Chlamydia psittaci is an obligate intracellular zoonotic pathogen that causes atypical pneumonia. Pyroptosis is a type of regulated cell death mediated by gasdermin-family proteins and plays an important role in the response to intracellular infection. This study investigates whether C. psittaci infection triggers GSDME-mediated pyroptosis through the ROS-JNK signaling pathway. Our study revealed that infection with C. psittaci induces pyroptosis through caspase-3 activation and subsequent GSDME cleavage in human cervical epithelial (HeLa) cells. Mechanistically, the infection increased intracellular levels of reactive oxygen species (ROS) and phosphorylated c-Jun N-terminal kinase (JNK). Treatment with either the ROS scavenger NAC or the JNK inhibitor SP600125 significantly suppressed pyroptosis. Furthermore, inhibition of either the caspase-3-GSDME axis or the ROS-JNK pathway significantly increased the number of C. psittaci inclusion bodies. Taken together, our findings suggest that the ROS/JNK signaling pathway modulates GSDME-mediated pyroptosis and concurrently restricts C. psittaci replication in host cells, identifying the ROS-JNK-GSDME axis as a key mechanism in C. psittaci-induced pyroptosis. These findings reveal novel therapeutic targets for the treatment of psittacosis.

OBJECTIVE:To determine the prevalence, antimicrobial resistance (AMR) profiles, and genomic characteristics of Salmonella isolates in Hengyang, China, from 2020 to 2023, with a focus on Salmonella Typhimurium. METHODS:Salmonella isolates were identified using standard microbiological methods. Salmonella Typhimurium strains underwent antimicrobial susceptibility testing and whole-genome sequencing. Genomic analyses were performed to identify AMR genes, virulence factors, mobile genetic elements, and phylogenetic relationships. RESULTS:Among the 255 Salmonella isolates from food and patient sources, Salmonella Typhimurium was the predominant serotype (82 isolates, 32.16%), primarily represented by sequence types ST34 and ST19. All isolates were susceptible to imipenem, while tetracycline resistance was the most common (80.5%, 66/82). Forty-one resistance genes, spanning eight antimicrobial classes, were identified. ST34 strains carried more resistance genes (38) than ST19 (15). Virulence gene profiles were largely similar between the two lineages, but gogB and shdA were specific to ST34. Among mobile genetic elements, the ColRNAI plasmid was most prevalent, and insertion sequences were ubiquitous. Phylogenetic analysis revealed that ST34 and ST19 strains from Hengyang were interspersed with strains from southern and eastern China. CONCLUSION:Salmonella Typhimurium ST34 is the dominant multidrug-resistant lineage in Hengyang, characterized by a larger resistome and unique virulence factors. Its close phylogenetic relationship with strains from southern and eastern China, combined with active mobile genetic elements, underscores its role in regional dissemination and adaptive evolution.

Chlamydia psittaci, a zoonotic pathogen, promotes its intracellular survival by dysregulating host cell death pathways. This study demonstrates that resveratrol (Res), a natural polyphenol, counteracts this pathogenic strategy in infected human bronchial epithelial (HBE) cells by inducing autophagy-dependent apoptosis. Res exhibited excellent biocompatibility, maintaining cell viability above 85% at concentrations ≤100 μmol/L after 24 h treatment. Within this non-cytotoxic range, Res significantly inhibited C. psittaci growth in dose- and time-dependent manners, with maximal effect at 100 μmol/L after 24 h. Mechanistically, Res enhanced autophagic flux in infected cells, evidenced by increased LC3 puncta formation, upregulation of Beclin-1 and LC3-II, and downregulation of p62. Concurrently, Res induced apoptosis, characterized by elevated Bax/Bcl-2 ratio and enhanced Cleaved Caspase-3 expression. Pharmacological (3-Methyladenine, 3-MA) or genetic (Beclin-1/LC3B silencing) inhibition of autophagy significantly attenuated Res-induced apoptosis, confirming an autophagy-dependent mechanism. Res also suppressed PI3K/AKT/mTOR phosphorylation in infected cells, and pathway reactivation with 740Y-P reversed its pro-autophagic and pro-apoptotic effects. Collectively, these findings demonstrate that resveratrol induced autophagy-dependent apoptosis through suppression of the PI3K/AKT/mTOR pathway in C. psittaci-infected cells, highlighting its therapeutic potential against intracellular pathogens.

