2026-04-02
Xinmin Qiu, Baobing Chen, Jianping Chen, Xinzheng Li, Jiyun Tian
BackgroundThe management of Mycoplasma genitalium (MG) infection is challenged by rising macrolide resistance, leading to high failure rates with azithromycin. Evidence on the long-term effectiveness of alternative initial regimens, particularly sequential therapy, and easily obtainable predictors for poor outcomes remains scarce.MethodsWe conducted a retrospective cohort study at a tertiary hospital in China (2018-2024). Sexually active adults with nucleic acid amplification test (NAAT)-confirmed MG infection and available treatment records were included. The primary outcomes were treatment failure (persistent infection at 8 weeks, ultimate failure) and recurrence. Multivariable logistic regression and Kaplan-Meier survival analyses were employed to assess the impact of initial antibiotic regimens (azithromycin, quinolones, doxycycline-quinolone sequential therapy), demographics, and co-infections.ResultsAmong 1, 192 MG-positive patients, 474 completed follow-up. After adjustment, doxycycline-quinolone sequential therapy was associated with significantly lower odds of ultimate treatment failure (adjusted odds ratio [aOR]=0.36, 95%CI:0.21-0.61) and recurrence (aOR=0.37, 95%CI:0.18-0.75) compared to azithromycin. Survival analysis confirmed a faster median time to clearance with sequential therapy (7 vs. 10 weeks, p=0.001) and a marked “long-tail” effect in the azithromycin group (mean clearance time: 94.2 vs. 28.0 weeks). Co-infection with Chlamydia trachomatis (CT) was the strongest independent predictor for all adverse outcomes (aOR for ultimate failure=3.21, 95%CI:1.88-5.48), followed by male sex.ConclusionsIn this real-world cohort, doxycycline-quinolone sequential therapy demonstrated superior long-term effectiveness over azithromycin for MG infection. CT co-infection and male sex were key risk predictors. These findings advocate for a paradigm shift towards risk-stratified initial therapy, prioritizing sequential regimens for high-risk patients to improve cure rates while supporting antimicrobial stewardship.
DOI: 10.3389/fcimb.2026.17875202026-04-02
Baili Zheng, Xiaoyue Su, Yongchao Li, Qiang Fu, Xuelian Ma, Bao Zhou, Bing Peng, Rulong Chen, Yingyu Liu
BackgroundShiga toxin-producing Escherichia coli (STEC) is a leading foodborne pathogen responsible for hemolytic uremic syndrome (HUS). This pathogen poses a severe threat to global public health. MicroRNAs (miRNAs) are increasingly recognized as essential post-transcriptional regulators and therapeutic targets. Despite this, their exact regulatory networks and roles in STEC pathogenesis remain largely unknown.MethodsAn in vitro infection model was established using human intestinal epithelial cells (HIECs), with optimal infection time and bacterial load determined via CCK-8 assays and DAPI staining. High-throughput RNA sequencing (RNA-seq) was performed to profile miRNA and mRNA expression, followed by RT-qPCR validation. Differentially expressed miRNAs and their target mRNAs were identified by integrating miRanda predictions with transcriptomic data. Target functions were annotated using GO and KEGG enrichment analyses. A protein–protein interaction (PPI) network was constructed to identify core hub genes, and upstream transcription factors (TFs) were predicted using the TRRUST and hTFtarget databases, culminating in the construction of an integrated miRNA–hub mRNA–TF regulatory network.ResultsInfection of HIECs with STEC (106 CFU/mL) for 1 hour induced profound cellular structural damage, accompanied by the differential expression of 652 target mRNAs (301 upregulated and 351 downregulated). Functional enrichment revealed that these targets are predominantly involved in inflammatory responses, apoptosis, and cell proliferation. Through the PPI network, 10 core hub genes (including TNF, CXCL8, CCN2, and TGFB2) were identified, along with 11 highly correlated regulatory TFs. Based on the integrated network analysis, has-miR-3121-3p, hsa-miR-219b-5p, and hsa-miR-543 were pinpointed as master regulatory miRNAs, suggesting they orchestrate critical host signaling pathways during infection.ConclusionSTEC infection drastically reprograms the transcriptomic landscape of HIECs, triggering the dysregulation of inflammation and apoptosis-related pathways. This study is the first to delineate a comprehensive miRNA–mRNA–TF regulatory network for STEC infection, highlighting miR-3121-3p, miR-219b-5p, and miR-543 as key molecular mediators. These findings provide novel insights into the molecular pathogenesis of STEC and lay a crucial foundation for exploring potential regulatory and host-directed therapeutic targets.
