ACS Infectious Diseases最新文献

The escalating global crisis of antibiotic resistance demands the urgent development of innovative antibacterial agents with new mechanisms of action. Herein, we report the design and characterization of self-derived antibacterial peptides from the N-terminal region of Escherichia coli OmpF, a typical β-barrel outer membrane protein (OMP). These peptides exhibit cellular lethality when endogenously expressed, and one of them, having 42 amino acids in length (designated as OmpF7), directly kills outer membrane-permeabilized E. coli cells. Mechanistically, OmpF7 interacts with periplasmic chaperones SurA and Skp in vitro, disrupts both in vitro and in vivo SurA–OmpF interactions, decreases the level of folded OmpF, and severely influences cell morphology but has little detrimental effect on the cytoplasmic membrane and behaves distinctively from polymyxin B, a well-known antibacterial peptide. Importantly, OmpF7 directly kills Gram-negative pathogens (e.g., Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and Salmonella typhimurium) and multidrug-resistant clinical isolates of E. coli when it is conjugated with a membrane-penetrating peptide or combined with a nontoxic adjuvant carvacrol. These observations suggest that OmpF7 exerts its lethal effects by saturating the OMP-binding sites of SurA/Skp and thus disrupting chaperone-mediated OMP biogenesis, eventually leading to cell death. Our study not only validates periplasmic chaperone–OMP interactions as promising drug targets against Gram-negative pathogens but also provides a chemical biology tool for probing the OMP biogenesis mechanism.

Intracellular bacterial infections remain a global health challenge due to their insidious and persistent nature. This review focuses on host–pathogen interactions, referring to the dynamic struggle between host immune defenses and bacterial invasion/survival mechanisms. A thorough understanding of host cell bactericidal mechanisms, as well as the invasion and evasion strategies employed by intracellular bacteria, is essential for developing novel antibacterial agents. Crucially, traditional antibiotics often fail due to poor membrane permeability, rapid efflux, or suboptimal subcellular accumulation, leading to treatment failure and resistance. To break this deadlock, peptide-based therapeutics offer a transformative frontier through: (1) precision delivery via cell-penetrating peptides (CPPs); (2) multimodal bactericidal mechanisms to minimize resistance; and (3) host-directed therapies that reactivate innate defense pathways. Furthermore, we highlight optimization strategies ranging from rational chemical design to AI-driven generative discovery. To facilitate clinical translation, we conclude by outlining future directions: integrating ultralarge library screening (e.g., phage/mRNA display) to expand discovery; employing chemical modifications and nanoencapsulation to overcome metabolic fragility; and developing stimuli-responsive “smart” platforms for spatiotemporally precise, low-toxicity delivery. Finally, implementing compartment-specific PK/PD models to quantify subcellular drug exposure is essential.

The interactions among the host’s circular RNAs (circRNAs), microRNAs (miRNAs), and target genes are crucial for antibacterial resistance and intracellular pathogen clearance. However, this process remains poorly understood during Mycobacterium tuberculosis (M.tb) infection. Our previous study identified hsa_circ_000477, a novel circRNA formed by the NRIP1 gene on human chromosome 21, which was upregulated in M.tb-infected THP-1 macrophages. The present study systematically investigated the effect of hsa_circ_0004771 on M.tb infection and the underlying molecular mechanism. First, hsa_circ_0004771 was demonstrated to inhibit M.tb intracellular survival in macrophages. To identify its target miRNAs, multiple algorithms were used for computational prediction, and qPCR, dual-luciferase reporter assays, and RNA fluorescence in situ hybridization (FISH) were performed to confirm that miR-3921 was the primary target miRNA of hsa_circ_0004771. Further computational analyses across multiple algorithms─such as miRDB, TarBase, TargetScan, and microT-CDS─and validation with the above-mentioned methods, TREM1 was identified as the target of miR-3921. The results showed that an elevated level of TREM1 expression increased P65 phosphorylation levels, thereby enhancing IL-1β secretion. In conclusion, we identified a novel host defense mechanism in M.tb-infected THP-1 cells: the hsa_circ_0004771/miR-3921/TREM1 axis suppresses bacterial survival by promoting proinflammatory IL-1β production. These findings revealed a novel mechanism involved in host defense against M.tb infection.

