A high-throughput, whole cell assay to identify compounds active against carbapenem-resistant Klebsiella pneumoniae

PLoS One. 2018 Dec 21;13(12):e0209389. doi: 10.1371/journal.pone.0209389. eCollection 2018.

Abstract

Enteric Gram-negative rods (GNR), which are frequent causes of community-acquired and nosocomial infections, are increasingly resistant to the antibiotics in our current armamentarium. One solution to this medical dilemma is the development of novel classes of antimicrobial compounds. Here we report the development of a robust, whole cell-based, high-throughput metabolic assay that detects compounds with activity against carbapenem-resistant Klebsiella pneumoniae. We have used this assay to screen approximately 8,000 fungal extracts and 50,000 synthetic compounds with the goal of identifying extracts and compounds active against a highly resistant strain of Klebsiella pneumoniae. The primary screen identified 43 active fungal extracts and 144 active synthetic compounds. Patulin, a known fungal metabolite and inhibitor of bacterial quorum sensing and alanine racemase, was identified as the active component in the most potent fungal extracts. We did not study patulin further due to previously published evidence of toxicity. Three synthetic compounds termed O06, C17, and N08 were chosen for further study. Compound O06 did not have significant antibacterial activity but rather interfered with sugar metabolism, while compound C17 had only moderate activity against GNRs. Compound N08 was active against several resistant GNRs and showed minimal toxicity to mammalian cells. Preliminary studies suggested that it interferes with protein expression. However, its direct application may be limited by susceptibility to efflux and a tendency to form aggregates in aqueous media. Rapid screening of 58,000 test samples with identification of several compounds that act on CR-K. pneumoniae demonstrates the utility of this screen for the discovery of drugs active against this highly resistant GNR.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / isolation & purification
  • Anti-Bacterial Agents / pharmacology*
  • Anti-Bacterial Agents / therapeutic use
  • Carbapenems / pharmacology
  • Carbapenems / therapeutic use
  • Drug Discovery / methods
  • Drug Resistance, Multiple, Bacterial
  • Fungi / metabolism*
  • High-Throughput Screening Assays / methods*
  • Humans
  • Klebsiella Infections / drug therapy*
  • Klebsiella Infections / microbiology
  • Klebsiella pneumoniae / drug effects*
  • Klebsiella pneumoniae / physiology
  • Microbial Sensitivity Tests / methods

Substances

  • Anti-Bacterial Agents
  • Carbapenems

Grant support

This work was funded by the a Boston Childrens Hospital technology development fund grant to PIW. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.