Bertran i Forga, Xavier, Hong, Yaoqin, Fairfull-Smith, Kathryn E., Qin, Jilong, and Totsika, Makrina (2025) Nitric oxide donor sodium nitroprusside serves as a source of iron supporting Pseudomonas aeruginosa growth and biofilm formation. Microbiology Spectrum, 13 (10).

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Abstract

Biofilm dispersal agents, like nitric oxide (NO), restore antimicrobial effectiveness against biofilm infections by inducing bacteria to shift from a biofilm to a planktonic state, thereby overcoming the antimicrobial tolerance typically associated with biofilms. Sodium nitroprusside (SNP) is a widely used NO donor for investigating the molecular mechanisms underlying NO-mediated biofilm dispersal in the nosocomial pathogen Pseudomonas aeruginosa. However, the biofilm effects of SNP are variable depending on the in vitro experimental conditions, with some studies reporting enhanced growth in both planktonic and biofilm forms instead of dispersal. These discrepancies suggest that SNP affects P. aeruginosa biofilm-residing cells beyond the release of NO. In this study, we compared SNP with another NO donor, Spermine NONOate, to systematically contrast their effects on biofilm and planktonic cultures of P. aeruginosa. We found that SNP, but not Spermine NONOate, increased the biomass of P. aeruginosa biofilms in microplate cultures. This effect was also observed when biofilm cultures were supplemented with iron. Additionally, supplementation with SNP rescued the planktonic growth of P. aeruginosa in iron-depleted media similarly to FeSO₄, suggesting that SNP may serve as an iron source. Our findings indicate that the use of SNP as an NO donor in biofilm dispersal may be compromised by its role in promoting both biofilm and planktonic growth through its iron center. Our study cautions investigators using SNP for studying NO-mediated biofilm dispersal.

Item ID:	89051
Item Type:	Article (Research - C1)
ISSN:	2165-0497
Copyright Information:	Copyright © 2025 Bertran i Forga et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.
Funders:	Australian Research Council (ARC)
Projects and Grants:	ARC project grant (DP210101317)
Date Deposited:	08 Oct 2025 00:21
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