Department of Clinical Laboratory, Hanzhong Central Hospital, Hanzhong, People's Republic of China; Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, People's Republic of China; Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.
Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, People's Republic of China; Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.
J Glob Antimicrob Resist. 2024 Sep;38:167-172. doi: 10.1016/j.jgar.2024.05.007. Epub 2024 May 19.
Acinetobacter pittii has emerged as an opportunistic nosocomial pathogen associated with hospital-acquired infections. The purpose of this study was to investigate the genetic structures of plasmids carrying carbapenemase genes bla and bla in A. pittii strains AR3676 and AR3651 isolated from patients.
Antimicrobial susceptibility testing was performed using broth microdilution. Whole-genome sequencing and bioinformatics analysis were performed to characterize the genome of A. pittii AR3676 and AR3651. Conjugation experiments were conducted to evaluate plasmid transferability. Phylogenetic and comparative genomic analysis were performed to explore the characteristics of carbapenem-resistant A. pittii isolates worldwide.
The AR3676 strain showed resistance to imipenem. The 19 700-bp plasmid pAR3676-OXA-58 harboured bla with genetic contexts consisting of a truncated ISAba3-like-bla-ISAba3. Additionally, the AR3651 strain showed resistance to imipenem and meropenem. The AR3651 genome comprised one 9,837-bp RepA_AB plasmid pAR3651-OXA-72 harbouring bla. This bla was flanked by XerC/XerD recombination sites. The conjugation of plasmids pAR3676-OXA-58 and pAR3651-OXA-72 from A. pittii to Acinetobacter baumannii ATCC 17978RIF failed three independent times. Phylogenetic analysis of A. pittii strains AR3676, AR3651, and a further 504 A. pittii strains collected between 1966 and 2022 from various geographic localities revealed genetic diversity with a heterogeneous distribution of carbapenemase genes.
A. pittii strains with a plasmid carrying bla or bla may serve as an important reservoir of carbapenemase genes. Carbapenemase genes on a single plasmid may facilitate their dissemination and persistence. Additionally, pdif sites and mobile elements play an important role in the mobilization of resistance genes and plasmid evolution.
鲍曼不动杆菌已成为与医院获得性感染相关的机会性病原体。本研究旨在研究从患者中分离出的鲍曼不动杆菌 AR3676 和 AR3651 菌株中携带碳青霉烯酶基因 bla 和 bla 的质粒的遗传结构。
采用肉汤微量稀释法进行抗菌药物敏感性试验。对鲍曼不动杆菌 AR3676 和 AR3651 的基因组进行全基因组测序和生物信息学分析。进行接合实验以评估质粒的可转移性。进行系统发育和比较基因组分析，以探讨全球耐碳青霉烯鲍曼不动杆菌分离株的特征。
AR3676 株对亚胺培南表现出耐药性。19700bp 的质粒 pAR3676-OXA-58 携带 bla ，其遗传结构由截断的 ISAba3-like-bla-ISAba3 组成。此外，AR3651 株对亚胺培南和美罗培南表现出耐药性。AR3651 基因组包含一个 9837bp 的 RepA_AB 质粒 pAR3651-OXA-72 ，该质粒携带 bla 。该 bla 被 XerC/XerD 重组位点包围。三次独立的鲍曼不动杆菌 ATCC 17978RIF 向鲍曼不动杆菌 AR3676 和 AR3651 的质粒 pAR3676-OXA-58 和 pAR3651-OXA-72 的接合均未成功。对 1966 年至 2022 年期间从不同地理区域收集的 AR3676、AR3651 及另外 504 株鲍曼不动杆菌菌株的系统发育分析显示，存在遗传多样性，碳青霉烯酶基因呈异质分布。
携带 bla 或 bla 的质粒的鲍曼不动杆菌菌株可能是碳青霉烯酶基因的重要储存库。单个质粒上的碳青霉烯酶基因可能有助于其传播和持续存在。此外，pdif 位点和移动元件在耐药基因的转移和质粒进化中发挥重要作用。
