耐碳青霉烯类肺炎克雷伯菌(CRKP)的迅速出现和新抗生素的开发相对有限,对公众健康构成了重大威胁。氨基糖苷是与β-内酰胺药物联合治疗可有效降低死亡率的重要选择。然而,在这项研究中,我们观察到两种多重耐药(MDR)肺炎克雷伯菌,命名为1632和1864,对碳青霉烯类和氨基糖苷类都表现出高度耐药.通过全基因组测序(WGS),rmtB的异常共现,arma,和blaKPC-2基因,与两个关键的抗性质粒相关联,在两个分离株中观察到。值得注意的是,我们还发现arma抗性基因和毒力因子iuc操纵子共同出现在肺炎克雷伯菌1864的同一质粒上。详细的比较遗传分析表明,所有这些质粒都被认为是可移动的质粒,因为它们都带有基本的orit站点。结合实验结果表明,两个分离株的armA阳性质粒均能有效自转移至大肠杆菌J53,尤其是,p1864-1质粒,可以将高毒力和多药耐药表型共同转移给其他分离株。此外,在重要的抗性基因周围还发现了多个插入序列(ISs)和转座子(Tns),这甚至可以形成一个大的抗生素抗性岛(ARI),并可以刺激抗性决定簇的动员。总的来说,我们报道了arma质粒的罕见共存,rmtB-blaKPC-2质粒,甚至在肺炎克雷伯菌分离物中编码iuc毒力操纵子的质粒,这大大增加了这些高风险表型的传播,这是非常令人担忧的。重要性产生碳青霉烯酶的肺炎克雷伯菌已成为抗菌化疗的巨大挑战,而氨基糖苷类与它们联合治疗可有效降低死亡率。不幸的是,我们从患者的血液样本中分离出两种肺炎克雷伯菌,这些患者不仅对碳青霉烯类和氨基糖苷类表现出高水平的耐药性,而且还表现出rmtB的异常共现,arma,和blaKPC-2基因.这些元件都位于移动质粒上,两侧是多态移动遗传元件(MGEs)。最糟糕的是,我们还鉴定了一种共轭毒力MDR质粒,共同拥有多个抗性决定因素,和iuc操纵子,证实可以将这种高风险表型转移到其他分离株。这种共轭毒力质粒的出现可以促进毒力编码元件在革兰氏阴性病原体中的快速传播。这种罕见的rmtB共存,arma,肺炎克雷伯菌blaKPC-2和iuc毒力操纵子编码质粒,给临床治疗带来了巨大的威胁。有必要进行未来的研究以评估此类分离株的患病率。
The rapid emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) and the comparatively limited development of new antibiotics pose a major threat to public health. Aminoglycosides are important options that can lower the mortality rate effectively in combination therapy with β-lactam agents. However, in this study, we observed two multidrug-resistant (MDR) K. pneumoniae named 1632 and 1864 that exhibited high-level resistance to both carbapenems and aminoglycosides. Through whole-genome sequencing (WGS), the unusual co-occurrence of rmtB,
armA, and blaKPC-2 genes, associating with two key resistance plasmids, was observed in two isolates. Notably, we also found that the
armA resistance gene and virulence factor iuc operon co-occurred on the same plasmid in K. pneumoniae 1864. Detailed comparative genetic analysis showed that all these plasmids were recognized as mobilizable plasmids, as they all carry the essential oriT site. Results of conjugation assay indicated that
armA-positive plasmids in two isolates could self-transfer to Escherichia coli J53 effectively, especially, the p1864-1 plasmid, which could cotransfer hypervirulent and multidrug-resistant phenotypes to other isolates. Moreover, multiple insertion sequences (ISs) and transposons (Tns) were also found surrounding the vital resistant genes, which could even form a large antibiotic resistance island (ARI) and could stimulate mobilization of resistant determinants. Overall, we report the uncommon coexistence of
armA plasmid, rmtB-blaKPC-2 plasmid, and even iuc virulence operon-encoding plasmid in K. pneumoniae isolates, which greatly increased the spread of these high-risk phenotypes and which are of great concern. IMPORTANCE Carbapenemase-producing Klebsiella pneumoniae have become a great challenge for antimicrobial chemotherapy, while aminoglycosides can lower the mortality rate effectively in combination therapy with them. Unfortunately, we isolated two K. pneumoniae from blood sample of patients that not only exhibited high-level resistance to carbapenems and aminoglycosides but also showed the unusual co-occurrence of the rmtB,
armA, and blaKPC-2 genes. These elements were all located on mobile plasmids and flanked by polymorphic mobile genetic elements (MGEs). What\'s worse most, we also identified a conjugative virulent MDR plasmid, coharboring multiple resistant determinants, and iuc operon, which was confirmed could transfer such high-risk phenotype to other isolates. The emergence of such conjugative virulence plasmids may promote the rapid dissemination of virulence-encoding elements among Gram-negative pathogens. This uncommon coexistence of rmtB, armA, blaKPC-2, and iuc virulence operon-encoding plasmids in K. pneumoniae, presents a huge threat to clinical treatment. Future studies are necessary to evaluate the prevalence of such isolates.