Persistence and multi-ward dissemination of vancomycin-resistant Enterococcus faecium ST17 clone in hospital settings in Slovakia 2017-2020.

OBJECTIVES

Hospital vancomycin-resistant Enterococcus faecium (VREfm) were evaluated in term of resistance and phylogenetic relatedness to estimate the location and possible route of transmission of resistance determinants.

METHODS

Hospital VREfm (n = 49) were collected in the northern part of Slovakia during 2017-2020. The collection was analysed for the presence of the van operon and 10 representatives were subjected to whole-genome sequencing using Illumina MiSeq platform. Obtained sequences were de novo assembled and the draft genome assemblies were analysed with respect to sequence type (ST), plasmid content, resistance and virulence genes, and the phylogenetic relatedness in single nucleotide polymorphisms (SNP).

RESULTS

All strains possessed the vanA operon. Ten selected evaluated isolates belonged to the clinically relevant clonal complex (CC) 17 and carried the vanHAX gene cluster conferring vancomycin resistance on mobile genetic elements, except for the isolate M17773 carrying the vanHAX gene cluster chromosomally. All isolates encoded resistance to quinolones (gyrA and parC mutations) and aminoglycosides [aac(6')-aph(2'')]. Four isolates from different wards and patients belonging to ST17 were closely related (6-50 SNP), suggesting long-term persistence of VREfm ST17 in hospital settings.

CONCLUSION

VREfm proved to harbour many genetic determinants of antimicrobial resistance. The plasmids carrying the vanA genes belonged to the conjugative broad-host families Inc18 and RepA_N, posing a threat to human health, especially in hospital settings. Moreover, four clinical isolates were phylogenetically related, pointing towards stable circulation of the ST17 VREfm clone in the hospital setting and underlining the necessity for continuous surveillance of glycopeptide-resistant pathogens.