摘要
目标
2014年至2020年间，在荷兰的不同医院回收了五株人类临床耐多药（MDR）脆弱拟杆菌分离株，包括对美罗培南和甲硝唑的耐药性，并将其送往厌氧参考实验室进行全面鉴定。
方法
从具有无关背景的患者的各种临床标本中回收分离物。进行长读和短读测序，然后进行杂交组装，以研究移动遗传元件（MGE）和抗微生物耐药性基因（ARGs）的存在。
后果
在两个分离株中，cfxA基因存在于类似于Tn4555的转座子（Tn）上。在两个分离株中，存在一个带有cfxA基因的新Tn。四个分离株携带一个位于pBFS01_2质粒上的nimE基因。其中一个分离物含有一个携带带有IS1168的nimA基因的新质粒。tetQ基因存在于属于CTnDOT家族的新型偶联转座子（CTns）上。两个分离株携带一个新的tetQ质粒。这些分离物中的其他ARG，但不是MGE上的，是：cfiA、ermF、mef（EN2）和sul2。不同分离株携带的ARGs不同，并与观察到的表型抗性相对应。
结论
在五个耐多药脆弱芽孢杆菌分离株中发现了新的CTns、Tns和质粒，这补充了我们对厌氧菌中耐多药和水平基因转移的了解。
Abstract
Objectives
Five human clinical multidrug-resistant (MDR) Bacteroides fragilis isolates, including resistance to meropenem and metronidazole, were recovered at different hospitals in the Netherlands between 2014 and 2020 and sent to the anaerobic reference laboratory for full characterization.

Methods
Isolates were recovered from a variety of clinical specimens from patients with unrelated backgrounds. Long- and short-read sequencing was performed, followed by a hybrid assembly to study the presence of mobile genetic elements (MGEs) and antimicrobial resistance genes (ARGs).

Results
A cfxA gene was present on a transposon (Tn) similar to Tn4555 in two isolates. In two isolates a novel Tn was present with the cfxA gene. Four isolates harbored a nimE gene, located on a pBFS01_2 plasmid. One isolate contained a novel plasmid carrying a nimA gene with IS1168. The tetQ gene was present on novel conjugative transposons (CTns) belonging to the CTnDOT family. Two isolates harbored a novel plasmid with tetQ. Other ARGs in these isolates, but not on an MGE, were: cfiA, ermF, mef(EN2), and sul2. ARGs harboured differed between isolates and corresponded with the observed phenotypic resistance.

Conclusions
Novel CTns, Tns, and plasmids were encountered in the five MDR B. fragilis isolates, complementing our knowledge on MDR and horizontal gene transfer in anaerobic bacteria.

https://www.sciencedirect.com/science/article/pii/S1075996423000318