Publications

Authors:

Coccitto, Sonia Nina; Cinthi, Marzia; Simoni, Serena; Pocognoli, Antonella; Zeni, Guido; Mazzariol, Annarita; Morroni, Gianluca; Mingoia, Marina; Giovanetti, Eleonora; Brenciani, Andrea; Vignaroli, Carla

Title:

Genetic analysis of vancomycin-variable Enterococcus faecium clinical isolates in Italy

Year:

2024

Type of item:

Articolo in Rivista

Tipologia ANVUR:

Articolo su rivista

Language:

Inglese

Referee:

No

Name of journal:

European Journal of Clinical Microbiology and Infectious Diseases

ISSN of journal:

0934-9723

N° Volume:

43

Number or Folder:

4

Page numbers:

673-682

Keyword:

Enterococcus faecium; ST1478; Tn1546; Vancomycin variable enterococci; pstS-null; vanA

Short description of contents:

Purpose: To investigate the occurrence of vancomycin-variable enterococci (VVE) in a hospital in central Italy. Methods: vanA positive but vancomycin-susceptible Enterococcus faecium isolates (VVE-S) were characterized by antibiotic susceptibility tests, molecular typing (PFGE and MLST), and WGS approach. The reversion of VVE-S to a resistant phenotype was assessed by exposure to increasing vancomycin concentrations, and the revertant isolates were used in filter mating experiments. qPCR was used to analyze the plasmid copy number. Results: Eleven putative VVE-S were selected. WGS revealed two categories of vanA cluster plasmid located: the first type showed the lack of vanR, the deletion of vanS, and an intact vanH/vanA/vanX cluster; the second type was devoid of both vanR and vanS and showed a deletion of 544-bp at the 5'-end of the vanH. Strains (n = 7) carrying the first type of vanA cluster were considered VVE-S and were able to regain a resistance phenotype (VVE-R) in the presence of vancomycin, due to a 44-bp deletion in the promoter region of vanH/vanA/vanX, causing its constitutive expression. VVE-R strains were not able to transfer resistance by conjugation, and the resistance phenotype was unstable: after 11 days of growth without selective pressure, the revertants were still resistant but showed a lower vancomycin MIC. A higher plasmid copy number in the revertant strains was probably related to the resistance phenotype. Conclusion: We highlight the importance of VVE transition to VRE under vancomycin therapy resulting in a potential failure treatment. We also report the first-time identification of VVE-S isolates pstS-null belonging to ST1478.

Note:

Epub 2024 Jan 31

Product ID:

137471

Handle IRIS:

11562/1118326

Last Modified:

April 5, 2024

Bibliographic citation:

Coccitto, Sonia Nina; Cinthi, Marzia; Simoni, Serena; Pocognoli, Antonella; Zeni, Guido; Mazzariol, Annarita; Morroni, Gianluca; Mingoia, Marina; Giovanetti, Eleonora; Brenciani, Andrea; Vignaroli, Carla, Genetic analysis of vancomycin-variable Enterococcus faecium clinical isolates in Italy «European Journal of Clinical Microbiology and Infectious Diseases» , vol. 43 , n. 4 , 2024 , pp. 673-682

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