Antibiotics (Mar 2021)

Molecular Analysis of Polymyxin Resistance among Carbapenemase-Producing <i>Klebsiella pneumoniae</i> in Colombia

  • Elsa De La Cadena,
  • María Fernanda Mojica,
  • Juan Carlos García-Betancur,
  • Tobías Manuel Appel,
  • Jessica Porras,
  • Christian José Pallares,
  • Juan Sebastián Solano-Gutiérrez,
  • Laura J. Rojas,
  • María Virginia Villegas

DOI
https://doi.org/10.3390/antibiotics10030284
Journal volume & issue
Vol. 10, no. 3
p. 284

Abstract

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Polymyxin resistance in Klebsiella pneumoniae has been attributed to mutations in mgrB, phoPQ, pmrAB, and crrAB and to the presence of mcr plasmid-mediated genes. Herein, we describe the molecular characteristics of 24 polymyxin- and carbapenem-resistant K. pneumoniae isolates recovered from six Colombian cities between 2009 and 2019. Minimum inhibitory concentrations (MICs) to polymyxin were confirmed by broth microdilution, and whole-genome sequencing was performed to determine sequence type, resistome, and mutations in the genes related to polymyxin resistance, as well the presence of mcr. The results showed high-level resistance to polymyxin (MICs ≥ 4 μg/mL). blaKPC-3 was present in the majority of isolates (17/24; 71%), followed by blaKPC-2 (6/24; 25%) and blaNDM-1 (1/24; 4%). Most isolates belonged to the CG258 (17/24; 71%) and presented amino acid substitutions in PmrB (22/24; 92%) and CrrB (15/24; 63%); mutations in mgrB occurred in only five isolates (21%). Additional mutations in pmrA, crrA, and phoPQ nor any of the mcr resistance genes were identified. In conclusion, we found clonal dissemination of polymyxin and carbapenem-resistant K. pneumoniae isolates in Colombia, mainly associated with CG258 and blaKPC-3. Surveillance of this multidrug-resistant clone is warranted due to the limited therapeutic options for the treatment of carbapenem-resistant K. pneumoniae infections.

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