Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.
Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Shanghai, China.
Microbiol Spectr. 2023 Jun 15;11(3):e0386322. doi: 10.1128/spectrum.03863-22. Epub 2023 Apr 27.
OXA-232 carbapenemase is becoming a threat in China due to its high prevalence, mortality, and limited treatment options. However, little information is available on the impact of OXA-232-producing Klebsiella pneumoniae in China. This study aims to characterize the clonal relationships, the genetic mechanisms of resistance, and the virulence of OXA-232-producing K. pneumoniae isolates in China. We collected 81 OXA-232-producing K. pneumoniae clinical isolates from 2017 to 2021. Antimicrobial susceptibility testing was performed using the broth microdilution method. Capsular types, multilocus sequence types, virulence genes, antimicrobial resistance (AMR) determinants, plasmid replicon types, and single-nucleotide polymorphism (SNP) phylogeny were inferred from whole-genome sequences. OXA-232-producing K. pneumoniae strains were resistant to most antimicrobial agents. These isolates showed partial differences in susceptibility to carbapenems: all strains were resistant to ertapenem, while the resistance rates to imipenem and meropenem were 67.9% and 97.5%, respectively. Sequencing and capsular diversity analysis of the 81 K. pneumoniae isolates revealed 3 sequence types (ST15, ST231, and one novel ST [ST-V]), 2 K-locus types (KL112 and KL51), and 2 O-locus types (O2V1 and O2V2). The predominant plasmid replicon types associated with the OXA-232 and genes were ColKP3 (100%) and IncFIB-like (100%). Our study summarized the genetic characteristics of OXA-232-producing K. pneumoniae circulating in China. The results demonstrate the practical applicability of genomic surveillance and its utility in providing methods to prevent transmission. It alerts us to the urgent need for longitudinal surveillance of these transmissible lineages. In recent years, the detection rate of carbapenem-resistant K. pneumoniae has increased and represents a major threat to clinical anti-infective therapy. Compared with KPC-type carbapenemases and NDM-type metallo-β-lactamases, OXA-48 family carbapenemases are another important resistance mechanism mediating bacterial resistance to carbapenems. In this study, we investigated the molecular characteristics of OXA-232 carbapenemase-producing K. pneumoniae isolated from several hospitals to clarify the epidemiological dissemination characteristics of such drug-resistant strains in China.
产 OXA-232 碳青霉烯酶的肺炎克雷伯菌由于其高流行率、高死亡率和有限的治疗选择，在中国已成为一种威胁。然而，关于中国产 OXA-232 肺炎克雷伯菌的影响的信息很少。本研究旨在描述中国产 OXA-232 肺炎克雷伯菌的克隆关系、耐药的遗传机制和毒力。我们收集了 2017 年至 2021 年期间的 81 株产 OXA-232 肺炎克雷伯菌临床分离株。采用肉汤微量稀释法进行抗菌药物敏感性试验。从全基因组序列中推断出荚膜型、多位点序列型、毒力基因、抗菌药物耐药性（AMR）决定因素、质粒复制子类型和单核苷酸多态性（SNP）系统发育。产 OXA-232 肺炎克雷伯菌对大多数抗菌药物均耐药。这些分离株对碳青霉烯类药物的敏感性存在部分差异：所有菌株均对厄他培南耐药，而对亚胺培南和美罗培南的耐药率分别为 67.9%和 97.5%。对 81 株肺炎克雷伯菌分离株的测序和荚膜多样性分析显示，存在 3 种序列型（ST15、ST231 和一种新型 ST[ST-V]）、2 种 K 型（KL112 和 KL51）和 2 种 O 型（O2V1 和 O2V2）。与 OXA-232 和 基因相关的主要质粒复制子类型是 ColKP3（100%）和 IncFIB 样（100%）。本研究总结了中国流行的产 OXA-232 肺炎克雷伯菌的遗传特征。结果表明，基因组监测具有实际应用价值，并为预防传播提供了方法。这提醒我们迫切需要对这些可传播谱系进行纵向监测。近年来，碳青霉烯类耐药肺炎克雷伯菌的检出率不断上升，对临床抗感染治疗构成重大威胁。与 KPC 型碳青霉烯酶和 NDM 型金属β-内酰胺酶相比，OXA-48 家族碳青霉烯酶是另一种介导细菌对碳青霉烯类药物耐药的重要耐药机制。本研究调查了从多家医院分离的产 OXA-232 碳青霉烯酶肺炎克雷伯菌的分子特征，以阐明此类耐药菌株在中国的流行病学传播特征。