DOI: 10.3389/fcimb.2026.17726072026-04-01
Hao Zhang, Yafei Li, Hang Li, Shaomeng Liu, Dang Wang, Huanchun Chen, Qingyun Liu, Xiangru Wang
The global emergence of multiple viral zoonoses underscores the substantial threats of viral infections to human health. Given the dynamic and complex mechanisms underlying viral pathogenesis, sophisticated approaches are requisite to advance viral research. Here, we present a systematic review of single-cell RNA sequencing (scRNA-seq), a high-throughput technology enabling transcriptomic profiling at the individual cell level, focusing on its pivotal role in elucidating heterogeneous host cellular responses to viral infection and deciphering underlying pathogenic mechanisms. We summarize scRNA-seq’s developmental milestones, compare characteristics of various platforms, and outline its key applications in viral infection research: identifying infection-induced novel cell types/subpopulations, characterizing virus-specific host cell gene expression changes, defining viral target cells, elucidating antiviral immune mechanisms, and clarifying in vivo viral distribution and pathogenesis. By synthesizing these information, this review offers novel research and technical perspectives for dissecting the dynamic and complex virus-host interactions, aiding future advancements in viral infection research.
DOI: 10.3389/fcimb.2026.17983032026-04-01
Lu Wang, Fuhua Wang, Zhiyong Yuan, Ying Liu, Yajun Jing, Jinyan Xing
IntroductionAntimicrobial resistance poses a major challenge in the treatment of A. baumannii worldwide, especially Carbapenem-Resistant A. baumannii (CRAB) bloodstream infections.ObjectivesThe objective of this study was to isolate and characterize a CRAB-targeting bacteriophage and to evaluate its therapeutic potential, alone and in combination with polymyxin B.MethodsFrom January 2020 to September 2025, adult patients with A. baumannii bloodstream infection were enrolled. Clinically relevant data were collected. A. baumannii strains were isolated from clinical samples and the phage was isolated from wastewater samples collected from hospital by double-layer agar plate method. The synergistic activity of phage–polymyxin B combination therapy was assessed by checkerboard analysis and time-kill assays. BALB/c mice were infected with a CRAB suspension via tail vein to establish the model and were subsequently treated with the phage and phage-antibiotic combination.ResultsA total of 50 patients suffered from bloodstream infections caused by Acinetobacter baumannii. Among them, 34 (68%) cases were classified as CRAB. Compared with CSAB, they underwent a longer duration of mechanical ventilation(13.00(6.00,28.00) vs.3.00(2.00,4.00),P =0.019), used more triple therapy(9.41% vs.0%,P=0.041), and had a higher in-hospital mortality(82.35% vs.18.75%,P <0.001). Synergistic antibacterial activity between the phage and colistin B was demonstrated using the checkerboard assay and time-kill curve analysis. In a murine bacteremia model, the vB_AbaP_CV1-antibiotic combination significantly reduced tissue bacterial loads, attenuated inflammatory responses, and ameliorated clinical manifestations. Notably, the combined therapy exhibited superior therapeutic efficacy compared to either monotherapy alone.ConclusionCRAB bloodstream infections are associated with high mortality and poor outcomes. vB_AbaP_CV1 can lyse the CRAB strains. Both phage monotherapy and the phage-colistin B combination exhibited therapeutic efficacy, with the combined regimen yielding the optimal outcome.
DOI: 10.3389/fcimb.2026.17749932026-03-31
Enas Sheik-Khalil, Barbro Kahl-Knutson, Emil Johansson, Sara Karlson, Ulf J. Nilsson, Hakon Leffler, Marianne Jansson
Target cell entry of HIV-1 is dependent on the binding of gp120, the outer component of the viral envelope glycoprotein complex (Env), to CD4 and a coreceptor, preferentially CCR5 or CXCR4. Still, other interactions may also contribute to the infectivity of the virus. One such interaction is between the highly glycosylated gp120 and carbohydrate-binding proteins, such as galectins. Here, we studied the interaction between HIV-1 Env and a panel of galectins and found that galectin-8 (Gal-8), bound with highest affinity (KD < 1µM) and also interacted with soluble CD4. Detailed analysis using probes for different parts of Gal-8 revealed that it was primarily the N-terminal carbohydrate recognition domain that interacted with HIV-1 Env expressing sialylated galactosides and both N- and O-linked glycans. Importantly, in cell cultures Gal-8 enhanced the infectivity of HIV-1, including strains with different coreceptor use and subtype origin, as well as HIV-2. This Gal-8 infectivity enhancement was particularly strong (up to 100-fold) at low virus inoculum doses. Next, we compared Gal-8 infectivity enhancement of primary HIV-1 isolates from people living with HIV at different stages of the infection. Of note, the infectivity of HIV-1 isolates obtained during the chronic, relatively immunocompetent phase, was significantly more enhanced by Gal-8 than isolates obtained at late-stage disease during severe immunodeficiency. Taken together, this study reveals novel carbohydrate dependent interactions between Gal-8 and HIV-1 Env, resulting in enhanced infectivity of HIV-1, with particularly strong effects at low dose exposure of strains circulating during the chronic infection phase. These results suggest that Gal-8 is a cell attachment protein that HIV-1 utilizes for optimized infectivity, which may guide the development of novel intervention strategies targeting this interaction.
DOI: 10.3389/fcimb.2026.18010722026-03-31
Li Ma, Xiaoyu Du, Chenyu Pang, Xuan Han, Jianquan Zhang, Xiaowei Guo, Ke Pu
BackgroundFusobacterium nucleatum is a Gram-negative obligate anaerobic bacterium with trans-organ pathogenicity. It serves as a crucial pathogen causing intracranial anaerobic infections and is closely associated with the occurrence of brain abscess. However, the mechanism by which Fusobacterium nucleatum crosses the blood-brain barrier and induces intracranial infection remains unclear.MethodsIn this study, Fusobacterium nucleatum clinical strain isolated from the brain abscess was identified and characterized. Its growth characteristics and biofilm-forming capacity were compared with those of the ATCC 25586 standard strain. Furthermore, the adhesive and invasive capabilities of both strains towards oral epithelial cells and brain microvascular endothelial cells were assessed. An in vitro BBB model was constructed using a brain microvascular endothelial monolayer to examine the effects of bacterial infection on the expression of tight junction proteins (occludin, Claudin-5, ZO-1). Finally, antimicrobial susceptibility testing combined with proteomic techniques was employed to analyze the antibiotic resistance profiles and differentially expressed proteins of the strains.ResultsOne clinical strain was successfully isolated and identified from specimens of 7 brain abscess patients. Compared to the standard strain, the clinical isolate demonstrated a slower growth rate, reduced biofilm formation, and diminished adhesion and invasion capabilities against both oral epithelial cells and brain microvascular endothelial cells. The two strains exhibited significantly distinct regulatory patterns on the tight junction protein expression in brain microvascular endothelial cells. Proteomic analysis revealed extensive protein reprogramming in the clinical strain, characterized by the upregulation of proteins involved in metabolic pathways and immune evasion. Altered antimicrobial susceptibility in the clinical strain correlated with differential expression of proteins such as ribosomal components and efflux pump proteins.ConclusionFusobacterium nucleatum can specifically adhere to and invade brain microvascular endothelial cells, disrupting their tight junctions. Through proteomic reprogramming, Fusobacterium nucleatum enhances its metabolic adaptation and immune evasion capabilities to adapt to changes in the intracranial microenvironment and establish persistent infection, thereby achieving a strategic shift from barrier penetration to intracranial colonization.
DOI: 10.3389/fcimb.2026.17193852026-03-30
Ganggang Sheng, Chaopeng Li, Da Liu, Weishan Wang, Nannan Pang, Zhendong Zhang
The PI3K/Akt-mTOR signaling pathway, as a highly conserved and crucial intracellular signal transduction network, is deeply involved in core biological processes such as cell metabolism, proliferation, survival, and immune responses, playing a pivotal role in the occurrence and development of infectious diseases. This review comprehensively and systematically elaborates on the molecular composition, activation mechanisms, and negative regulatory mechanisms of the pathway, with a particular focus on analyzing its key regulatory role in the anti-infective responses of host immune cells (macrophages, T cells, NK cells, dendritic cells, B cells, etc.), as well as the mechanisms by which pathogens (bacteria, viruses, parasites, fungi, etc.) hijack and interfere with this pathway. Research has shown that the dynamic balance of the PI3K/Akt-mTOR pathway is one of the key factors determining the outcome of infection: the host enhances immune defense by activating this pathway, while pathogens achieve immune evasion by targeting key molecules in the pathway. Furthermore, this review systematically integrates the dual role of the PI3K/Akt-mTOR pathway in infection immunity, aiming to elucidate its central position as a core for host defense and pathogen evasion, and to provide a clear theoretical framework for subsequent targeted therapeutic research.
