Fitness cost of vancomycin-resistant Enterococcus faecium plasmids associated with hospital infection outbreaks

• Type: Article in International Scientific Journal
• Date: 2021

Authors

Tedim, AP (Author) Other; Lanza, VF (Author) Other; Rodriguez, CM (Author) Other; Freitas, AR (Author) Other; Novais, Carla (Author) FFUP; Luisa Peixe (Author) FFUP; Baquero, F (Author) Other; Coque, TM (Author) Other

Journal

Title: Journal of Antimicrobial Chemotherapy

Vol. 76

Pages: 2757-2764

ISSN: 0305-7453

Publisher: Oxford University Press

Indexing

ISI Web of Knowledge - 1 Citation

Scopus - 3 Citations

Other information

Authenticus ID: P-00V-Y20

DOI: 10.1093/jac/dkab249

Abstract (EN): Background: Vancomycin resistance is mostly associated with Enterococcus faecium due to Tn1546-vanA located on narrow- and broad-host plasmids of various families. This study's aim was to analyse the effects of acquiring Tn1546-carrying plasmids with proven epidemicity in different bacterial host backgrounds. Methods: Widespread Tn1546-carrying plasmids of different families RepA_N (n=5), Inc18 (n=4) and/or pHT beta (n=1), and prototype plasmids RepA_N (pRUM) and Inc18 (pRE25, pIP501) were analysed. Plasmid transferability and fitness cost were assessed using E. faecium (GE1, 64/3) and Enterococcus faecalis (JH2-2/FA202/UV202) recipient strains. Growth curves (Bioscreen C) and Relative Growth Rates were obtained in the presence/absence of vancomycin. Plasmid stability was analysed (300 generations). WGS (Illumina-MiSeq) of non-evolved and evolved strains (GE1/64/3 transconjugants, n=49) was performed. SNP calling (Breseq software) of non-evolved strains was used for comparison. Results: All plasmids were successfully transferred to different E. faecium clonal backgrounds. Most Tn1546-carrying plasmids and Inc18 and RepA_N prototypes reduced host fitness (-2% to 18%) while the cost of Tn1546 expression varied according to the Tn1546-variant and the recipient strain (9%-49%). Stability of Tn1546-carrying plasmids was documented in all cases, often with loss of phenotypic resistance and/or partial plasmid deletions. SNPs and/or indels associated with essential bacterial functions were observed on the chromosome of evolved strains, some of them linked to increased fitness. Conclusions: The stability of E. faecium Tn1546-carrying plasmids in the absence of selective pressure and the high intra-species conjugation rates might explain the persistence of vancomycin resistance in E. faecium populations despite the significant burden they might impose on bacterial host strains.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8