Antibiotic-producing microorganisms: taxonomic diversity, screening strategies, and emerging and underexploited antibacterial targets.

The discovery of antibiotics revolutionized modern medicine, but the escalating threat of antimicrobial resistance (AMR) now severely compromises treatment efficacy. This review critically examines the diversity of antibiotic-producing microorganisms, with particular emphasis on strains isolated from extreme and underexplored ecological niches, and discusses how microbial interactions influence antibiotic biosynthesis. We summarize recent technological advances that have accelerated antibiotic discovery, including genome mining, innovative cultivation strategies, co-culture systems, and microfluidic platforms. Furthermore, we distinguish established antibacterial targets from emerging or noncanonical ones and evaluate them in terms of mechanistic validation, resistance liability, druggability, and translational relevance, encompassing cell wall precursor Lipid II, division protein FtsZ, epigenetic regulators, cytoskeletal MreB, peptidoglycan and Lipid A biosynthetic enzymes, DNA gyrase, topoisomerase IV, aminoacyl-tRNA synthetases, efflux pumps, and ATP synthase. We further discuss emerging antibacterial strategies, including multi-target mechanisms and resistance-informed target prioritization, as complementary approaches to limiting resistance evolution. Looking forward, we propose an integrated framework that unites three strategic priorities: harnessing untapped microbial resources, establishing high-efficiency screening pipelines, and advancing targeted biosynthetic engineering alongside validation of emerging and underexploited antibacterial targets. Within this framework, multi-target strategies are discussed as one potential approach to reduce resistance liability. Collectively, this integrated approach will facilitate a more focused R&D agenda, providing both a technical blueprint and strategic guidance for the development of next-generation antibiotics.