P-1357. Molecular Mechanisms of Carbapenemase Genes Dissemination in Klebsiella pneumoniae in Two Colombian Cities (2018-2021)
Authors: Bolano-Ardila Nalleth Danieyis , De La Cadena Elsa , Rodríguez José Y , Marin Adriana , Villegas Maria Virginia , Mojica Maria F 
Published: January 2025

Abstract

Background
Colombia has been endemic for KPC for decades, mainly due to the clonal dissemination of blaKPC-3 among carbapenemase-producing K. pneumoniae (CP-Kp) sequence type (ST) 258 and plasmid dissemination of blaKPC-2 among different species of Gram-negatives. However, a recent surge in the detection of blaNDM among CP-Kp has raised concerns. Herein, we aimed to understand the dynamics of transmission of carbapenemase genes among CP-Kp clinical isolates in two cities of Colombia.Fig. 1.Molecular characterization of 31 CP-Kp collected between 2018 - 2019.MLST: Multi-locus sequence type; KL: capsule locus type; wzi: wzi alleles. Blue squares represent presence, gray absence.

Methods
We conducted a surveillance study in 7 hospitals in two Colombian cities, Valledupar and Barranquilla. Isolates were collected between 2018 and 2021, identified, and typed initially using rep-PCR. A subset of isolates was chosen for Whole Genome Sequencing on the Illumina platform based on pulsed-field gel electrophoresis (PFGE) pulsotypes. De-novo assembly and maximum likelihood phylogenetic analyses were performed.Fig.2.Virulence determinants and incompatibility groups of plasmids found in 31 CP-Kp.Blue squares represent presence, gray absence.

Results
A total of 89 CP-Kp isolates were recovered from infected patients, the majority of which produced KPC (64/89; 72%) and NDM (20/89; 22.5%); co-production of KPC and NDM or VIM was detected in 4/89 (4.5%) isolates. Following PFGE, 31 isolates were sequenced. Fig. 1 shows the relationship between the 12-sequence type (STs) identified and specific bla genes. Notably, ST11 was associated with blaKPC-3, whereas blaKPC-2 and blaNDM-1 were associated with several STs. One isolate harbored 3 carbapenemase genes, blaKPC-2, blaNDM-1, and blaVIM-24. Among other bla genes, blaOXA-1 and blaCTX-M-15 were found in 81% and 61% of the isolates, respectively. Most (81%) of blaKPC-2 and blaKPC-3 genes were found within a Tn4401b structure, followed by Tn4401a and non-Tn44 elements (NTEKPC; 9.5% each). Most isolates (90%) carried a complete mrk operon, associated with biofilm production, while the genes encoding siderophores fyuA and ybt were present in 58% and 51% of the isolates, respectively. Lastly, IncF plasmids were the most common type found among CP-Kp (Fig.2)

Conclusion
Although KPC remains the most common carbapenemase among CP-Kp, the rise of NDM associated with plasmid dissemination within different STs is concerning. Moreover, detecting CP-Kp isolates co-producing carbapenemases of different molecular classes poses a clinical challenge, as therapeutic options are scarce.

Disclosures
Maria Virginia Villegas, MD, bioMérieux: Advisor/Consultant|bioMérieux: Grant/Research Support|Merck Sharp and Dohme: Advisor/Consultant|Merck Sharp and Dohme: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support|WEST: Advisor/Consultant|WEST: Grant/Research Support