Genome sequence of a tigecycline-resistant Acinetobacter seifertii recovered in human bloodstream infection in China

Objectives: The phylogenetic characteristics of Acinetobacter seifertii clinical strain are not well-studied. Here, we reported one tigecycline-resistant ST1612Pasteur A. seifertii isolated from bloodstream infections (BSI) in China .Methods: Antimicrobial susceptibility tests were conducted via broth microdilution. Whole-genome se-quencing (WGS) was performed and annotation was conducted using rapid annotations subsystems tech-nology (RAST) server. Multilocus sequence typing (MLST), capsular polysaccharide (KL), and lipoolygosac-charide (OCL) were analysed using PubMLST and Kaptive. Resistance genes, virulence factors, and compar-ative genomics analysis were performed. Cloning, mutations of efflux pump-related genes, and expression level were further investigated.Results: The draft genome sequence of A. seifertii ASTCM strain is made up of 109 contigs with a total length of 4,074,640 bp. Based on the RAST results, 3923 genes that belonged to 310 subsystems were annotated. Acinetobacter seifertii ASTCM was ST1612Pasteur with KL26 and OCL4, respectively. It was re-sistant to gentamicin and tigecycline. ASTCM harboured tet(39), sul2, and msr(E)-mph(E), and one amino acid mutation in Tet(39) (T175A) was further identified. Nevertheless, the signal mutation failed to con-tribute to susceptibility change of tigecycline. Of note, several amino acid substitutions were identified in AdeRS, AdeN, AdeL, and Trm, which could lead to overexpression of adeB, adeG, and adeJ efflux pump genes and further possibly lead to tigecycline resistance. Phylogenetic analysis showed that a huge diver-sity was observed among A. seifertii strains based on 27-52,193 SNPs difference.Conclusion: In summary, we reported a tigecycline-resistant ST1612Pasteur A. seifertii in China. Early de-tection is recommended to prevent their further spread in clinical settings. & COPY; 2023 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )