ACS Infectious Diseases最新文献

Lateral flow immunoassays (LFIAs) are widely used point-of-care (POC) diagnostic tools, but their limited sensitivity can hinder reliable diagnoses. To address this limitation, we developed a novel POC diagnostic platform for the highly sensitive detection of influenza A virus (IAV). This developed platform integrates platinum nanoparticle–catalyzed 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation for reagent-free, single-step signal amplification with smartphone-based image acquisition and quantitative analysis. This combination of catalytic enhancement and digital interpretation enables rapid, objective, and quantitative diagnostic evaluation, offering improved performance over conventional LFIAs. Upon sample application, the sample flows to complete the immunoreaction at the test line, followed by a chromatographically delayed acidic migration that rehydrates the TMB and delivers it to the captured platinum nanoparticles for signal amplification. This reagent-free, timed enhancement results in approximately 100-fold visual signal amplification compared to unenhanced detection, without the need for additional reagents. Additionally, a custom-developed smartphone application automates image acquisition and quantifies intensity ratios to provide the final diagnosis. The platform achieves a limit of detection of 11.6 pg/mL IAV nucleoprotein within 15 min, offering a 1000-fold increase in sensitivity over traditional LFIAs. In clinical trials, it demonstrated excellent performance, with 96.8% sensitivity and 98.4% specificity compared to RT-PCR. The platform also exhibited semiquantitative capability, with a strong inverse correlation (R² = 0.832) between RT-PCR Ct values and intensity ratios. This integrated system provides a rapid, low-cost, and user-friendly solution for accurate viral diagnostics.

Infectious diseases remain a serious global health threat due to their high transmissibility and mortality, highlighting the urgent need for sensitive and rapid diagnostic tools to enable early detection and effective intervention. Herein, we report an ultrasensitive biosensing platform that integrates Fe₃O₄@UiO-66-NH₂ nanocomposites with a graphene field-effect transistor (GFET) for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The nanocomposites were conjugated with antibodies against SARS-CoV-2, enabling selective capture of viral particles from complex biological matrices. Following magnetic enrichment, the GFET sensor was employed for signal transduction and quantitative analysis. The platform demonstrated a broad dynamic range (1 ag·mL^–1 to 10 ng·mL^–1) with an exceptionally low detection limit of 1.98 ag·mL^–1. Furthermore, successful detection of SARS-CoV-2 antigens in serum samples highlights its potential for point-of-care and real-time diagnostic.

Acinetobacter baumannii, a Gram-negative WHO critical priority pathogen, is an opportunistic bacterial pathogen associated with increasing hospital- and community-acquired infections. The emergence of a multidrug-resistant pathogen, especially the carbapenem-resistant A. baumannii (CRAB), has left us with extremely limited treatment options and, consequently, very high morbidity and mortality rates. As per WHO, the transmissibility of A. baumannii is considered between moderate to high. This review provides a unique comprehensive insight into pathogen’s global epidemiology, pathogenesis, host–pathogen interaction, tools to study the pathogen, associated diseases, available treatment options, and how the pathogen is becoming resistant to almost all the treatment options available, thus presenting a holistic picture.

The surging crisis of multidrug-resistant Gram-negative pathogens underscores the urgent need for antibiotics with novel mechanisms of action. A promising strategy is to target previously unexploited pathways, such as lipid A biosynthesis. Lipid A functions as the membrane anchor of lipopolysaccharide and constitutes the outer monolayer of the outer membrane of Gram-negative bacteria. LpxH, a Mn²⁺-dependent phosphoesterase, catalyzes the conversion of UDP-2,3-diacylglucosamine to lipid X, a key precursor in lipid A production. Disruption of this essential step compromises outer membrane integrity, leading to bacterial death, making LpxH an attractive antibiotic target. Since AstraZeneca’s discovery of the first small-molecule LpxH inhibitor a decade ago, research has progressed substantially. The development of nonradioactive LpxH activity assays has enabled rapid screening and characterization of inhibitors. Structural and biochemical studies have revealed the architecture of LpxH and dynamic properties of the bound inhibitors, informing structure- and dynamics-based inhibitor design. Notably, recent breakthroughs from academic institutions and pharmaceutical companies have produced LpxH inhibitors with potent antibacterial activity against wild-type Enterobacterales in both in vitro and in vivo models. This review describes the biological role of LpxH and its paralogs, highlights recent advances in assay development and structural analysis, and surveys the current landscape of LpxH-targeting compounds in preclinical development. These collective advances establish LpxH as a novel target in the battle against multidrug-resistant Gram-negative infections and highlight a promising therapeutic opportunity that could reinvigorate the antibiotic pipeline.

The rise of difficult-to-treat Mycobacterium abscessus infections presents a growing clinical challenge due to the immense arsenal of intrinsic, inducible and acquired antibiotic resistance mechanisms that render many existing antibiotics ineffective against this pathogen. Moreover, the limited success in discovery of novel compounds that inhibit novel pathways underscores the need for innovative drug discovery strategies. Here, we report a strategic advancement in PROSPECT (PRimary screening Of Strains to Prioritize Expanded Chemistry and Targets), which is an antimicrobial discovery strategy that measures chemical–genetic interactions between small molecules and a pool of bacterial mutants, each depleted of a different essential protein target, to identify whole-cell active compounds with high sensitivity. Applying this modified strategy to M. abscessus, in contrast to previously described versions of PROSPECT which utilized protein degradation or promoter replacement strategies for generating engineered hypomorphic strains, here we leveraged CRISPR interference (CRISPRi) to more efficiently generate mutants each depleted of a different essential gene involved in cell wall synthesis or located at the bacterial surface. We applied this platform to perform a pooled PROSPECT pilot screen of a library of 782 compounds using CRISPRi guides as mutant barcodes. We identified a range of active hits, including compounds targeting InhA, a well-known mycobacterial target but under-explored in the M. abscessus space. The unexpected susceptibility to isoniazid, traditionally considered to be ineffective in M. abscessus, suggested a complex interplay of several intrinsic resistance mechanisms. While further complementary efforts will be needed to change the landscape of therapeutic options for M. abscessus, we propose that PROSPECT with CRISPRi engineering provides an increasingly accessible, high-throughput target-based phenotypic screening platform and thus represents an important step toward accelerating early stage drug discovery.

Tuberculosis (TB) remains the world’s deadliest bacterial infection, with 8.2 million newly notified cases and an estimated 1.25 million deaths in 2023. Alarmingly, ∼19% of multidrug- or rifampicin-resistant (MDR/RR) strains already meet the World Health Organization (WHO) definition of pre-XDR-TB because they are resistant to at least one fluoroquinolone (FQ). Although gyrA/gyrB target-site mutations dominate clinical FQ resistance, Mycobacteria also rely on transcriptional networks that help them withstand the oxidative and DNA strand-breaking stress caused by these drugs. Central to this response is the heterodimeric transcription factor pafBC, whose WYL domain binds to single-stranded DNA and redirects RNA polymerase to a dedicated promoter set, thereby orchestrating a LexA-independent DNA-damage response (DDR). Up-regulation of pafBC has been linked to enhanced intracellular survival of M. tuberculosis and nontuberculous mycobacteria after FQ exposure, yet the downstream phenotypes and their connection to drug or phage resistance have remained unclear. Here, we demonstrate that deletion of pafBC in Mycobacterium smegmatis profoundly remodels the cell envelope, as evidenced by altered colony rugosity, reduced sliding motility, enhanced aggregation, and a three- to 5-fold decline in quantitative biofilm biomass. Untargeted lipid profiling revealed the selective depletion of long-chain trehalose polyphosphates and other apolar glycolipids that normally decorate the outer membrane─lipid classes that have recently been shown in other studies to serve as essential receptors for therapeutic mycobacteriophages such as BPs and Muddy. Consistent with this lipid deficit, the pafBC mutant exhibited markedly reduced phage adsorption and plaque formation; ectopic expression of RecA restored adsorption efficiency, implicating DDR envelope crosstalk in antiphage defense. Complementation with wild-type pafBC rescued lipid composition, biofilm mass, and phage resistance, whereas a WYL-domain mutant that cannot bind single-stranded DNA failed to do so, underscoring the necessity of canonical pafBC activation for envelope homeostasis. Immunoprofiling in THP-1 macrophages further showed that pafBC-proficient bacilli induce significantly higher secretion of IL-1β, TNF-α, and IL-6 compared to their isogenic mutant. This effect correlated with the presence of intact surface glycolipids, molecules known to interact with scavenger and Toll-like receptors on phagocytes and to enhance opsonizing antibody deposition at the host–pathogen interface. Overall, our findings connect the molecular mechanisms of the pafBC DDR with observable phenotypes such as fluoroquinolone tolerance, biofilm structure, phage resistance, and host immune recognition, by highlighting cell-envelope remodeling as the central factor.

