Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Ciudad Autónoma de Buenos Aires, Argentina; CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Ciudad Autónoma de Buenos Aires, Argentina.
University of Genoa, Department of Surgical Sciences and Integrated Diagnostics (DISC), Genoa, Italy.
J Glob Antimicrob Resist. 2024 Jun;37:176-178. doi: 10.1016/j.jgar.2024.03.017. Epub 2024 Apr 5.
To describe at genomic level nine carbapenemase-producing Klebsiella pneumoniae ST307 (Kp-ST307) clinical isolates recovered in Buenos Aires during 2017 to 2021, investigating their resistome, virulome, and phylogeny.
Antimicrobial susceptibility was determined according to Clinical and Laboratory Standards Intitute (CLSI). Genomic DNA was sequenced by Illumina MiSeq and analysed using SPAdes, PROKKA, and Kleborate. Phylogeny of 355 randomly selected Kp-ST307 genomes and those from nine local isolates was inferred by a maximum-likelihood approach. The tree was visualized using Microreact.
Besides resistance to ß-lactams and fluoroquinolones, six out of nine Kp-ST307 were also resistant to ceftazidime/avibactam (CZA). This difficult-to-treat resvistance phenotype was mediated by bla and GyrA-83I/ParC-80I mutations in addition to carbapenemase coding genes. Among CZA susceptible isolates, two of them harboured bla while the other harboured bla+bla Regarding CZA-resistant isolates, three harboured bla+bla+bla, two carried bla+bla+bla, and bla+bla were detected in the remaining isolate. Furthermore, five colistin-resistant isolates presented a nonsense mutation in mgrB. Global Kp-ST307 isolates were distributed in two deep-branching lineages while local isolates were set in the main clade of the phylogenetic tree. The five isolates from the same hospital, harbouring bla or bla+bla+bla, clustered in a monophyletic subclade with Italian isolates. Also, an isolate harbouring bla+bla+bla recovered in another hospital was closed to this group. The remaining local Kp-ST307 were grouped in other subclades containing isolates of diverse geographical origin.
The inferred resistome was consistent with the resistant phenotype. Phylogeny suggested multiple introduction events in our region and a single major introduction in one hospital followed by local spread.
描述 2017 年至 2021 年期间在布宜诺斯艾利斯分离的 9 株产碳青霉烯酶肺炎克雷伯菌 ST307（Kp-ST307）的基因组水平，研究其耐药组、毒力组和系统发育。
根据临床和实验室标准协会（CLSI）进行抗菌药物敏感性测定。使用 Illumina MiSeq 对基因组 DNA 进行测序，并使用 SPAdes、PROKKA 和 Kleborate 进行分析。使用最大似然法推断 355 株随机选择的 Kp-ST307 基因组和 9 株本地分离株的系统发育。使用 Microreact 可视化树。
除了对β-内酰胺类和氟喹诺酮类药物的耐药性外，9 株 Kp-ST307 中有 6 株还对头孢他啶/阿维巴坦（CZA）耐药。这种难以治疗的耐药表型是由 bla 和 GyrA-83I/ParC-80I 突变以及碳青霉烯酶编码基因介导的。在 CZA 敏感的分离株中，有 2 株携带 bla，而另 1 株携带 bla。在 CZA 耐药的分离株中，有 3 株携带 bla+bla+bla，2 株携带 bla+bla+bla，在剩余的分离株中检测到 bla+bla。此外，5 株耐多粘菌素的分离株在 mgrB 中存在无意义突变。全球 Kp-ST307 分离株分布在两个深分支谱系中，而本地分离株则位于系统发育树的主要分支中。来自同一医院的 5 株携带 bla 或 bla+bla+bla 的分离株聚集在与意大利分离株的单系亚分支中。另一个医院分离株携带 bla+bla+bla，也与该组关系密切。其余的本地 Kp-ST307 则聚集在其他包含不同地理来源分离株的亚分支中。
推断的耐药组与耐药表型一致。系统发育提示该地区有多次引入事件，其中一次主要引入发生在一家医院，随后发生了本地传播。
