志贺菌的传播。