The host microbiome plays a crucial protective role against pathogenic infections, not only through direct competition with invading pathogens but also by coordinating host antimicrobial and barrier functions and educating immune cells. While essential for pathogen clearance, unchecked, prolonged, or excessive inflammation from host immune responses can paradoxically lead to serious consequences for the host including the development of chronic inflammatory and autoimmune diseases. Recent research highlights how microbiome disruptions can exacerbate infection-associated inflammation and pathology. Even with established links among microbes, inflammation, and infection susceptibility, a comprehensive understanding of the cellular and molecular mechanisms connecting the microbiome’s role in resolving infection-associated inflammation remains largely undefined. This review discusses our current understanding of the microbiome’s contribution to resolving inflammation and tissue damage postinfection and its potential impact on therapeutic approaches for alleviating infection-induced inflammatory diseases.

Herein, we describe the design, synthesis, and evaluation of modified cyclic peptides based upon the privileged structure of the cyclic depsipeptide natural products, ohmyungsamycin and ecumicin, that target Mycobacterium tuberculosis (Mtb) caseinolytic-like protein 1 (ClpC1). Simplified analogues featuring substitution at three sites (l-Thr-3, N-Me-l-Trp-9, and/or the N-terminus) were designed and synthesized via a novel and robust strategy, employing an oxazolidine-protected C-terminal amino acid, to enable late-stage, epimerization-free, solution-phase macrolactamization. Lead analogues had nanomolar affinity for the ClpC1 N-terminal domain (NTD), possessed potent activity against Mtb in vitro and were shown to inhibit protein degradation by the mycobacterial ClpC1:ClpP1P2 protease with an associated enhancement of ClpC1 ATPase activity. The most promising analogue from the series exhibited prolonged bactericidal killing activity against Mtb without the emergence of resistance and retained activity in an in vivo zebrafish model of mycobacterial infection.

The combination of an antibiotic with a metabolic reprogramming agent is anticipated to emerge as a promising therapeutic strategy against antibiotic-resistant bacteria, although this hypothesis requires validation through preclinical pharmacodynamic studies. This study evaluated the preclinical pharmacodynamic profile of cefoperazone-sulbactam (SCF) combined with glutamine against 237 Acinetobacter baumannii clinical isolates, including 26 antibiotic-sensitive (S-AB), 8 multidrug-resistant (MDR-AB), and 203 carbapenem-resistant strains (CR-AB). The combination demonstrated synergistic efficacy in 224 cases (94.51%), equivalence in 10 (4.22%), and no interaction in 3 (1.27%) compared with SCF monotherapy. Time-kill assays, bacterial load quantification, and murine infection models consistently validated these findings, with therapeutic effects remaining stable despite variations in calcium concentrations and pH gradients. Glutamine slows the development of SCF resistance, prolongs the postantibiotic effect, and reduces mutation frequency. Mechanistically, glutamine reprograms bacterial metabolism from an antibiotic-resistant state to an antibiotic-sensitive state, thereby enhancing reactive oxygen species (ROS) production, which combines with increased drug uptake to potentiate SCF killing. This accelerated drug influx surpasses the clearance capacity mediated by efflux pumps and enzymatic degradation, resulting in increased bacterial eradication through synergy with ROS. These findings suggest that the synergistic combination holds the potential for developing therapeutic candidates against MDR-AB and CR-AB.

Dihydropteroate synthase (DHPS) is a critical enzyme in the folate biosynthetic pathway of bacteria, fungi, and protozoans. Sulfonamides successfully target the p-aminobenzoic acid (pABA) binding site of DHPS, forming a false product that obstructs the formation of 7,8-dihydropteroate and disrupts subsequent reactions in the pathway. Pyrimido[4,5-c]pyridazine-based inhibitors target the pterin binding site of DHPS, demonstrating high target affinity but minimal antimicrobial activity, which has previously been attributed to poor permeability without detailed analysis. In this study, we investigate the permeability limitations of our pyrimido pyridazine series in Gram-negative bacteria within the context of whole cell target engagement and cellular accumulation. To evaluate their whole cell target engagement against Escherichia coli DHPS (EcDHPS), we developed a robust luminescence-based HiBiT cellular thermal shift assay and combined it with surface plasmon resonance and an LC-MS/MS-based accumulation assay. This orthogonal assay platform was used to reevaluate the SAR of our Legacy pyrimido pyridazine compound series against EcDHPS and to facilitate the design of an exploratory series of compounds with improved permeability. From this series, we found that the removal or replacement of the negatively charged carboxylic acid pyrimido pyridazine side chain with a thiotetrazole or a nitrile group resulted in increased accumulation, improved whole cell target engagement, and moderate antimicrobial activity against E. coli.