Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKp) has been increasingly reported and is now recognized as a public health concern. The aim of this study was to investigate the molecular epidemiology of CR-hvKp strains that were isolated from an Iranian hospital. A total of 74 non-duplicated carbapenem-resistant K. pneumoniae (CR-Kp) were collected from patients’ clinical or surveillance cultures. Resistance/virulence genes were identified by PCR and sequencing. String test, capsular genotyping, conjugation assays, PCR-based replicon typing, pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and were performed. All 74 CR-Kp isolates were carbapenemase producers, which co-carried multiple resistance genes such as bla_CTX-M-15, bla_TEM-1, bla_SHV-type, qnrB1, and qnrS1. The most common carbapenemase gene was bla_OXA-48 (67/74 90.5%), followed by bla_NDM-1 (18/74 24.3%), and bla_NDM-7 (3/74 4%). The bla_OXA-48 and bla_NDM-1 were found on IncL/M and IncFII conjugative plasmids, respectively. Of 74 CR-Kp isolates, 49 were positive for string test. Capsular genotyping revealed that 34 and 10 CR-Kp strains belonged to the K1 and K2 serotypes, respectively. rmpA was the most prevalent virulence gene detected in 64.8% of the isolates. Fifty two strains were identified as CR-hvKp. PFGE typing showed 5 different clusters with two major clusters B (39 isolates, 52.7%) associated with sequence type 11 (ST11), and A (21 isolates, 28.4%) associated with ST893. Furthermore, ST147, ST392, and ST15 carbapenemase producers have also been sporadically identified. One isolate belonging to ST11 was resistant to colistin and were negative for mcr-1-2-3 genes. Insertional inactivation of mgrB due to IS elements was observed in the colistin-resistant isolate. Our findings suggest that ST11 CR-hvKP strain has a clonal distribution in our hospital. Therefore, immediate implementation of infection-control measures may be the best way to prevent the spread of these clones.

耐碳青霉烯类高毒力肺炎克雷伯菌(CR-hvKp) 的报道越来越多，现在被认为是一个公共卫生问题。本研究的目的是调查从伊朗医院分离的 CR-hvKp 菌株的分子流行病学。从患者的临床或监测培养物中收集了总共 74 个非重复的耐碳青霉烯类肺炎克雷伯菌(CR-Kp)。通过PCR和测序鉴定抗性/毒力基因。进行了字符串测试、荚膜基因分型、缀合测定、基于 PCR 的复制子分型、脉冲场凝胶电泳 (PFGE)、多位点序列分型 (MLST)。所有 74 个 CR-Kp 分离株都是碳青霉烯酶生产者，它们共同携带多种抗性基因，如bla_CTX-M-15、bla _TEM-1、bla _{SHV 型}、qnrB1和qnrS1。最常见的碳青霉烯酶基因是bla _OXA-48（67/74 90.5%），其次是bla _NDM-1（18/74 24.3%）和bla _NDM-7（3/74 4%）。bla _OXA-48和bla _NDM-1分别在 IncL/M 和 IncFII 结合质粒上发现。74株CR-Kp分离株中，49株串试验阳性。荚膜基因分型显示 34 和 10 株 CR-Kp 分别属于 K1 和 K2 血清型。rmpA是在 64.8% 的分离物中检测到的最普遍的毒力基因。52 株被鉴定为 CR-hvKp。PFGE 分型显示 5 个不同的簇，其中两个主要簇 B（39 个分离株，52.7%）与序列类型 11（ST11）相关，A（21 个分离株，28.4%）与 ST893 相关。此外，还偶尔发现了 ST147、ST392 和 ST15 碳青霉烯酶生产者。属于 ST11 的一种分离物对粘菌素具有抗性，并且对mcr-1-2-3基因呈阴性。mgrB的插入失活由于 IS 元素在多粘菌素抗性分离物中观察到。我们的研究结果表明，ST11 CR-hvKP 菌株在我院具有克隆分布。因此，立即实施感染控制措施可能是防止这些克隆传播的最佳方式。