Circulation of a Unique Clone, ST147 NDM-1/OXA-48, in Two Diverse Hospitals in Calabria (Italy).

Carbapenem-resistant has become endemic in Europe, including in Italy, where its prevalence has risen dramatically, primarily due to epidemic clones harboring metallo-enzymes. This study aims to investigate the dissemination of strains co-producing OXA-48 and NDM-1 between two hospitals in southern Italy using molecular analyses. A total of 49 strains, predominantly co-producing OXA-48 and NDM-1, were collected between March and December 2023. Antibiotic susceptibility testing was conducted following EUCAST guidelines. Whole-genome sequencing (Illumina MiSeq) and bioinformatics tools (CARD, CLC Genomics Workbench) were used to identify resistance and virulence genes, capsule loci, and phylogenetic relationships. All isolates exhibited multidrug-resistant or extensively drug-resistant profiles, including resistance to ceftazidime/avibactam and meropenem/vaborbactam. Genomic analysis revealed diverse resistance genes such as , , , and variants. Virulence genes associated with capsules, fimbriae, and siderophores were widespread. Most strains were classified as ST147 by MLST and contained various plasmids known to carry antimicrobial resistance. Phylogenetic analysis confirmed their clonal relatedness, highlighting the intra-hospital dissemination of high-risk clones. High-risk clones, particularly ST147, pose significant challenges in healthcare settings due to the extensive antimicrobial resistance driven by plasmid-borne resistance genes, including those that co-produce carbapenemases, like and . Molecular monitoring of these clones is essential for improving targeted infection control strategies, mitigating the spread of multidrug-resistant pathogens, and managing their clinical impact effectively.