Overproduction of active efflux pump and variations of OprD dominate in imipenem-resistant Pseudomonas aeruginosa isolated from patients with bloodstream infections in Taiwan

BMC Microbiology

Research Article

Po-Ren Hsueh¹  Cheng-Yen Kao²  Kuei-Hsiang Hung²  Hsiu-Mei Wu²  Jiunn-Jong Wu³  Shu-Sheng Chen⁴  Jing-Jou Yan⁵ 

[1] Department of Internal Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan;Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan;Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan;Department of Biotechnology and Laboratory Science in Medicine, School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan;Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan;Department of Pathology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan;

关键词: Imipenem;    Pseudomonas aeruginosa;    β-lactamase;    Efflux pump;    OprD;   

DOI  :  10.1186/s12866-016-0719-2

 received in 2015-08-13, accepted in 2016-05-30,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundThe emergence of imipenem-resistant Pseudomonas aeruginosa (IRPA) has become a great concern worldwide. The aim of this study was to investigate resistance mechanisms associated with bloodstream isolated IRPA strains in Taiwan.ResultsA total of 78 non-duplicated IRPA isolates were isolated from patients with bloodstream infection. The average prevalence of imipenem-resistance in those isolates was 5.9 % during a 10-year longitudinal surveillance in Taiwan. PFGE results showed high clonal diversity among the 78 isolates. VIM-2, VIM-3, OXA-10, and OXA-17 β-lactamases were identified in 2 (2.6 %), 3 (3.8 %), 2 (2.6 %), and 1 (1.3 %) isolates, respectively. Active efflux pumps, AmpC β-lactamase overproduction, and extended-spectrum AmpC cephalosporinases (ESACs) were found in 58 (74.4 %), 25 (32.1 %) and 15 (19.2 %) of IRPA isolates, respectively. oprD mutations with amino acid substitution, shortened putative loop L7, premature stop codon caused by point mutation, frameshift by nucleotide insertion or deletion, and interruption by insertion sequence were found in 19 (24.4 %), 18 (23.1 %), 15 (19.2 %), 14 (17.9 %), and 10 (12.8 %) of isolates, respectively.ConclusionsThis study suggests that alterations in the OprD protein and having an active efflux pump are the main mechanisms associated with bloodstream isolated IRPA. Overproduction of AmpC, ESACs, and the presence of VIM- and OXA-type β-lactamases play additional roles in reduced susceptibility to imipenem in P. aeruginosa isolates in Taiwan.

【 授权许可】

CC BY   
© The Author(s). 2016