Emergence of Multidrug-Resistant NDM-5-Producing ST307 Klebsiella pneumoniae in Uruguay, 2023

Carbapenem and colistin-resistant Klebsiella pneumoniae pose a significant threat to public health, particularly in intensive care units, due to high morbidity and mortality rates. This study aimed to analyze five NDM carbapenemase-producing multidrug-resistant K. pneumoniae isolates from different hospitals. Antimicrobial susceptibility testing, hypermucoviscosity analysis, biofilm production assessment, MLST, PCR, and whole-genome sequencing were conducted. All isolates harbored NDM-5 metallo-β-lactamase, belonging to MLST 307, were biofilm producers and exhibited a stop codon (Q30) along MgrB. Genomic analysis revealed multiple-replicon plasmids carrying resistance genes, notably bla NDM-5 , bla CTX-M-15 , rmtB , and qnrB1 , with complex genetic structures encoding several mobile genetic elements, including the Tn3 family and IS26. All isolates harbored wzi 173 (capsule-locus KL102), iutA (a siderophore-associated gene), and the type 3 fimbriae mrkABCDFHIJ operon. The core genome single nucleotide polymorphisms (SNPs) analysis suggests the circulation of two strains of ST307 clone (SNPs range differences 4–77). These findings highlight the potential plasticity of the high-risk ST307 clone and the urgent need for surveillance and intervention strategies to combat antimicrobial resistance. To our knowledge, this is the first report of K. pneumoniae ST307 carrying bla NDM-5 and the first description of ST307 in Uruguay. The presence of bla NDM-5 and pan-aminoglycoside resistance rmtB genes are identified for the first time in Uruguay.