Vancomycin-resistant enterococci in Spanish hospitals: the experience of official network for the surveillance of resistant microorganisms RedLabRA, 2023–2024

Objectives RedLabRA is a network of microbiology laboratories for the genomic surveillance of antibiotic resistance. The aim of this study was to describe the actions undertaken by RedLabRA in response to an increase of vancomycin-resistant enterococci (VRE) in some Spanish regions. Methods RedLabRA designed a VRE surveillance organized in two phases: (1) a questionnaire to assess risk perception of VRE among the network’s Level 2 laboratories (LN2), and (2) collection of cases detected between April 2023 and March 2024, followed by WGS of a sample of vancomycin-resistant Enterococcus faecium (VREfm) isolates to investigate interregional dissemination. WGS was performed using the Illumina platform; MLST ( PubMLST.org scheme), cgMLST and phylogenetic relationships (Ridom SeqSphere+ v3.5.0), and resistome (Resfinder 4.7.2) were analysed. Results Nine of the 17 autonomous communities defined a priority scenario of VRE. 31 LN2 reported 1,958 VRE cases from 86 hospitals across 12 autonomous communities and the autonomous city Ceuta. The predominant species was E. faecium (97.1%). 317 VREfm isolates were included for WGS: 211 (66.6%) carried the van A gene, 90 (28.4%) van B, and 16 (5%) both genes. ST117 (34.7%), ST80 (27.1%), or ST1421 (25.6%) predominated. Using cgMLST (1,423 genes, cutoff of 5 alleles), 45 VREfm clusters were identified, of which eight involved at least three hospitals and were inter-regional. 51 (16.1%) isolates carried linezolid resistance mechanisms, mainly optr A+ cfr D. Conclusion VREfm had a highly uneven impact across Spanish regions. The inter-regional presence of VREfm isolates with high genetic similarity belonging to ST1421, ST117, and ST80 clones was detected. The emergence of E. faecium isolates carrying genes conferring resistance to vancomycin and linezolid requires ongoing surveillance.