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Microbiology Society logo Microbiology

Volume 171, Issue 11

Rapid accumulation of fluorophores and fast kill identify drugs with bactericidal effects against Gram-negative bacteria Open Access

Abstract

Antimicrobial resistance is a massive threat, but developing a new antibiotic can take decades. That time could be drastically reduced if we were able to anticipate desirable properties of a chemical, such as its potential to target specific bacterial compartments. This would provide the opportunity to prioritize the development of molecules that target, for instance, the cell membrane, as this does not rely on transporters and usually results in a fast-acting bactericidal effect. We used flow cytometry and a set of fluorophores together with a group of antibiotics to discriminate between antimicrobials acting on cell membrane versus intracellularly against two Gram-negative bacteria, and . We then chose Rhodamine 123 as a fluorescent marker to screen a commercial library of chemical compounds. Using flow cytometry, several drugs present in the Prestwick library were observed to have cytotoxic effects at 1 µM final concentration towards . This was confirmed with growth inhibitory assays in both and for pantoprazole, theophylline and zoledronic acid. This represents an approach to the large-scale screening of small molecules with the potential to deliver fast-acting molecules that target cell membranes in Gram-negative bacteria.

  • Received:
  • Accepted:
  • Published Online:
Keyword(s): A. baylyi , antibiotics , cell membrane , E. coli , flow cytometry , fluorophores , Gram-negative , polymyxins and Prestwick library
Funding
This study was supported by the:
  • Novo Nordisk DK (Award NNF20CC0035580)
    • Principal Award Recipient: DouglasBruce Kell
© 2025 The Authors
  • This is an open-access article distributed under the terms of the Creative Commons Attribution License. This article was made open access via a Publish and Read agreement between the Microbiology Society and the corresponding author’s institution.
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2025-11-13
2025-12-16

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/content/journal/micro/10.1099/mic.0.001619
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Rapid accumulation of fluorophores and fast kill identify drugs with bactericidal effects against Gram-negative bacteria
Microbiology 171, 001619 (2025); https://doi.org/10.1099/mic.0.001619
/content/journal/micro/10.1099/mic.0.001619
/content/journal/micro/10.1099/mic.0.001619
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