Clonal Dissemination of Pandrug-Resistant ST392KL27 in a Tertiary Care Hospital in Mexico.

The global emergence of multidrug- and pandrug-resistant poses a critical threat to public health, particularly in hospital settings. This study describes a nosocomial outbreak caused by in a tertiary-care hospital in Mexico and provides a comprehensive genomic analysis of six clinical isolates. All isolates exhibited pandrug resistance, including carbapenems and colistin. Whole-genome sequencing identified 37 antimicrobial resistance genes, including NDM-1, OXA-1, CTX-M-15, and a B R256G mutation associated with colistin resistance. Two conjugative plasmids (pAA046 and pAA276) carried multiple resistance genes and mobile genetic elements. Although all isolates harbored CRISPR-Cas type I-E systems, no spacers matched resistance plasmids, suggesting functional inactivity. Capsular typing identified the KL27 locus with the 187 allele. Phylogenetic and cgMLST analyses confirmed clonal dissemination and close genetic relatedness to strains from Europe and the USA. Despite the absence of classical hypervirulence markers, the presence of , , and genes indicates adaptation to the hospital environment. These findings confirm the clonal spread of pandrug-resistant ST392-KL27 in a Mexican hospital, underscoring the role of plasmid-mediated resistance and the potential for global dissemination.