Antibiotic pressure on the acquisition and loss of antibiotic resistance genes in Klebsiella pneumoniae

Patricia J. Simner, Annukka A.R. Antar, Stephanie Hao, James Gurtowski, Pranita D. Tamma, Clare Rock, Belita N.A. Opene, Tsigereda Tekle, Karen C. Carroll, Michael C. Schatz, Winston Timp

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Objectives: In this study, we characterize a concurrent disseminated infection with a virulent hypermucoviscous (HMV) Klebsiella pneumoniae and an OXA-181-producing XDR K. pneumoniae froma patient with recent hospitalization in India. During exposure to meropenem therapy, the highly susceptible HMV K. pneumoniae became resistant to carbapenems, consistent with the acquisition of bla OXA-181 . Methods: Twelve K. pneumoniae isolates were recovered from the patient and the hospital room environment over a 3month hospitalization. Phenotypic and molecular studies were completed to characterize the isolates. Oxford Nanopore and Illumina MiSeq WGS were performed to study phylogeny (MLST and SNPs), plasmids and virulence genes and demonstrate changes in the organism's resistome that occurred over time. Results: WGS revealed that the HMV K. pneumoniae belonged to ST23 and harboured an IncH1B virulence plasmid, while the XDR K. pneumoniae belonged to ST147 and possessed two MDR plasmids (IncR and IncFII), the blaOXA-181-bearing ColKP3 plasmid and chromosomal mutations conferring the XDR phenotype. Sequential isolates demonstrated plasmid diversification (fusion of the IncR and IncFII plasmids), mobilization of resistance elements (ompK35 inactivation by ISEcp1-bla CTX-M-15 mobilization, varying numbers of resistance genes on plasmid scaffolds) and chromosomal mutations (mutations in mgrB) leading to further antibiotic resistance that coincided with antibiotic pressure. Importantly, the HMV strain in this study was unable to preserve the carbapenem-resistant phenotype without the selective pressure of meropenem. Conclusions: To the best of our knowledge, we are the first to report a carbapenem-resistant HMV K. pneumoniae strain in the USA. Ultimately, this case demonstrates the role of antibiotic pressure in the acquisition and loss of important genetic elements.

Original languageEnglish (US)
Pages (from-to)1796-1803
Number of pages8
JournalJournal of Antimicrobial Chemotherapy
Issue number7
StatePublished - Jul 1 2018

ASJC Scopus subject areas

  • Microbiology (medical)
  • Pharmacology (medical)
  • Infectious Diseases
  • Pharmacology


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