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J Antimicrob Chemother DOI:10.1093/jac/dky039

Transferable vancomycin resistance in clade B commensal-type Enterococcus faecium.

Publication TypeJournal Article
Year of Publication2018
AuthorsLebreton, F, Valentino, MD, Schaufler, K, Earl, AM, Cattoir, V, Gilmore, MS
JournalJ Antimicrob Chemother
Date Published2018 06 01
KeywordsAnti-Bacterial Agents, Bacterial Proteins, Cross Infection, Enterococcus faecium, Feces, Genome, Bacterial, Gram-Positive Bacterial Infections, Humans, Immunocompromised Host, Microbial Sensitivity Tests, Operon, Phylogeny, Plasmids, Symbiosis, Vancomycin, Vancomycin Resistance, Vancomycin-Resistant Enterococci

Objectives: Vancomycin-resistant Enterococcus faecium is a leading cause of MDR hospital infection. Two genetically definable populations of E. faecium have been identified: hospital-adapted MDR isolates (clade A) and vancomycin-susceptible commensal strains (clade B). VanN-type vancomycin resistance was identified in two isolates of E. faecium recovered from blood and faeces of an immunocompromised patient. To understand the genomic context in which VanN occurred in the hospitalized patient, the risk it posed for transmission in the hospital and its origins, it was of interest to determine where these strains placed within the E. faecium population structure.

Methods: We obtained the genome sequence of the VanN isolates and performed comparative and functional genomics of the chromosome and plasmid content.

Results: We show that, in these strains, VanN occurs in a genetic background that clusters with clade B E. faecium, which is highly unusual. We characterized the chromosome and the conjugative plasmid that carries VanN resistance in these strains, pUV24. This plasmid exhibits signatures of in-host selection on the vanN operon regulatory system, which are associated with a constitutive expression of vancomycin resistance. VanN resistance in clade B strains may go undetected by current methods.

Conclusions: We report a case of vancomycin resistance in a commensal lineage of E. faecium responsible for an atypical bacteraemia in an immunocompromised patient. A reservoir of transferable glycopeptide resistance in the community could pose a concern for public health.


Alternate JournalJ. Antimicrob. Chemother.
PubMed ID29462403
PubMed Central IDPMC5961315
Grant ListHHSN272200900018C / AI / NIAID NIH HHS / United States
P01 AI083214 / AI / NIAID NIH HHS / United States
R01 AI072360 / AI / NIAID NIH HHS / United States
U19 AI110818 / AI / NIAID NIH HHS / United States