DOI: 10.3389/fcimb.2026.17827122026-03-30
Fei Li, Xiangpeng Chen
Ferroptosis, characterized by lipid peroxidation and iron-dependent oxidative damage, is a crucial factor in various diseases. Although researchers have extensively characterized ferroptosis in cancer and neurodegenerative disorders, its interaction with pathogenic infections remains underexplored. Recent research indicates that ferroptosis contributes to host cell damage during pathogen invasions, impacting disease outcomes. This review summarizes the characteristics, mechanisms, and regulatory networks of ferroptosis. It delineates the key regulatory steps of ferroptosis during infections caused by various pathogens, including viruses, bacteria, fungi, and parasites. Additionally, it examines changes in host markers and related signaling pathways. Furthermore, this review explores the potential similarities and differences among these pathogens and discusses therapeutic strategies for addressing pathogen-related diseases through ferroptosis-dependent mechanisms.
DOI: 10.3389/fcimb.2026.17787212026-03-30
Shiqing Shi, Shaoying Wang, Shiying Li, Ruifang Lu, Shaoxia Pan, Feng Chen, Xuesong He
IntroductionType 2 diabetes mellitus (T2DM) is a major systemic risk factor that exacerbates periodontitis, with microbial dysbiosis recognized as an important mechanism. However, whether a well-controlled diabetic state still exerts a distinct influence on the subgingival microbiome remains to be fully elucidated.MethodsThis study compared the subgingival microbiota composition in patients with generalized Stage III/IV periodontitis, categorized into a systemically healthy Control group (n = 30) and a well-controlled T2DM group (HbA1c 0.05). However, the T2DM group exhibited a distinct diabetic-associated microbial signature. The T2DM group showed a significant enrichment of the phylum Saccharibacteria (formerly TM7), particularly Nanosynbacter lyticus. In contrast, the phylum Actinomycetota, predominantly represented by the genus Actinomyces, was significantly reduced in the T2DM group. Notably, classical “Red Complex” pathogens were not identified as discriminative biomarkers between the groups. Additionally, correlation analysis revealed that Saccharibacteria abundance was positively associated with HbA1c and fasting blood glucose levels.DiscussionThese findings demonstrate that even with adequate glycemic control, the diabetic microenvironment exerts a unique selective pressure on the subgingival microbiome, favoring the expansion of specific epibiotic bacteria like Saccharibacteria while reducing commensal Actinomyces.
DOI: 10.3389/fcimb.2026.18149832026-03-27
Zongmao Dai, Yue Hu, Anran Tai, Yabin Lu, Shixiong Hu, Juan Pan, Ying Xiao, Xuelian Ma, Qiang Fu, Hongqiong Zhao, Zhanqiang Su, Panpan Tong, Zhihui Hao, Gang Yao, Jinquan Wang
IntroductionThe global rise of antimicrobial resistance has positioned multidrug-resistant Klebsiella pneumoniae as a critical health threat, necessitating alternative therapeutic strategies such as phage therapy. However, the long-term evolutionary consequences of phage-bacteria interactions remain poorly understood. This study characterizes a unique attenuated mutant, wGF 1-2, derived from a hypervirulent K. pneumoniae strain (GF) during phage isolation efforts.MethodsThe wGF 1-2 mutant was serendipitously isolated during attempts to obtain lytic phages against the parental GF strain. We performed an integrated multi-omics and phenotypic characterization, including genomic sequencing, proteomic profiling, and transcriptomic analysis. Host-pathogen interactions were assessed using a murine infection model (evaluating survival and tissue colonization), and the impact on the gut microbiota was analyzed via metagenomics.ResultsCompared to the parental strain, wGF 1-2 exhibited a significant reduction in biofilm formation and distinct morphological alterations. In a murine model, the mutant was avirulent, resulting in 100% survival even at a high challenge dose (10⁶ CFU), with minimal tissue colonization. Multi-omics analysis revealed extensive genomic structural variations (81 insertions and 64 deletions). Proteomic shifts included the downregulation of proteins involved in metal ion binding and metabolic pathways. Furthermore, infection with wGF 1-2 led to host inflammatory suppression and a restructuring of the gut microbiota characterized by an increase in beneficial Bacteroidota.DiscussionThis study provides a comprehensive characterization of an attenuated K. pneumoniae mutant, wGF 1-2. The extensive genomic and phenotypic alterations observed highlight the significant evolutionary potential of bacterial pathogens during phage interactions. These findings underscore the necessity of thorough safety assessments, including evolutionary risk evaluations, for the future development of phage-based therapies.
DOI: 10.3389/fcimb.2026.1761564