Mechanistic insights into the antimicrobial effect of benzodioxane-benzamides against Escherichia coli

first_page settings Order Article Reprints Open AccessArticle Mechanistic Insights into the Antimicrobial Effect of Benzodioxane-Benzamides Against Escherichia coli by Lorenzo Suigo 1 [ORCID] , Alessia Lanzini 2 [ORCID] , Valentina Straniero 2 [ORCID] and William Margolin 1,* [ORCID] 1 Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas, Houston, TX 77030, USA 2 Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Luigi Mangiagalli, 25, 20133 Milano, Italy * Author to whom correspondence should be addressed. Antibiotics 2026, 15(2), 126; https://doi.org/10.3390/antibiotics15020126 Submission received: 15 December 2025 / Revised: 22 January 2026 / Accepted: 23 January 2026 / Published: 27 January 2026 (This article belongs to the Section Genetic and Biochemical Studies of Antibiotic Activity and Resistance) Download keyboard_arrow_down Browse Figures Versions Notes Abstract Background/Objectives: The bacterial cell division machinery is emerging as an attractive target for antimicrobial compounds. FtsZ, a highly conserved essential division protein, is the target for a number of small molecules such as benzamides. Recent studies show that benzodioxane-benzamides (BDOBs) are among the most potent inhibitors of FtsZ function in Gram-positive bacteria, although their ability to inhibit Gram-negative FtsZ, in particular Escherichia coli FtsZ, has been more controversial. Methods: Here, we use genetic and cytological methods to demonstrate that FtsZ of efflux pump-disabled E. coli can be efficiently targeted by BDOBs. Results: We show that engineered mutants and spontaneous variants map in or near the interdomain cleft (IDC) of FtsZ that confers resistance to BDOBs, similar to previous results with Gram-positive FtsZs. We also uncover spontaneous extragenic mutants that can confer high levels of resistance to at least one potent BDOB, including a mutant that encodes a novel hyperfission variant of the essential cell division protein FtsW. Conclusions: Our evidence indicates that as with Gram-positive bacteria, the IDC of Gram-negative bacterial FtsZ is directly targeted by BDOBs, provided efflux pumps are disabled. We also conclude that FtsZ-independent factors can influence the effect of BDOBs on E. coli cell division, including activation of division septum synthesis.