Plasmid Promiscuity Explains High Endemicity of KPC-2 Among Colombian Enterobacteriaceae

Abstract

BackgroundCarbapenemase-producing Enterobacteriaceae (CPE) currently pose a significant global public health threat. KPC carbapenemases are highly endemic in Colombia mostly among Enterobacteriaceae. In Klebsiella pneumoniae (Kpn), horizontal transfer of genes encoding KPC and expansion of isolates belonging to clonal group (CG) 258 resulted in epidemic levels of carbapenemase-producing Kpn. We aimed to understand the dynamics of transmission of KPC-genes among CPE infecting and colonizing patients in an endemic area of Colombia.MethodsWe conducted a surveillance study in 3 hospitals around Medellin, Antioquia (November 2013 to October 2015) that included patients colonized and infected (by physician criteria) with CPE. The isolates were collected, identified and typed initially using rep-PCR. A subset of isolates were chosen for Whole Genome Sequencing on the Illumina platform based on initial molecular characterization. De-novo assembly and maximum likelihood phylogenetic analyses were performed in all sequenced isolates.ResultsA total of 131 KPC-producing Enterobacteriaceae isolates were recovered from 77 colonized and 29 infected patients. A total of 76 selected isolates were sequenced. In Kpn, compartmentalization of KPC-3 within CG258 was observed, whereas KPC-2 was identified in different genetic backgrounds but not in CG258. In E. coli, blaKPC-2 was found in two clusters belonging to ST131 and ST349. In one hospital both Kpn (ST36,15,101,140, 502) and E. coli shared a 56 Kb plasmid harboring blaKPC-2 with high degree of identity to the conjugative IncN plasmid N3. The blaKPC-2 gene was found within a variation of Tn4401b harboring ISKpn6 and carrying both a Tn3-transposase and a resolvase. E. cloacae, C. freundii and S. marcescens only harbored KPC-2 (and not KPC-3) within the same Tn4401b structure.ConclusionThe KPC epidemic in an area of high endemicity in Colombia is driven by horizontal transfer of plasmids harboring blaKPC-2 among members of the Enterobacteriaceae family. These findings are consistent with a KPC-plasmid epidemic rather than clonal expansion of a successful genetic lineage. Controlling the KPC epidemic in Colombia would be challenging and is likely influenced by antibiotic consumption rather than patient to patient transmission.Disclosures A. M. Rada, COLCIENCIAS: Student, Research grant and Research support; N. Orozco, COLCIENCIAS: Research Contractor, Salary; C. Hernández-Gómez, Merck Sharp and Dohme, Pfizer: Consultant, Consulting fee; C. Pallares, Merck Sharp & Dohme, Pfizer: Consultant, Consulting fee; M. V. Villegas, Merck Sharp & Dohme, Pfizer: Consultant, Consulting fee and Research support; E. Restrepo, COLCIENCIAS: Investigator, Research support