Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China.
J Antimicrob Chemother. 2021 Jan 1;76(1):65-69. doi: 10.1093/jac/dkaa389.
To reconstruct the evolutionary history of the clinical Acinetobacter baumannii XH1056, which lacks the Oxford scheme allele gdhB.
Susceptibility testing was performed using broth microdilution and agar dilution. The whole-genome sequence of XH1056 was determined using the Illumina and Oxford Nanopore platforms. MLST was performed using the Pasteur scheme and the Oxford scheme. Antibiotic resistance genes were identified using ABRicate.
XH1056 was resistant to all antibiotics tested, apart from colistin, tigecycline and eravacycline. MLST using the Pasteur scheme assigned XH1056 to ST256. However, XH1056 could not be typed with the Oxford MLST scheme as gdhB is not present. Comparative analyses revealed that XH1056 contains a 52 933 bp region acquired from a global clone 2 (GC2) isolate, but is otherwise closely related to the ST23 A. baumannii XH858. The acquired region in XH1056 also contains a 34 932 bp resistance island that resembles AbGRI3 and contains the armA, msrE-mphE, sul1, blaPER-1, aadA1, cmlA1, aadA2, blaCARB-2 and ere(B) resistance genes. Comparison of the XH1056 chromosome to that of GC2 isolate XH859 revealed that the island in XH1056 is in the same chromosomal region as that in XH859. As this island is not in the standard AbGRI3 position, it was named AbGRI5.
XH1056 is a hybrid isolate generated by the acquisition of a chromosomal segment from a GC2 isolate that contains a resistance island in a new location-AbGRI5. As well as generating ST256, it appears likely that a single recombination event is also responsible for the acquisition of AbGRI5 and its associated antibiotic resistance genes.
重建临床鲍曼不动杆菌 XH1056 的进化史，该菌缺乏牛津方案等位基因 gdhB。
使用肉汤微量稀释法和琼脂稀释法进行药敏试验。使用 Illumina 和 Oxford Nanopore 平台测定 XH1056 的全基因组序列。采用巴斯德方案和牛津方案进行 MLST。使用 ABRicate 鉴定抗生素耐药基因。
除多粘菌素、替加环素和依拉环素外，XH1056 对所有测试的抗生素均具有耐药性。使用巴斯德方案进行 MLST 将 XH1056 分配到 ST256。然而，由于 gdhB 不存在，XH1056 无法使用牛津 MLST 方案进行分型。比较分析表明，XH1056 含有一个来自全球克隆 2（GC2）分离株的 52933bp 区域，但在其他方面与 ST23 鲍曼不动杆菌 XH858 密切相关。XH1056 中获得的区域还包含一个 34932bp 的耐药岛，类似于 AbGRI3，含有 armA、msrE-mphE、sul1、blaPER-1、aadA1、cmlA1、aadA2、blaCARB-2 和 ere（B）耐药基因。将 XH1056 染色体与 GC2 分离株 XH859 的染色体进行比较，发现该岛位于 XH1056 与 XH859 相同的染色体区域。由于该岛不在标准 AbGRI3 位置，因此将其命名为 AbGRI5。
XH1056 是一个由 GC2 分离株获得染色体片段的杂交分离株，该片段包含一个位于新位置 AbGRI5 的耐药岛。除产生 ST256 外，单个重组事件似乎也负责 AbGRI5 及其相关抗生素耐药基因的获得。
