Isolation and Whole-genome Sequence Analysis of the Imipenem Heteroresistant Acinetobacter baumannii Clinical Isolate HRAB-85. (September 2017)

• Record Type: Journal Article
• Authors: Li, Puyuan; Huang, Yong; Yu, Lan; Liu, Yannan; Niu, Wenkai; Zou, Dayang; Liu, Huiying; Zheng, Jing; Yin, Xiuyun; Yuan, Jing; Yuan, Xin; Bai, Changqing
• Is Part Of: International journal of infectious diseases. Volume 62(2017:Sep.)
• Page Start: 94
• Page End: 101
• Publication Date: 2017-09
• Subjects: Acinetobacter baumannii -- heteroresistance -- carbapenem -- genomic island -- insertion sequence; Communicable diseases -- Periodicals; Communicable Diseases -- Periodicals; Communicable diseases; Periodicals; Electronic journals; 616.9
• DOI: 10.1016/j.ijid.2017.07.005
• Languages: English
• ISSNs: 1201-9712

Abstract

Highlights: We isolated/characterised an imipenem heteroresistant A. baumannii strain (HRAB-85). Subpopulations grew in the presence of imipenem at concentrations of up to 64 μg/mL. The total length of strain HRAB-85 was 4, 098, 585 bp with a GC content of 39.98%. Whole-genome sequencing revealed four ISs and 19 antibiotic-resistance genes. Our results improve our understanding of heteroresistant A. baumannii . Abstract: Objectives: 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). Methods: 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. Results: Subpopulations grew in the presence of imipenem at concentrations of up to 64 μg/mL, and the strain was found to belong to ST208. The total length of strain HRAB-85 was 4, 098, 585 bp with a GC content of 39.98%. The genome harboured at least four insertion sequences: the common IS Aba1, IS Aba22, IS Aba24, and newly reported IS Aba26 . 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. Conclusions: 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 .