Morpholino oligomers tested in vitro, in biofilm and in vivo against multidrug-resistant Klebsiella pneumoniae

Bruce L. Geller, Lixin Li, Fabian Martinez, Erin Sully, Carolyn R. Sturge, Seth M. Daly, Christine Pybus, David E. Greenberg

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Background: Klebsiella pneumoniae is an opportunistic pathogen and many strains are multidrug resistant. KPC is one of the most problematic resistance mechanisms, as it confers resistance to most β-lactams, including carbapenems. A promising platform technology for treating infections caused by MDR pathogens is the nucleic acid-like synthetic oligomers that silence bacterial gene expression by an antisense mechanism. Objectives: To test a peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) in a mouse model of K. pneumoniae infection. Methods: PPMOs were designed to target various essential genes of K. pneumoniae and screened in vitro against a panel of diverse strains. The most potent PPMOs were further tested for their bactericidal effects in broth cultures and in established biofilms. Finally, a PPMO was used to treat mice infected with a KPC-expressing strain. Results: The most potent PPMOs targeted acpP, rpmB and ftsZ and had MIC75s of 0.5, 4 and 4 lM, respectively. AcpP PPMOs were bactericidal at 1-2×MIC and reduced viable cells and biofilm mass in established biofilms. In a mouse pneumonia model, therapeutic intranasal treatment with ~30 mg/kg AcpP PPMO improved survival by 89% and reduced bacterial burden in the lung by ~3 logs. Survival was proportional to the dose of AcpP PPMO. Delaying treatment by 2, 8 or 24 h post-infection improved survival compared with control groups treated with PBS or scrambled sequence (Scr) PPMOs. Conclusions: PPMOs have the potential to be effective therapeutic agents against KPC-expressing, MDR K. pneumoniae.

Original languageEnglish (US)
Pages (from-to)1611-1619
Number of pages9
JournalJournal of Antimicrobial Chemotherapy
Issue number6
StatePublished - Jun 1 2018

ASJC Scopus subject areas

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


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