Fournier Claudine, Poirel Laurent, Despont Sarah, Kessler Julie, Nordmann Patrice
Medical and Molecular Microbiology Unit, Faculty of Science and Medicine, University of Fribourg, 1700 Fribourg, Switzerland.
INSERM European Unit (IAME, France), University of Fribourg, 1700 Fribourg, Switzerland.
Microorganisms. 2022 Mar 14;10(3):615. doi: 10.3390/microorganisms10030615.
Aminoglycosides (AGs) in combination with β-lactams play an important role in antimicrobial therapy in severe infections. Pan-resistance to clinically relevant AGs increasingly arises from the production of 16S rRNA methylases (RMTases) that are mostly encoded by plasmids in Gram-negative bacteria. The recent emergence and spread of isolates encoding RMTases is worrisome, considering that they often co-produce extended-spectrum β-lactamases (ESBLs) or carbapenemases. Our study aimed to retrospectively analyze and characterize the association of carbapenem- and aminoglycoside-resistant clinical isolates in Switzerland during a 3.5-year period between January 2017 and June 2020. A total of 103 pan-aminoglycoside- and carbapenem-resistant clinical isolates were recovered at the NARA (Swiss National Reference Center for Emerging Antibiotic Resistance) during the 2017-2020 period. Carbapenemase and RMTase determinants were identified by PCR and sequencing. The characterization of plasmids bearing resistance determinants was performed by a mating-out assay followed by PCR-based replicon typing (PBRT). Clonality of the isolates was investigated by multilocus sequence typing (MLST). Over the 991 collected at the NARA during this period, 103 (10.4%) of them were resistant to both carbapenems and all aminoglycosides. Among these 103 isolates, 35 isolates produced NDM-like carbapenemases, followed by OXA-48-like ( = 23), KPC-like ( = 21), or no carbapenemase ( = 13), OXA-48-like and NDM-like co-production ( = 7), and VIM-like enzymes ( = 4). The RMTases ArmA, RmtB, RmtC, RmtF, RmtG, and RmtB + RmtF were identified among 51.4%, 13.6%, 4.9%, 24.3%, 1%, and 1%, respectively. Plasmid co-localization of the carbapenemase and the RMTase encoding genes was found among ca. 20% of the isolates. A high diversity was identified in terms of the nature of associations between RMTase and carbapenemase-encoding genes, of incompatibility groups of the corresponding plasmids, and of strain genetic backgrounds, highlighting heterogeneous importations rather than clonal dissemination.
氨基糖苷类（AGs）与β-内酰胺类联合使用在严重感染的抗菌治疗中发挥着重要作用。临床上对相关AGs的全耐药性越来越多地源于16S rRNA甲基化酶（RMTases）的产生，这些酶大多由革兰氏阴性菌中的质粒编码。鉴于编码RMTases的分离株经常同时产生超广谱β-内酰胺酶（ESBLs）或碳青霉烯酶，其最近的出现和传播令人担忧。我们的研究旨在回顾性分析和描述2017年1月至2020年6月这3.5年期间瑞士碳青霉烯类和氨基糖苷类耐药临床分离株之间的关联。在2017 - 2020年期间，瑞士国家新兴抗生素耐药性参考中心（NARA）共收集到103株对所有氨基糖苷类和碳青霉烯类均耐药的临床分离株。通过PCR和测序鉴定碳青霉烯酶和RMTase决定簇。通过接合转移试验，随后进行基于PCR的复制子分型（PBRT），对携带耐药决定簇的质粒进行特征分析。通过多位点序列分型（MLST）研究分离株的克隆性。在此期间，NARA收集的991株分离株中，有103株（10.4%）对碳青霉烯类和所有氨基糖苷类均耐药。在这103株分离株中，35株产生NDM样碳青霉烯酶，其次是OXA - 48样（ = 23）、KPC样（ = 21）或不产生碳青霉烯酶（ = 13）、OXA - 48样和NDM样共同产生（ = 7）以及VIM样酶（ = 4）。分别在51.4%、13.6%、4.9%、24.3%、1%和1%的分离株中鉴定出RMTases ArmA、RmtB、RmtC、RmtF、RmtG以及RmtB + RmtF。在约20%的分离株中发现了碳青霉烯酶和RMTase编码基因的质粒共定位。在RMTase和碳青霉烯酶编码基因之间的关联性质、相应质粒的不相容群以及菌株遗传背景方面发现了高度多样性，突出了异源导入而非克隆传播。
