Antimicrobial resistance (AMR) poses an ongoing threat to global health, with the number of deaths directly attributable to AMR projected to rise to 8 million. One of the main reasons for the current crisis is the depletion of antibiotic candidates in clinical pipelines. To address this, more preclinical candidates must be advanced into development. However, the scientific challenges and limited economic incentives associated with antibiotic research have further aggravated the situation. Antibiotic hybrids, which combine two antibiotics with different modes of action, have emerged as a promising strategy to overcome AMR and are already being developed for clinical use. This approach takes advantage of the strong selective pressure exerted when two bactericidal agents act simultaneously. Importantly, because hybrids are administered as a single chemical entity, they may offer advantages over conventional combination therapies, such as simplified pharmacokinetics and dosing. Furthermore, since clinically validated antibiotics are used as the building blocks of hybrids, this strategy provides an efficient platform for generating new lead compounds. Recently, the concept of antibiotic hybrids has expanded beyond antibiotic–antibiotic conjugates to include the attachment of functional molecules designed to mitigate the disadvantages of the parent antibiotics. In this review, we summarize the definition of antibiotic hybrids, highlight representative compounds that have entered clinical evaluation, and discuss recent advances in their development.

Antibiotic resistance poses a serious challenge to public health worldwide; however, the development of new antibiotic classes for combating bacterial infections, especially those caused by Gram-negative pathogens, has slowed in recent years. Dual-acting hybrid antibiotics with a metabolically non-cleavable covalent bond represent an emerging strategy for developing novel antibiotic classes to overcome antibiotic resistance. The covalent connection between two antibiotics results in a fixed pharmacokinetic profile of a single molecule and can impede bacterial efflux. However, as most antibiotics do not have membrane-destabilizing activity, the resulting increase in molecular weight by connection of two antibiotics could limit their activity against Gram-negative bacteria, whose outer membrane forms a strong barrier blocking the penetration of high-molecular weight antibiotics. Here, we review recent developments in dual-acting hybrid antibiotics targeting Gram-negative bacteria, with a focus on their antibacterial efficacy. We also discuss combination therapy strategies in which the underlying molecular mechanisms of synergy have been characterized. Finally, we outline future directions for the rational design of hybrid antibiotics against Gram-negative pathogens.

β-Lactam antibiotics marked the beginning of an era of effective and safe treatment for bacterial infections and remain the most widely prescribed antibacterial agents today. However, the emergence of antibiotic-resistant bacteria threatens a return to the pre-antibiotic era. In particular, bacterial expression of β-lactamases inactivating β-lactam antibiotics presents a challenge in antimicrobial therapy. While inhibitors against β-lactamases have been developed to protect the therapeutic efficacy of β-lactam antibiotics, the clinical use of β-lactamase inhibitors is constrained due to their limited inhibition spectrum and the emergence of inhibitor-resistant β-lactamase variants. As an effort to tackle this issue, here we reviewed the structural and mechanistic features of β-lactamases and their FDA-approved inhibitors. Moreover, mutations in clinically isolated β-lactamases that confer resistance against their inhibitors are compiled. The comprehensive overview offered in this review aims to support and stimulate the design of next-generation β-lactamase inhibitors for combating β-lactamase-mediated antibiotic resistance.

Protein quality control systems are increasingly recognized as a critical determinant of bacterial survival and antibiotic tolerance. Conventional antibiotics predominantly target nucleic acids, protein synthesis, or cell wall synthesis, yet bacterial adaptation and resistance emergence remain major challenges. Targeting the bacterial protein quality control machineries including molecular chaperones and proteases offers a promising strategy to overcome these limitations. Recent advances include small molecules and adaptor/degron mimetics that modulate the activities of chaperones and proteases, aggregation-prone peptides (APPs) that induce proteotoxic stress, and bacterial PROTAC (BacPROTAC) strategies that redirect endogenous proteases. Notably, persister and viable-but-non-culturable (VBNC) cells, which tolerate conventional antibiotics, remain susceptible to proteostasis-targeted approaches, thereby enabling killing in both actively dividing and dormant populations. Furthermore, synergistic strategies combining chaperone inhibition or protease activation with conventional antibiotics enhance bactericidal efficacy, suggesting a potential avenue to mitigate antimicrobial resistance. This review summarizes the mechanistic basis, recent developments, and translational potential of proteostasis-centered antibacterial strategies.

The escalating threat of antimicrobial resistance has renewed global interest in peptide-based antibiotics as adaptable and effective alternatives to conventional small molecules. Peptides possess diverse mechanisms of action, high target specificity, and structural flexibility, which collectively limit the emergence of resistance. This review outlines recent advances spanning the discovery, optimization, and application of peptide antibiotics, from their biological origins and structural classifications to emerging strategies involving artificial intelligence, synthetic biology, and modern delivery technologies. Peptide antibiotics can be categorized by origin as natural, semi-synthetic, or fully synthetic, and further organized by structural class such as α-helical, β-sheet, cyclic, and extended forms. They are also grouped by function into membrane-targeted and non-membrane-targeted types. These classification schemes are not only descriptive but also critical for understanding the therapeutic potential of peptides, as each category presents distinct advantages and engineering challenges that influence stability, specificity, and overall clinical performance. Advances in artificial intelligence, synthetic biology, and continuous manufacturing are reshaping how peptide drugs are designed and produced, while innovations in drug delivery systems are addressing critical issues of stability and bioavailability. Together, these developments are laying the foundation for a new generation of peptide-based therapeutics capable of meeting the evolving challenges of antimicrobial resistance.

Ribosomes are essential macromolecular machines that facilitate protein synthesis and have long been recognized as effective targets for antimicrobial agents. While structural differences between prokaryotic and eukaryotic ribosomes form the basis for selective antibiotics against bacteria, similar approaches for developing antifungal agents targeting ribosomes have remained limited due to the high sequence and structural conservation with human ribosomes. However, emerging insights into ribosome homeostasis, including ribosome biogenesis, turnover, and hibernation, have uncovered a set of ribosome-associated proteins whose function is critical yet display greater sequence divergence from their human counterparts. These observations suggest that these regulatory components may represent viable antifungal targets by disrupting fungal proteostasis. The present review aims to explore this developing concept by examining ribosome-associated factors and considering whether short ribosomal protein-derived peptides may eventually serve as druggable molecules for selectively modulating these pathways in fungal pathogens.

Antibiotic resistance has become a critical global health challenge due to the decreased efficacy of existing antibiotics and the emergence of multidrug-resistant pathogens. In particular, the rapid horizontal transfer of resistance genes and the diverse mechanisms by which bacteria acquire resistance have significantly undermined the effectiveness of conventional therapeutic strategies, revealing fundamental limitations in current infectious disease management. In this context, synthetic biology provides a promising framework to overcome the limitations of conventional antibiotics by integrating engineering principles with bioengineering approaches, thereby enabling precise and programmable control of biological processes. These synthetic biology-based approaches offer substantial potential for developing sustainable and highly specific antimicrobial strategies. This review comprehensively examines recent advances in synthetic biology-assisted antimicrobial strategies, including CRISPR-Cas systems, bacteriophage engineering, microbiome engineering, and metabolic engineering-driven antibiotic discovery. Collectively, these approaches represent a precision antimicrobial paradigm that enables selective targeting of resistant bacteria while preserving microbiome homeostasis. These strategies also provide new directions for limiting resistance dissemination and guiding the development of next-generation therapeutics.