Coxsackievirus A6 (CVA6) is the most common causative pathogen of hand, foot, and mouth disease (HFMD) in children under 5 years of age and has caused multiple outbreaks in recent years. Currently, no effective vaccines or antiviral treatments are available. The present study introduces a detection assay, termed CVA6-RT-MCDA-LFB, which combines reverse transcription multiple cross displacement amplification (RT-MCDA) with a nanoparticle-based lateral flow biosensor (LFB). Ten specific primers targeting the VP1 gene region were designed for CVA6-RT-MCDA. The assay demonstrated an analytical sensitivity of 33 copies per reaction, with 100% specificity and no cross-reactivity against non-CVA6 strains. Clinical performance was evaluated using 70 anal swab samples and 42 throat swab samples, demonstrating 100% concordance between CVA6-RT-MCDA-LFB and commercial quantitative real-time PCR(qRT-PCR). The entire detection process could be completed within 1 h, including sample preprocessing (15 min), isothermal amplification (40 min), and result confirmation (1–2 min). This rapid turnaround, combined with simplicity and high accuracy, makes CVA6-RT-MCDA-LFB a promising Point-of-Care Testing (POCT) for CVA6, particularly in resource-limited settings.

Klebsiella pneumoniae poses a substantial health concern worldwide, with high mortality often associated with its elevated resistance levels. Combination antibiotic therapies have emerged as a viable strategy for addressing infections caused by these highly resistant pathogens, yet the evolutionary routes to resistance under such regimens remain poorly understood. Here, we investigated how resistance can emerge during exposure to combination therapy by conducting an in vitro evolutionary experiment with a clinical K. pneumoniae KPC-producing isolate (KP03, Brazil), which was initially susceptible to both amikacin and polymyxin B (AmkPol). While the combination therapy displayed an additive effect in vitro, subinhibitory exposure rapidly drove resistance. In three independent lineages, bacteria tolerated concentrations nearly 10-fold (polymyxin B) and 5-fold (amikacin) above EuCAST breakpoints, with MICs reaching 128-256 μg·mL^-1 after 45 passages. These high resistance levels persisted for at least 10 days without selective pressure, although resistance lineages exhibited measurable fitness costs. Whole-genome sequencing revealed diverse mutations affecting lapB, phoP, rho, smbA, mlaA, and asmA, while transcriptomics analysis showed upregulation of the arn operon and the aphA alongside with downregulation of envelope- and efflux-associated genes. Cross-resistance was also observed against colistin and certain antimicrobial peptides, raising concern for treatment options beyond the AmkPol combination. Although combination therapy represents an important treatment strategy, our findings demonstrate that K. penumoniae can rapidly evolve stable, high-level resistance under combination therapy, highlighting the need for a deeper understanding of how such regimens influence resistance development and the continued need to develop novel antibiotics strategies.

The phosphonic antibiotic fosfomycin is a bacterial cell wall synthesis inhibitor that targets MurA, the first enzyme in the peptidoglycan pathway. Transporter loss or enzymatic inactivation confers resistance to fosfomycin, but whether the metabolic state of a bacterium influences the efficacy of this antibiotic has not been characterized. Here, we used an Escherichia coli CRISPR interference library targeting 1,515 metabolic genes to identify metabolic activities that influence fosfomycin efficacy. We discovered that knockdowns of ATP synthase and pyruvate kinase genes lead to a regrowth phenotype, whereby cells resume growth after an initial phase of killing. By following up on this phenotype with population analysis profile tests and repeated treatment cycles, we found evidence that a heteroresistant population may promote the evolution of fosfomycin resistance. Whole-genome sequencing of the pykF CRISPRi strain after 24 h of fosfomycin exposure revealed that the acid stress protein-encoding gene ibaG, which is upstream of murA, carries a mutation that confers fosfomycin resistance. Metabolome analysis showed accumulation of the MurA substrate phosphoenolpyruvate in regrowing cells, which may compete with fosfomycin for binding to MurA. Transcriptome analysis provided further insight into the mechanism of cell regrowth, including upregulation of genes encoding cell envelope stress response regulators such as cpxP. These results suggest that the metabolic state can modulate the efficacy of fosfomycin and contribute to resistance evolution.

