Centre for Research in Infectious Diseases and Biotechnology (CeRIDB), Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu, Malaysia.
School of Molecular Sciences, University of Western Australia, Perth, WA, Australia.
J Glob Antimicrob Resist. 2022 Dec;31:104-109. doi: 10.1016/j.jgar.2022.08.019. Epub 2022 Aug 29.
To analyse the genome sequences of four archival Acinetobacter nosocomialis clinical isolates (designated AC13, AC15, AC21 and AC25) obtained from Terengganu, Malaysia in 2011 to determine their genetic relatedness and basis of antimicrobial resistance.
Antimicrobial susceptibility profiles of the A. nosocomialis isolates were determined by disk diffusion. Genome sequencing was performed using the Illumina NextSeq platform.
The four A. nosocomialis isolates were cefotaxime resistant whereas three isolates (namely, AC13, AC15 and AC25) were tetracycline resistant. The carriage of the bla-encoded cephalosporinase gene is likely responsible for cefotaxime resistance in all four isolates. Phylogenetic analysis indicated that the three tetracycline-resistant isolates were closely related, with an average nucleotide identity of 99.9%, suggestive of nosocomial spread, whereas AC21 had an average nucleotide identity of 97.9% when compared to these three isolates. The tetracycline-resistant isolates harboured two plasmids: a 13476 bp Rep3-family plasmid of the GR17 group designated pAC13-1, which encodes the tetA(39) tetracycline-resistance gene, and pAC13-2, a 4872 bp cryptic PriCT-1-family plasmid of a new Acinetobacter plasmid group, GR60. The tetA(39) gene was in a 2 001 bp fragment flanked by XerC/XerD recombination sites characteristic of a mobile pdif module. Both plasmids also harboured mobilisation/transfer-related genes.
Genome sequencing of A. nosocomialis isolates led to the discovery of two novel plasmids, one of which encodes the tetA(39) tetracycline-resistant gene in a mobile pdif module. The high degree of genetic relatedness among the three tetracycline-resistant A. nosocomialis isolates is indicative of nosocomial transmission.
分析 2011 年从马来西亚登嘉楼州获得的 4 株存档的医院不动杆菌临床分离株（分别命名为 AC13、AC15、AC21 和 AC25）的基因组序列，以确定它们的遗传相关性和抗微生物药物耐药性的基础。
使用纸片扩散法测定不动杆菌分离株的抗微生物药敏谱。使用 Illumina NextSeq 平台进行基因组测序。
这 4 株不动杆菌对头孢噻肟耐药，而其中 3 株（即 AC13、AC15 和 AC25）对四环素耐药。所有 4 株分离株对头孢噻肟耐药的原因可能是 bla 编码的头孢菌素酶基因的携带。系统发育分析表明，这 3 株四环素耐药分离株密切相关，平均核苷酸同一性为 99.9%，提示为医院内传播，而 AC21 与这 3 株分离株相比，平均核苷酸同一性为 97.9%。这 3 株四环素耐药分离株携带 2 个质粒：一个 13476 bp 的 Rep3 家族质粒，属于 GR17 组，命名为 pAC13-1，它编码 tetA(39) 四环素耐药基因，以及 pAC13-2，一个 4872 bp 的隐秘 PriCT-1 家族质粒，属于新的不动杆菌质粒组，GR60。tetA(39) 基因位于 XerC/XerD 重组位点特征的 2001 bp 片段内，这是一个移动的 pdif 模块。这两个质粒还携带了移动/转移相关基因。
对不动杆菌分离株进行基因组测序发现了两个新的质粒，其中一个质粒在一个移动的 pdif 模块中编码 tetA(39) 四环素耐药基因。3 株四环素耐药的不动杆菌分离株具有高度的遗传相关性，提示存在医院内传播。
