Multidrug-resistant (MDR) bacteria pose a major threat to public health, and additional sources of antibacterial candidates are urgently needed. Noncanonical peptides (NCPs), derived from noncanonical small open reading frames, represent small biological molecules with important roles in biology. However, the antibacterial activity of NCPs remains largely unknown. Here, we discovered a plant-derived noncanonical antibacterial peptide (NCBP1) against both Gram-positive and Gram-negative bacteria. NCBP1 is composed of 11 amino acid residues with cationic surface potential and favorable safety and stability. Mechanistic studies revealed that NCBP1 displayed antibacterial activity by targeting phosphatidylglycerol and cardiolipin in bacterial membrane, resulting in membrane damage and dysfunction. Notably, NCBP1 showed promising efficacy in mice. Furthermore, NCBP1 effectively inhibited the growth of plant fungal pathogens and enhanced disease resistance in maize. Our results demonstrate the unexplored antimicrobial potential of plant-derived NCPs and provide an accessible source for the discovery of antimicrobial substances against MDR bacterial and fungal pathogens.

The rise in antibiotic-resistant bacteria highlights the need for novel antimicrobial agents. This study presents the design and synthesis of a series of rhein (RH)-derived compounds with improved antimicrobial properties. The lead compound, RH17, exhibited a potent antibacterial activity against Staphylococcus aureus (S. aureus) isolates, with minimum inhibitory concentrations (MICs) ranging from 8 to 16 μg/mL. RH17 disrupted bacterial membrane stability, hindered metabolic processes, and led to an increase in reactive oxygen species (ROS) production. These mechanisms were confirmed through bacterial growth inhibition assays, membrane function assessments, and ROS detection. Notably, RH17 outperformed the parent compound RH and demonstrated bactericidal effects in S. aureus. The findings suggest that RH17 is a promising candidate for further development as an antimicrobial agent against Gram-positive pathogens, addressing the urgent need for new therapies.

Bacterial infections have posed a serious threat globally. The discovery of new targets and the development of novel antimicrobial agents are urgently needed to combat these bacterial infections. The bacterial membrane is a dynamic and essential structure that not only fortifies cellular integrity but also maintains bacterial core metabolism and environmental adaptation. Phospholipids constitute the primary building blocks of the bacterial membrane. The structural variability of phospholipids in both their head groups and acyl chains enables them to dynamically adjust the membrane's biophysical characteristics such as fluidity, curvature and surface charge, thereby directly shaping membrane functionality. In bacteria, these chemo-diverse phospholipids are tightly controlled by their conserved biosynthetic pathways. In this review, we summarize the structural diversity of bacterial phospholipids and their physicochemical implications, describe the biosynthesis and modification mechanisms, and discuss the critical roles of phospholipid diversity in bacterial stress adaptation and antibiotic resistance. Moreover, we highlight emerging antimicrobial strategies that directly target bacterial phospholipids or inhibit key enzymes in phospholipid biosynthetic pathways. These findings will shed light on the discovery of antibacterial targets to develop novel antibacterial agents.

Background/Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) presents a major public health challenge due to its multidrug resistance and high virulence. Developing representative model strains is crucial for systematically assessing pathogenesis and antimicrobial therapies. Methods: The highly virulent MRSA strain T144, isolated from pigs, was characterized through whole-genome sequencing and antimicrobial susceptibility testing. Infection models were successfully established in Galleria mellonella and mice to evaluate virulence. A mouse lung infection model was specifically developed to assess bacterial load dynamics, immune responses, and the efficacy of vancomycin treatment. Results: MRSA T144 demonstrated broad-spectrum antibiotic resistance and high mortality rates in both Galleria mellonella and mouse models. Whole-genome sequencing identified multiple virulence-associated genes, including hemolysins and enterotoxins. The concentration of 7 × 10⁸ CFUs was optimized for establishing the mouse lung infection model. In the mouse lung infection model, MRSA T144 demonstrated rapid bacterial proliferation within the first 24 h, followed by a slower growth rate. Significant changes in immune markers were observed, with elevated levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IL-17a, TNF-α) and decreased IL-10 levels. Vancomycin treatment significantly improved survival rates and reduced bacterial load, confirming the model’s utility for antimicrobial efficacy studies. Conclusions: The successful establishment of MRSA T144 infection models provides a robust platform for investigating bacterial dynamics, immune responses, and antimicrobial efficacy against highly virulent MRSA strains. These findings highlight the potential of MRSA T144 as a valuable model for developing novel therapeutic strategies.

A novel antibacterial agent, TTCVP, selectively targets bacterial inner membranes by binding to phospholipid fatty acid side chains. It disrupts the proton motive force, induces intracellular ROS accumulation, and ultimately leads to bacterial death.

Background: Fungal infections pose an increasingly predominant threat to human and animal health. Modified compounds derived from chemo-diverse natural products offer enhanced therapeutic efficacies and promising approaches to combat life-threatening fungal pathogens. Methods: We performed biosynthetic gene clusters analysis of 2,4-diacetylchloroglucoside (DAPG) in 4292 shotgun metagenomes samples from the healthy and diseased skin. Then, we assessed the antifungal activity of DAPG and the derivative 2,4-diproylphloroglucinol (DPPG) against pathogenic fungi by minimum inhibitory concentrations. The inhibitory effects of DPPG were measured using hyphal growth assay and spore germination assay. Concurrently, the mechanism of DPPG on Aspergillus fumigatus was investigated in membrane permeability and fluidity. The therapeutic efficacy was evaluated in a Galleria mellonella infection model. Results: We observed a significantly higher abundance of bacteria harboring DAPG biosynthetic clusters on healthy skin compared to diseased skin. Further, we designed and synthesized a series of phloroglucinol derivatives based on DAPG and obtained an antifungal candidate DPPG. DPPG not only exhibited robust antifungal activity against Aspergillus spp. and Candida spp. but also impaired hyphal growth and spore germination of A. fumigatus in vitro. A mechanism study showed that DPPG reduced membrane fluidity and increased the leakage of cellular contents, resulting in membrane perturbation and fungal death. Lastly, the therapeutic efficacy of DPPG was confirmed in a G. mellonella infection model. Conclusions: Our study demonstrates that DPPG is a potent scaffold to combat invasive fungal infections.