Pleuromutilin is a natural product with promising therapeutic potential and important applications for antimicrobial drug development. The semisynthetic pleuromutilin derivatives obtained through structural modification of the C-14 side chain exhibit significantly enhanced antibacterial activity and pharmacokinetic properties. These compounds specifically bind to the peptidyl transferase center of the bacterial 50S ribosomal subunit to inhibit protein synthesis. To date, pleuromutilin derivatives have shown efficacy against drug-resistant Gram-positive bacteria, some Gram-negative bacteria, and Mycoplasma. This Perspective systematically summarizes research advances in the structural modification and antibacterial activity of pleuromutilin derivatives, with a focus on breakthrough achievements in enhancing antibacterial potency through innovative side-chain designs from 2015 to 2025. Furthermore, this study highlights future directions for innovative drug development based on pleuromutilin structural modification, offering insights into addressing the global challenge of antibiotic resistance.

Carbapenem-resistant Enterobacteriaceae (CRE) pose a serious global health threat due to the ineffectiveness of conventional antibiotics, highlighting the need for new therapeutic strategies. This study explores the potential of nitazoxanide (NTZ), a clinically approved broad-spectrum antiparasitic drug, functionalized onto gold nanoparticles (AuNPs) as an antibacterial approach against CRE. NTZ_AuNPs were synthesized using a one-pot method, and their antibacterial efficacy was assessed through antimicrobial susceptibility testing, bacterial growth analysis, and electron microscopy. Biosafety was evaluated through hemolysis assays and in vivo murine models. The NTZ_AuNPs showed significant bactericidal activity against CRE, with MICs ranging from 4 to 8 μg/mL, and exhibited favorable biocompatibility. Mechanistic investigations revealed that NTZ_AuNPs disrupt bacterial membranes, enhance outer membrane permeability, and infiltrate the intracellular environment. Additionally, NTZ_AuNPs increase reactive oxygen species (ROS) levels and impair bacterial ATP synthesis, suggesting a dual mechanism involving membrane disruption and oxidative stress. In a mouse model of abdominal infection, NTZ_AuNPs reduced bacterial burden and improved survival rates. These results validate the potential of NTZ_AuNPs as an effective, low-toxicity treatment for CRE infections, offering a promising alternative to traditional antibiotics.

The growing number of bacterial infections and the rise of antibiotic resistance require approaches for antimicrobial development. Peptidoglycan, essential for maintaining the integrity and shape of the bacterial cell wall, is regulated by the coordinated activity of peptidoglycan synthesis and remodeling enzymes. While peptidoglycan synthesis enzymes have served as antibiotic targets for decades, peptidoglycan hydrolases have remained largely underexplored. Here, we review recent advances in the development of small-molecule inhibitors of peptidoglycan hydrolases as antimicrobial targets.

Antimicrobial resistance threatens health, and new agents are needed. Lefamulin is the only approved antibiotic of a new class in two decades. It targets the 50S peptidyl transferase center (PTC). Its efficacy against multidrug-resistant pathogens is limited by anionic envelopes, limiting penetration. We report a charge-anchored pleuromutilin exploiting an electrostatic Trojan horse to breach barriers and engage the ribosome. An N-pyridinium provides a cationic localizer. A two-step mechanism operates. Long-range electrostatics enrich ligands at anionic interfaces and the PTC. Short-range interactions secure high-affinity placement of the tricyclic core. Computer simulations support the occupancy of the activity pocket and the field-guided orientation of the cationic side chain for PNY-6b. Proteomics highlights ribosomal proteins as dominant targets. Cellular assays show biofilm eradication and membrane depolarization. In murine infections, PNY-6b lowers burden and improves survival. Electrostatic complementarity offers a generalizable design principle for targets with electrostatic fields and for pathogens with poor envelope permeability.