Li Puyuan, Huang Yong, Yu Lan, Liu Yannan, Niu Wenkai, Zou Dayang, Liu Huiying, Zheng Jing, Yin Xiuyun, Yuan Jing, Yuan Xin, Bai Changqing
Department of Respiratory and Critical Care Diseases, 307th Hospital of PLA, Beijing 100071, China.
State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
Int J Infect Dis. 2017 Sep;62:94-101. doi: 10.1016/j.ijid.2017.07.005. Epub 2017 Jul 10.
Heteroresistance is a phenomenon in which there are various responses to antibiotics from bacterial cells within the same population. Here, we isolated and characterised an imipenem heteroresistant Acinetobacter baumannii strain (HRAB-85).
The genome of strain HRAB-85 was completely sequenced and analysed to understand its antibiotic resistance mechanisms. Population analysis and multilocus sequence typing were performed.
Subpopulations grew in the presence of imipenem at concentrations of up to 64μg/mL, and the strain was found to belong to ST208. The total length of strain HRAB-85 was 4,098,585bp with a GC content of 39.98%. The genome harboured at least four insertion sequences: the common ISAba1, ISAba22, ISAba24, and newly reported ISAba26. Additionally, 19 antibiotic-resistance genes against eight classes of antimicrobial agents were found, and 11 genomic islands (GIs) were identified. Among them, GI3, GI10, and GI11 contained many ISs and antibiotic-resistance determinants.
The existence of imipenem heteroresistant phenotypes in A. baumannii was substantiated in this hospital, and imipenem pressure, which could induce imipenem-heteroresistant subpopulations, may select for highly resistant strains. The complete genome sequencing and bioinformatics analysis of HRAB-85 could improve our understanding of the epidemiology and resistance mechanisms of carbapenem-heteroresistant A. baumannii.
异质性耐药是指同一细菌群体中的细菌细胞对抗生素有多种反应的现象。在此，我们分离并鉴定了一株亚胺培南异质性耐药鲍曼不动杆菌菌株（HRAB-85）。
对HRAB-85菌株的基因组进行全序列测定和分析，以了解其抗生素耐药机制。进行了群体分析和多位点序列分型。
亚群体在浓度高达64μg/mL的亚胺培南存在下生长，该菌株被发现属于ST208。HRAB-85菌株的全长为4,098,585bp，GC含量为39.98%。该基因组至少含有四个插入序列：常见的ISAba1、ISAba22、ISAba24和新报道的ISAba26。此外，还发现了针对八类抗菌剂的19个抗生素耐药基因，并鉴定出11个基因组岛（GI）。其中，GI3、GI10和GI11包含许多插入序列和抗生素耐药决定簇。
该医院证实了鲍曼不动杆菌中亚胺培南异质性耐药表型的存在，可诱导亚胺培南异质性耐药亚群体的亚胺培南压力可能会选择出高耐药菌株。对HRAB-85进行全基因组测序和生物信息学分析有助于我们更好地了解碳青霉烯异质性耐药鲍曼不动杆菌的流行病学和耐药机制。