Salmonella lipopolysaccharide (LPS) impairs intestinal barrier function by inducing oxidative stress and inflammation, yet effective protective strategies remain limited. Dihydromyricetin (DHM), a flavonoid derived from vine tea (Ampelopsis grossedentata), possesses anti-inflammatory, antioxidant, and microbiota-modulating properties. This study investigated whether DHM from Zhangjiajie vine tea protects against Salmonella LPSinduced intestinal barrier injury using LPS-challenged Caco-2 cells and a polarized intestinal barrier model. DHM treatment (15-60 & micro;g/mL) dose-dependently suppressed LPS-induced reactive oxygen species (ROS) production, restored catalase (CAT) and superoxide dismutase (SOD) activities, and reduced malondialdehyde (MDA) levels. It also significantly decreased the secretion of the pro-inflammatory cytokines IL-1(3, IL-6, and TNF alpha. Functionally, DHM reversed LPS-induced declines in transepithelial electrical resistance (TEER) and the apical/basolateral alkaline phosphatase (ALP) ratio. Additionally, DHM upregulated the transcriptional expression of the TJP-1 and occludin, with consistent changes in their soluble protein levels detected in culture supernatants. In conclusion, these findings highlight DHM from Zhangjiajie vine tea as a natural candidate for preventing intestinal barrier injury through integrated antioxidant and anti-inflammatory.

ABSTRACT Chlamydia trachomatis (Ct), an obligate intracellular pathogen, manipulates host cell death pathways to establish infection. Although ferroptosis—an iron-dependent cell death process marked by lipid peroxidation—constitutes an antimicrobial defense mechanism, its regulation during Ct infection remains in the early stages of exploration. Here, we report that Ct actively suppresses ferroptosis in host cells, with maximal inhibition at 24 hours post-infection. This suppression was demonstrated through attenuated malondialdehyde production, reduced Fe²+ accumulation, and preserved mitochondrial integrity. Transcriptomic analysis of Ct-infected cells identified PARP10 as a prominently upregulated host factor. Crucially, we discovered that Ct-induced PARP10 inhibits NF-κB activation, leading to downregulation of ferroptosis-promoting genes. Disruption of the PARP10/NF-κB axis restored ferroptosis and impaired Ct replication. Our findings unveil a non-canonical strategy wherein Ct exploits PARP10 to repress NF-κB-dependent ferroptotic defense, thereby maintaining iron/lipid peroxide homeostasis for intracellular survival. Targeting this pathway may offer novel anti-chlamydial therapeutics.IMPORTANCEChlamydia trachomatis is a widespread bacterial infection and a leading cause of preventable blindness and sexually transmitted diseases. A key to its success is its ability to survive inside our cells by disarming the body's innate defense systems. We discovered that the bacteria actively block a potent form of cell death called ferroptosis by exploiting a human protein, PARP10. This previously unknown strategy allows Chlamydia to create a safe haven for its replication. Uncovering this novel bacterial survival mechanism not only deepens our understanding of the infection process but also reveals the PARP10 pathway as a promising new target for developing much-needed therapeutic drugs against this pervasive pathogen.

This study aims to isolate and characterize a new phage infecting multidrug-resistant Acinetobacter baumannii (MDRAB) and to investigate its synergistic effect with levofloxacin against MDRAB both in vitro and in vivo. The phage was isolated from hospital sewage using the phage enrichment method. Its morphological, genomic, and biological characteristics were determined through the double agar overlay method, transmission electron microscopy, and whole-genome sequencing. The synergistic activity of the phage in combination with levofloxacin against MDRAB isolates was assessed using the checkerboard assay, growth inhibition assays, and the Galleria mellonella infection model. Phage vB_AbaA_LLY belongs to the genus Friunavirus within the family Autographiviridae. It demonstrates efficient lytic activity against clinical isolates of A. baumannii with MLST (multilocus sequence typing) profiles of ST208 (8/11, 72.7

We systematically evaluated the DNA adsorption and desorption efficiencies of several nanoparticles. Among them, titanium dioxide (TiO₂) nanoparticles (NPs), aluminum oxide (Al₂O₃) NPs, and zinc oxide (ZnO) NPs exhibited strong DNA-binding capacities under mild conditions. However, phosphate-mediated DNA displacement efficiencies varied considerably, with only TiO₂ NPs showing consistently superior performance. Further investigation into the DNA adsorption and desorption mechanisms of TiO₂ NPs led to the following key results: (1) TiO₂ NPs achieved over 98

Chlamydia species are responsible for significant diseases in both humans and animals, with their infection processes involving complex interactions with host cells. Protein post-translational modifications (PTMs) have emerged as a critical focus in understanding the complex interplay between Chlamydia and its host. PTMs, including phosphorylation, glycosylation, ubiquitination, acetylation, and methylation, play pivotal roles in regulating key processes during Chlamydia infection, such as bacterial invasion, intracellular survival, immune evasion, and manipulation of host signaling pathways. By modulating both bacterial and host proteins, PTMs serve as essential mechanisms that shape the progression and outcome of Chlamydia infections. This growing area of research not only deepens the understanding of Chlamydia's pathogenic strategies but also opens new avenues for developing targeted therapeutic interventions against these infections.

Pseudomonas aeruginosa poses a significant clinical challenge due to its intrinsic and acquired antimicrobial resistance and robust biofilm formation, which complicates treatment. Bacteriophages (phages), viruses targeting bacteria, are emerging as a promising alternative or adjunct to combat multidrug-resistant P. aeruginosa infections. This review systematically examines the taxonomic diversity of phages infecting P. aeruginosa, with emphasis on those that remain unclassified at the family taxonomic level, such as Pbunavirus and Pakpunavirus. It comprehensively synthesizes current knowledge on phage receptor-binding proteins (RBPs) – the molecular determinants of host specificity – and their corresponding receptors on the P. aeruginosa surface, such as lipopolysaccharide (LPS), pili, flagella, outer membrane proteins, and alginate. Critically, the review underscores the urgent need to decipher the precise molecular mechanisms governing RBP-receptor interactions. A deeper understanding of these specific recognition events is paramount. This knowledge is essential not only for rationally optimizing phage therapy efficacy, including through engineered phages or RBP-based antimicrobials, but also for developing highly sensitive and specific phage-derived diagnostic tools, utilizing whole phages or purified RBPs as recognition elements for rapid P. aeruginosa detection.

Genital tract Chlamydia trachomatis (Ct) infection is one of the most prevalent sexually transmitted infections (STIs) worldwide. However, its clinical progression is often insidious and prolonged. Understanding the mechanisms by which Ct influences cell death pathways is crucial for elucidating the pathogenic processes of this intracellular bacterium. Ferroptosis, a newly identified form of programmed cell death, is characterized by the iron-dependent accumulation of lipid peroxides. Despite its relevance, the interaction between Ct and ferroptosis remains poorly studied. In the present study, we first performed bioinformatics analysis based on RNA sequencing data under an in vitro model of Ct acute infection. Bioinformatics analysis revealed significant enrichment of differentially expressed genes in ferroptosis and p53 signaling pathways. Subsequently, we validated the hypothesis that Ct inhibits host ferroptosis by expression assays of ferroptosis-related proteins. Further cell proliferation, intracellular ferrous iron fluorescence, and lipid peroxidation assays multifaceted observations of the phenotype. Mechanistically, we found that Ct inhibition of ferroptosis acts by regulating the host p53/SLC7A11 pathway. Finally, indirect immunofluorescence assays demonstrated that ferroptosis decreases inclusion forming units (IFUs) of Ct progeny and thus affects its reproduction, which partly explains Ct's survival strategy of resisting host ferroptosis.

PB1-like phages belong to Pbunavirus and are widespread in various environments. This group of phages is a promising candidate for treating human or animal infectious diseases caused by antibiotic-resistant P. aeruginosa. The lipopolysaccharide (LPS) has been identified as the receptor of different PB1-like phages, while little is known about the receptor-binding proteins (RBPs) of these phages. We constructed the tail fiber protein (gp50) of a PB1-like phage, PHW2, and its C- or N-terminus truncation variants to identify its role during the phage infection. The anti-gp50(453-964) antibody showed a similar effect to the antibody against gp50 in blocking the phage infection. The protein competition and cell binding assays showed that the gp50(1-451) doesn't exhibit an effect on the adsorption of the host cells. These results indicated that the C-terminus of gp50 is the essential region that mediates phage PHW2 adsorption and infection.

Epigenetic reprogramming underpins trained immunity (TRIM). However, the importance of mRNA reprogramming in TRIM remains unknown. Here, we discovered, for the first time, that the steroid hormone ouabain creates a significant training effect on peripheral innate immune cells (IICs), leading to functional enhancement of IICs against bacterial infections. However, unlike conventional training mechanisms, ouabain primarily relies on an integrated posttranscriptional RNA regulon complex (IPRRC) to establish immune memory and reprogram cytokine expression, with lncRNA-CYTOR playing a critical role in this process. Moreover, to enhance training effects while reducing lactate production, ouabain promotes a rapid degradation of the Na+,K+-ATPase receptor. Pathologically, endogenous ouabain is downregulated in sepsis-induced immunoparalysis in vivo, correlating with impaired innate immunity. Exogenous ouabain rescue significantly reverses this impairment, and its effect is superior to β-glucan, even when used at one percent of β-glucan dosage. Notably, posttranscriptional RNA regulons are also critically involved in β-glucan’s training effects. Overall, mRNA reprogramming emerges as a new mechanism for TRIM; steroid hormone ouabain is a novel innate immunity regulator.

Bacterial contamination poses significant threats to public health through food safety issues, creating a critical need for rapid and sensitive bacterial detection platforms. Herein, we developed a novel label-free fluorescent detection system leveraging target-triggered hybridization chain reaction (HCR) amplification, using Escherichia coli (E. coli) as a proof of concept. We engineered a hairpin-structured capture probe integrating an E. coli-specific aptamer with an HCR trigger sequence, achieving fluorescence amplification through three synergistic mechanisms: (1) HCR-driven DNA duplex assembly; (2) enhanced SYBR Green I (SG-I, a cost-effective non-labeled dye) intercalation into HCR-generated DNA duplexes; and (3) target-selective fluorescence modulation via MnO2 nanosheets that quench background fluorescence through preferential adsorption of single-stranded DNA (ssDNA)-bound SG-I over duplex DNA-intercalated dye, exploiting the differential binding affinity of MnO2 for ssDNA versus double-stranded DNA. This strategy enabled a fluorescence sensor with high sensitivity (detection limit: 17 CFU/mL), excellent specificity, and broad dynamic range (5.0 × 101 5.0 × 107 CFU/mL), demonstrating robust performance in complex food matrices through successful E. coli detection in spiked milk and lettuce samples with recoveries of 98.81 to 104.26

Chlamydia trachomatis Pgp3 protein-induced immunoprotection is effective but incomplete, which requires the suitable adjuvants to enhance its immune response. Within this context, Hepatitis B core virus-like particles (HBc-VLP) emerge as nanoscale protein particles capable of incorporating either endogenous or exogenous antigens or epitopes. In this study, HBc-Pgp3 chimeric protein was accomplished by integrating the identified dominant epitope of the Pgp3 protein into the major immunodominant region of a truncated HBc-VLP, which was realized in the pET28a (+) vector and expressed via the E. coli BL21 expression system. The efficacious expression and purification of the recombinant HBc-Pgp3 facilitated a tripartite immunization regimen in mice. The immunological assessment encompassed the measurement of IgG antibody and cytokine levels through ELISA, alongside flow cytometric analysis of the CD4+ Th1 cell-mediated immune responses within the murine spleen. Comparative analysis revealed that the HBc-Pgp3-vaccinated mice demonstrated superior IgG antibody titers and subtypes relative to the controls. Moreover, the HBc-Pgp3 formulation was instrumental in augmenting IFN-γ production, enhancing the efficiency of Chlamydia muridarum clearance post-challenge, and severity of hydrosalpinx within the lower genital tract. Collectively, these findings illuminate the potential of the novel HBc-Pgp3 chimeric construct as an innovative vaccine candidate, offering augmented immunoprotection against chlamydial infection.

Eravacycline (ERV) has emerged as a therapeutic option for the treatment of carbapenem-resistant pathogens. However, the advent of heteroresistance (HR) to ERV poses a challenge to these therapeutic strategies. This study aimed to investigate ERV HR prevalence among common clinical isolates and further characterize ERV HR in carbapenem-resistant Klebsiella pneumoniae (CRKP). A total of 280 clinical pathogens from two centers were selected for HR and analyzed using population analysis profiling (PAP) and modified E-tests. The PAP assay revealed an overall ERV HR prevalence of 0.7% (2/280), with intermediate heterogeneity observed in 24.3% (68/280) of strains. The proportion of heteroresistant strains was 18.3% according to modified E-test results. A time-killing assay demonstrated that CRKP CFU increased significantly after 10 h of ERV treatment, contributing to the reduced bactericidal effect of ERV in vitro. Interestingly, dual treatment with ERV and polymyxin B effectively inhibited the total CFU, simultaneously reducing the required polymyxin B concentration. Furthermore, fitness cost measurements revealed a growth trade-off in CRKP upon acquiring drug resistance, highlighting fitness costs as crucial factors in the emergence of ERV HR in CRKP. Overall, the findings of the current study suggest that ERV HR in clinical strains presents a potential obstacle in its clinical application.

