A 19-year longitudinal study to characterize carbapenem-nonsusceptible Acinetobacter isolated from patients with bloodstream infections and the contribution of conjugative plasmids to carbapenem resistance and virulence.
Journal
Journal of Microbiology Immunology and Infection
Journal Volume
57
Journal Issue
2
Start Page
288
End Page
299
ISSN
1995-9133
Date Issued
2024-04
Author(s)
Chen, Pek Kee
Lee, Yi-Tzu
Liu, Chia-Ying
Thuy, Tran Thi Dieu
Anh, Kieu
Wu, Jiunn-Jong
Liao, Chun-Hsing
Chen, Yu-Chen
Kao, Cheng-Yen
Abstract
Background: This study aimed to characterize carbapenem-nonsusceptible Acinetobacter (CNSA) isolated from patients with bacteremia from 1997 to 2015. Methods: A total of 173 CNSA (12.3%) was recovered from 1403 Acinetobacter isolates. The presence of selected β-lactamase genes in CNSA was determined by PCR amplification. The conjugation test was used to determine the transferability of metallo-β-lactamase (MBL)-carrying plasmids. Whole genome sequencing in combination with phenotypic assays was carried out to characterize MBL-plasmids. Results: In general, a trend of increasing numbers of CNSA was observed. Among the 173 CNSA, A. baumannii (54.9%) was the most common species, followed by A. nosocomialis (23.1%) and A. soli (12.1%). A total of 49 (28.3%) CNSA were extensively drug-resistant, and all were A. baumannii. The most common class D carbapenemase gene in 173 CNSA was blaOXA-24-like (32.4%), followed by ISAba1-blaOXA-51-like (20.8%), ISAba1-blaOXA-23 (20.2%), and IS1006/IS1008-blaOXA-58 (11.6%). MBL genes, blaVIM-11, blaIMP-1, and blaIMP-19 were detected in 9 (5.2%), 20 (11.6%), and 1 (0.6%) CNSA isolates, respectively. Transfer of MBL genes to AB218 and AN254 recipient cells was successful for 7 and 6 of the 30 MBL-plasmids, respectively. The seven AB218-derived transconjugants carrying MBL-plasmids produced less biofilm but showed higher virulence to larvae than recipient AB218. Conclusions: Our 19-year longitudinal study revealed a stable increase in CNSA during 2005–2015. blaOXA-24-like, ISAba1-blaOXA-51-like, and ISAba1-blaOXA-23 were the major determinants of Acinetobacter carbapenem resistance. MBL-carrying plasmids contribute not only to the carbapenem resistance but also to A. baumannii virulence.
Subjects
Acinetobacter spp.
Bacteremia
Carbapenem resistance
Carbapenemase
Conjugative plasmid
Virulence
bla(IMP)
bla(VIM)
Publisher
Elsevier Ltd
Type
journal article