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

The global emergence of multidrug- and pandrug-resistant <i>Klebsiella pneumoniae</i> poses a critical threat to public health, particularly in hospital settings. This study describes a nosocomial outbreak caused by <i>K. pneumoniae</i> 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 <i>bla</i>NDM-1, <i>bla</i>OXA-1, <i>bla</i>CTX-M-15, and a <i>pmr</i>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 <i>wzi</i>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 <i>kfu</i>, <i>fimH</i>, and <i>mrkD</i> genes indicates adaptation to the hospital environment. These findings confirm the clonal spread of pandrug-resistant <i>K. pneumoniae</i> ST392-KL27 in a Mexican hospital, underscoring the role of plasmid-mediated resistance and the potential for global dissemination.