Institute of Medical Technology, Peking University Health Science Center, Beijing, China.
Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China.
Microbiol Spectr. 2022 Jun 29;10(3):e0260421. doi: 10.1128/spectrum.02604-21. Epub 2022 May 31.
Carbapenem-resistant Acinetobacter baumannii (CRAB) is an opportunistic pathogen that has become a global threat. The dissemination of global clone 2 (GC2) CRAB has been well documented. Oxford sequence type (ST) 208 is one of the most prevalent lineages of A. baumannii GC2; however, its evolution and phylogeny are unclear. We collected 45 representative ST208 isolates from 14 cities in China between 1999 and 2018. Moreover, 411 ST208 genome sequences were downloaded from the GenBank database for comparison. The global ST208 phylogeny showed that ST208 might have originated from North America and subsequently evolved into two clades. Notably, the widespread OXA-23-producing ST208 A. baumannii was correlated with the transposon structure and dynamics of replicative transposition, and the Tn tandem structure of five copies of and potential circular intermediate of Tn were first detected. Furthermore, 15 Chinese ST208 isolates carried GR25 pABTJ1-like plasmids, which contained and have only been found in China in the last decade. In conclusion, our work suggests that replicative transposition contributes to the evolution and transmission of OXA-23-producing ST208 A. baumannii and highlights the new challenges posed by the epidemiological surveillance of globally distributed clonal groups via whole genome sequencing. ST208 as one of the most prevalent lineages of CRAB has caused several difficult-to-treat infections and outbreaks around the world. However, few studies have focused on evaluating the genetic background differences of ST208 A. baumannii isolated from very distant geographic regions. A comprehensive genomic analysis of 456 clinical strains of ST208 A. baumannii from a wide temporal and geographic range was performed in this study. Moreover, the mechanisms leading to the horizontal transfer of in ST208 A. baumannii are poorly understood. We first describe experimental evidence of the potential circular intermediate of Tn, and the Tn tandem structure of five copies of was first detected. The interbacterial transfer of genetic elements carrying resistance to last-line antibiotic carbapenems highlights the essential need to enhance epidemiologic surveillance.
耐碳青霉烯鲍曼不动杆菌（CRAB）是一种机会性病原体，已成为全球性威胁。全球克隆 2（GC2）CRAB 的传播已得到充分记录。牛津序列型（ST）208 是 GC2 鲍曼不动杆菌最常见的谱系之一；然而，其进化和系统发育尚不清楚。我们收集了 1999 年至 2018 年间中国 14 个城市的 45 株代表性 ST208 分离株。此外，还从 GenBank 数据库中下载了 411 株 ST208 基因组序列进行比较。全球 ST208 系统发育表明，ST208 可能起源于北美，随后进化为两个分支。值得注意的是，广泛传播的产 OXA-23 的 ST208 鲍曼不动杆菌与转座子结构和复制转座的动态相关，并且首次检测到 Tn 的五个拷贝的串联结构和潜在的 Tn 圆形中间产物。此外，15 株中国 ST208 分离株携带 GR25pABTJ1 样质粒，其中包含 ，并且仅在过去十年中在中国发现。总之，我们的工作表明，复制转座有助于产 OXA-23 的 ST208 鲍曼不动杆菌的进化和传播，并强调了通过全基因组测序进行全球分布克隆群的流行病学监测所带来的新挑战。ST208 作为 CRAB 最常见的谱系之一，已在全球范围内引起了几起难以治疗的感染和暴发。然而，很少有研究关注评估来自非常遥远地理区域的 ST208 鲍曼不动杆菌的遗传背景差异。本研究对来自广泛时间和地理范围的 456 株 ST208 鲍曼不动杆菌的临床株进行了全面的基因组分析。此外，导致 ST208 鲍曼不动杆菌中 水平转移的机制尚不清楚。我们首次描述了 Tn 潜在的圆形中间产物的实验证据，并且首次检测到 Tn 的五个拷贝的串联结构。携带对最后一线抗生素碳青霉烯类药物耐药性的遗传元件在细菌间的转移突出表明，加强流行病学监测是至关重要的。
