Introduction. Carbapenem-resistant enterobacterales (CRE) are listed among the most urgent antibiotic resistance threats. Hypothesis. Previous studies on the mechanisms of CRE in Kuwait have focused on carbapenemases. There have been no studies on non-carbapenemase-producing CRE in Kuwait. Aim/Gap Statement. The aim of this study was to investigate the genetic characteristics of non-carbapenemase-producing carbapenem-resistant enterobacterales (NCPE) isolates using whole-genome sequencing (WGS). Methodology. Fourteen confirmed NCPE isolates that were negative for genes encoding carbapenemase production by polymerase chain reaction (PCR) assays using rectal swabs from intensive care unit patients were characterized using phenotypic, PCR and WGS methods. Susceptibility testing was performed via Etest and clonality via multi-locus sequence typing (MLST). Results. All of the isolates were resistant to ertapenem; 78.6 % were resistant to imipenem, meropenem and trimethoprim–sulfamethoxazole. Resistance to the other antibiotics was variable, ranging from 28.5 (colistin) through 50 (tigecycline) and 64.3 (amikacin) up to 85.7 % against both amoxicillin–clavulanic acid and ciprofloxacin. WGS detected several resistance genes mediating the production of β-lactamases, genes encoding an outer-membrane porin permeability mutation resulting in reduced susceptibility to β-lactams, including carbapenems, and genes for multidrug-resistant (MDR) efflux pumps. The isolates also possessed global activator protein MarA, which mediated reduced permeability to β-lactams. The existence of β-lactamase genes, overexpression of MDR efflux pumps and reduced permeability mediated by the porin genes were responsible for carbapenem resistance. Conclusions. This finding reflects the superior detection capabilities offered by WGS analysis, which can be used to complement traditional methods and overcome their limited resolution in clinical settings.

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通过全基因组测序从科威特ICU患者获得的碳青霉烯酶阴性耐碳青霉烯肠杆菌直肠分离株的分子特征

介绍。耐碳青霉烯肠杆菌 (CRE) 被列为最紧迫的抗生素耐药性威胁之一。假设。先前关于科威特 CRE 机制的研究主要集中在碳青霉烯酶上。科威特没有关于不产生碳青霉烯酶的 CRE 的研究。目标/差距声明。本研究的目的是使用全基因组测序 (WGS) 调查不产生碳青霉烯酶的耐碳青霉烯肠杆菌 (NCPE) 分离株的遗传特征。方法。使用表型、PCR 和 WGS 方法对 14 株经证实的 NCPE 分离株进行了表征，这些分离株通过聚合酶链反应 (PCR) 测定法使用来自重症监护病房患者的直肠拭子对编码碳青霉烯酶的基因呈阴性。敏感性测试通过 Etest 进行，克隆性通过多位点序列分型 (MLST) 进行。结果。所有分离株均对厄他培南耐药；78.6% 对亚胺培南、美罗培南和甲氧苄啶-磺胺甲恶唑耐药。对其他抗生素的耐药性是可变的，从 28.5（粘菌素）到 50（替加环素）和 64.3（阿米卡星），对阿莫西林-克拉维酸和环丙沙星的耐药率高达 85.7%。WGS 检测到几种介导 β-内酰胺酶产生的抗性基因，编码外膜孔蛋白渗透性突变的基因导致对 β-内酰胺类药物（包括碳青霉烯类）的易感性降低，以及耐多药 (MDR) 外排泵基因。这些分离物还具有全局激活蛋白 MarA，它介导了对 β-内酰胺的渗透性降低。β-内酰胺酶基因的存在，结论。这一发现反映了 WGS 分析提供的卓越检测能力，可用于补充传统方法并克服其在临床环境中的有限分辨率。