Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil.
Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil; Universidade Federal de Roraima, Boa Vista, Roraima, Brazil.
J Glob Antimicrob Resist. 2020 Mar;20:18-21. doi: 10.1016/j.jgar.2019.06.014. Epub 2019 Jun 25.
The extensively drug-resistant (XDR) Acinetobacter baumannii international clone VI (IC-6) has been identified worldwide since 2006. This study reports the emergence of IC-6 in the Brazilian Amazon region and reveals the particular genomic features considering its mobilome and resistome.
A total of 32 carbapenem-resistant A. baumannii strains recovered from Boa Vista city (Roraima, Brazil) in 2016 were characterised by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The whole genome sequences of the Brazilian IC-6 strains were obtained. The mobilome and resistome were assessed by in silico analyses.
PFGE and MLST demonstrated that the 32 A. baumannii strains belonged to four clones. One XDR clone corresponded to the high-risk pandemic IC-6 lineage from ST944/78. The IC-6 resistome was composed of aadA5, aac(3'')-IIa, aph(3')-Ia, armA, aadB, msrE, bla, IS15DIV-bla-IS15DIV, bla, ISAba1-bla, bla, qacEΔ1 and sul1. Mobilome prediction revealed that bla was embedded in a 15.5-kb plasmid and that it was flanked by putative XerC/D-binding sites, possibly involved in bla mobilisation. Several resistance genes were in a 48-kb multidrug resistance genomic island inserted in the chromosome, which also harboured genes involved in host pathogenicity and adaptive traits. Interestingly, the Brazilian strains shared the bla and bla with IC-6/ST944/78 recovered in a distinct spatiotemporal context, pointing to an epidemiological link among them.
This study highlights the importance of surveillance of XDR A. baumannii strains, even outside of densely populated cosmopolitan regions, to reveal the epidemiology of pandemic lineages, stressing their threat to public health.
广泛耐药（XDR）鲍曼不动杆菌国际克隆 VI（IC-6）自 2006 年以来在全球范围内被发现。本研究报告了 IC-6 在巴西亚马逊地区的出现，并揭示了其移动组和抗性组的特殊基因组特征。
对 2016 年从巴西罗赖马州博阿维斯塔市采集的 32 株碳青霉烯类耐药鲍曼不动杆菌进行脉冲场凝胶电泳（PFGE）和多位点序列分型（MLST）分析。获得了巴西 IC-6 菌株的全基因组序列。通过计算机分析评估了移动组和抗性组。
PFGE 和 MLST 表明，32 株鲍曼不动杆菌菌株属于四个克隆群。一个 XDR 克隆与来自 ST944/78 的高风险流行 IC-6 谱系相对应。IC-6 抗性组由 aadA5、aac(3'')-IIa、aph(3')-Ia、armA、aadB、msrE、bla、IS15DIV-bla-IS15DIV、bla、ISAba1-bla、bla、qacEΔ1 和 sul1 组成。移动组预测表明，bla 嵌入在一个 15.5kb 的质粒中，其两侧可能是参与 bla 移动的 XerC/D 结合位点。几个抗性基因位于插入染色体中的一个 48kb 的多药耐药基因组岛中，该基因组岛还包含与宿主致病性和适应特性相关的基因。有趣的是，巴西分离株与在不同时空背景下分离的 IC-6/ST944/78 株共享 bla 和 bla，表明它们之间存在流行病学联系。
本研究强调了即使在人口密度较低的大都市地区之外，对 XDR 鲍曼不动杆菌菌株进行监测的重要性，以揭示流行谱系的流行病学，并强调其对公共卫生的威胁。