Chlamydia psittaci is a zoonotic pathogen known to cause respiratory diseases in humans. Chlamydia infections are closely associated with apoptosis, in which microRNAs (miRNAs) play regulatory roles. Herein, we demonstrated that C. psittaci infection induces apoptosis in human bronchial epithelial (HBE) cells and investigated regulatory mechanism involving miR-124-3p and the PI3K/AKT signaling pathway. Following C. psittaci infection in HBE cells, we observed an elevated HBE cell apoptosis, accompanied by upregulation of miR-124-3p levels. Mechanistically, we identified EIF3B as a novel target gene of miR-124-3p, supported by the inverse correlation of their mRNA expressions. MiR-124-3p inhibitor reduced apoptosis induced by C. psittaci, increased the replication of C. psittaci, and inhibited PI3K/AKT activation, whereas miR-124-3p mimic produced opposite effects, and transfection with EIF3B siRNA reversed the effects of miR-124-3p inhibitor. Our findings suggest that miR-124-3p targeting EIF3B promotes apoptosis in C. psittaci-infected HBE cells through activation of the PI3K/AKT signaling pathway. C. psittaci infection increased HBE cells apoptosis, accompanied by upregulation of miR-124-3p levels and downregulation of EIF3B levels. MiR-124-3p targeting EIF3B promotes apoptosis in C. psittaci-infected HBE cells through the activation of the PI3K/AKT signaling pathway.

As an obligate intracellular pathogen, Chlamydia trachomatis assumes various strategies to inhibit host cells apoptosis, thereby providing a suitable intracellular environment to ensure completion of the development cycle. In the current study, we revealed that Pgp3 protein, one of eight plasmid proteins of C. trachomatis that has been illustrated as the key virulence factor, increased HO-1 expression to suppress apoptosis, and downregulation of HO-1 with siRNA-HO-1 failed to exert anti-apoptosis activity of Pgp3 protein. Moreover, treatment of PI3K/Akt pathway inhibitor and Nrf2 inhibitor evidently reduced HO-1 expression and Nrf2 nuclear translocation was blocked by PI3K/Akt pathway inhibitor. These findings highlight that induction of HO-1 expression by Pgp3 protein is probably due to regulation of Nrf2 nuclear translocation activated by PI3K/Akt pathway, which provide clues on how C. trachomatis adjusts apoptosis.

Chlamydia psittaci is a human pathogen that causes atypical pneumonia after zoonotic transmission. We confirmed that C. psittaci infection induces oxidative stress in human bronchial epithelial (HBEs) cells and explored how this is regulated through miR-184 and the Wnt/β-catenin signaling pathway. miR-184 mimic, miR-184 inhibitor, FOXO1 siRNA, or negative control sequence was transfected into HBE cells cultured in serum-free medium using Lipofectamine 2000. Then, prior to the cells were infected with C. psittaci 6BC, and the cells were treated with or without 30 µM Wnt/β-catenin inhibitor ICG-001. Quantification of reactive oxygen species, malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione was carried out according to the manufacturer's protocol using a corresponding assay kit. The outcome of both protein and gene was measured by western blotting or real-time fluorescence quantitative PCR. In C. psittaci-infected HBE cells, miR-184 was upregulated, while one of its target genes, FOXO1, was downregulated. ROS and MDA levels increased, while SOD and GSH contents decreased after C. psittaci infection. When miR-184 expression was downregulated, the level of oxidative stress caused by C. psittaci infection was reduced, and the Wnt/β-catenin signaling pathway was inhibited. The opposite results were seen when miR-184 mimic was used. Transfecting with FOXO1 siRNA reversed the effect of miR-184 inhibitor. Moreover, when the Wnt/β-catenin-specific inhibitor ICG-001 was used, the level of oxidative stress induced by C. psittaci infection was significantly suppressed. miR-184 can target FOXO1 to promote oxidative stress in HBE cells following C. psittaci infection by activation of the Wnt/β-catenin signaling pathway.

Pyroptosis is a gasdermins-mediated programmed cell death that plays an essential role in immune regulation, and its role in autoimmune disease and cancer has been studied extensively. Increasing evidence shows that various microbial infections can lead to pyroptosis, associated with the occurrence and development of microbial infectious diseases. This study reviews the recent advances in pyroptosis in microbial infection, including bacterial, viral, and fungal infections. We also explore potential therapeutic strategies for treating microbial infection-related diseases by targeting pyroptosis.

Folic acid (FA) is one of the essential vitamins for the growth and reproduction of human cells, and it is of great significance to detect FA in real time.