Repeated local emergence of carbapenem-resistant Acinetobacter baumannii in a single hospital ward.
Repeated local emergence of carbapenem-resistant Acinetobacter baumannii in a single hospital ward.
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DOI：
10.1099/mgen.0.000050
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发表时间：
2016-03
影响因子：
3.9
通讯作者：
Holt KE
中科院分区：
文献类型：
--
作者：
Schultz MB;Pham Thanh D;Tran Do Hoan N;Wick RR;Ingle DJ;Hawkey J;Edwards DJ;Kenyon JJ;Phu Huong Lan N;Campbell JI;Thwaites G;Thi Khanh Nhu N;Hall RM;Fournier-Level A;Baker S;Holt KE
我们最近报告了一个急剧增加的流行率碳青霉烯类耐药鲍曼不动杆菌感染的重症监护病房（ICU）的越南医院。这种激增与一个特定的oxa 23阳性克隆，确定了多位点VNTR分析。在这里，我们使用全基因组序列分析来剖析碳青霉烯类耐药A。2009-2012年期间在ICU中引起呼吸机相关性肺炎（VAP）的鲍曼不动杆菌。为了提供历史背景并区分微进化和菌株引入，我们将这些基因组与A. 2003-2007年期间从同一ICU收集的鲍曼不动杆菌无症状携带和VAP分离株。我们发现了多年来共同传播的不同血统。碳青霉烯类抗生素耐药与多个谱系中oxa 23、oxa 40、oxa 58和ndm 1基因的存在相关。大多数耐药分离株是oxa 23阳性的全球克隆GC 2;精细规模的PCR基因组分析显示，ICU内有5个不同的GC 2亚系，它们通过oxa 23转座子的独立染色体插入在本地进化。耐碳青霉烯类抗生素A.鲍曼不动杆菌与碳青霉烯酶基因的转座子介导的传递有关，而不是携带碳青霉烯酶的质粒的克隆扩增或扩散。此外，我们发现了同源重组的证据，在当地GC 2人群中创造多样性，包括几个事件，导致更换胶囊基因座。我们在A.鲍曼不动杆菌在同一病区分离，这表明多样化在很大程度上是通过重组和共享遗传物质内的本地A。鲍曼不动杆菌种群。
We recently reported a dramatic increase in the prevalence of carbapenem-resistant Acinetobacter baumannii infections in the intensive care unit (ICU) of a Vietnamese hospital. This upsurge was associated with a specific oxa23-positive clone that was identified by multilocus VNTR analysis. Here, we used whole-genome sequence analysis to dissect the emergence of carbapenem-resistant A. baumannii causing ventilator-associated pneumonia (VAP) in the ICU during 2009–2012. To provide historical context and distinguish microevolution from strain introduction, we compared these genomes with those of A. baumannii asymptomatic carriage and VAP isolates from this same ICU collected during 2003–2007. We identified diverse lineages co-circulating over many years. Carbapenem resistance was associated with the presence of oxa23, oxa40, oxa58 and ndm1 genes in multiple lineages. The majority of resistant isolates were oxa23-positive global clone GC2; fine-scale phylogenomic analysis revealed five distinct GC2 sublineages within the ICU that had evolved locally via independent chromosomal insertions of oxa23 transposons. The increase in infections caused by carbapenem-resistant A. baumannii was associated with transposon-mediated transmission of a carbapenemase gene, rather than clonal expansion or spread of a carbapenemase-harbouring plasmid. Additionally, we found evidence of homologous recombination creating diversity within the local GC2 population, including several events resulting in replacement of the capsule locus. We identified likely donors of the imported capsule locus sequences amongst the A. baumannii isolated on the same ward, suggesting that diversification was largely facilitated via reassortment and sharing of genetic material within the localized A. baumannii population.