Mycobacterium avium is a slow-growing non-tuberculous mycobacterium. While its medical importance is increasing, its virulence is only poorly characterized. A highly virulent M. avium strain ATTC25291 (MAA25291) has been shown to cause severe disease in mice by survival and growth in nitric oxide (NO) producing, immune suppressive monocytic-MDSC (M-MDSC). The induction and persistence of MAA25291 in M-MDSC is still unresolved. In the present study, we were interested in the role of M-MDSC in mice infected with MAA25291 at infection doses that led to the manifestation of clinical disease (high dose) or subclinical disease (low dose). Flow cytometry revealed the presence of M-MDSC in both infection groups, however, this infiltration was significantly lower after low dose infection. Histopathology showed lower infiltration of NOS2 expressing cells in spleen and liver correlated with high CD3+ T cell numbers after low dose infection, whereas high dose infection of mice led to T cell losses in the tissues. This study highlights that the infection dose significantly affects M-MDSC induction and their immune regulatory roles. Furthermore, it suggests that the induction and persistence of MAA25291 in M-MDSC relies on the amount of NO production.
Pathogenic Leptospira spp. evade the complement system by capturing soluble regulators of the alternative, classical, and lectin pathways - such as factor H, C4BP, and vitronectin - via proteins on their surface. By capturing these regulators, Leptospira can disrupt the complement activation cascade, thereby preventing opsonization by C3b/iC3b and lysis by the membrane attack complex (MAC). The ability of low-passage pathogenic Leptospira strains - LOCaS46 (L. interrogans sv Canicola), LOVe30 (L. interrogans sv Icterohaemorrhagiae), and MOCA45 (L. santarosai sv Tarassovi) - to bind C4BP was evaluated and compared to their corresponding culture-attenuated (LOCaS46, LOVe30, and MOCA45) and to the saprophytic Patoc I strain of Leptospira biflexa sv Patoc. Binding to C4BP was assessed by ELISA and confirmed by Western blot, the expression level of the genes for C4BP-binding proteins was evaluated by RT-qPCR, and the survival of the Leptospira spp. strains in normal human serum (NHS) was estimated to assess complement resistance. Results showed that culture attenuated (CA) strains had a lower capacity for binding to C4BP, and surviving to NHS as compared to low-passage (LP) strains. Also, transcription level of the genes for the C4BP-binding proteins LigA, LigB, LcpA, enolase and Lsa23, was lower in the CA strains than in their corresponding LP strains. This suggest that reduction of the ability to capture C4BP in culture attenuated (CA) strains is due at least in part to lower expression of C4BP-binding proteins, affecting the evasion of classical and lectin pathways of the complement system and therefore the capability of survival in NHS.
Background Cathepsin play a crucial role in the progression of various diseases, including cancer, neurodegenerative disorders, and processes involving inflammation and immune modulation. The global pandemic of COVID-19 has heightened the need for further exploration into the interactions between cathepsin and the virus, and their impact on disease progression. Methods This study employed Mendelian randomization to analyze the causal relationships between specific genetically predicted plasma cathepsin and COVID-19 outcomes, both severe and non-severe. Using data from genome-wide association studies, we evaluated the associations of genetically predicted plasma levels of cathepsin B, D, F, and S with susceptibility to and severity of COVID-19. Results An increase in genetically predicted circulating cathepsin S levels might be associated with a reduced susceptibility risk to COVID-19 (P < 0.05). Furthermore, while there appears to be a correlation where increased susceptibility to COVID-19 leads to elevated levels of genetically predicted circulating cathepsin F and a reduction in genetically predicted cathepsin S levels (P < 0.05), these associations should be interpreted with caution. There is also suggestive evidence of a causal association between the progression of COVID-19 severity and increased levels of genetically predicted circulating cathepsin F (P < 0.05). However, due to the inherent limitations of the Mendelian randomization approach, further studies are warranted to substantiate these initial findings. Conclusion This study highlights the potential role of cathepsin in the pathophysiology of COVID-19 and suggests that modulating the expression or activity of these enzymes could influence susceptibility and disease severity. These findings provide a new perspective on the interaction between genetically predicted plasma cathepsin and COVID-19, suggesting further research is needed to explore the mechanisms behind these findings and the potential efficacy of interventions targeting specific cathepsin in the prevention or treatment of COVID-19.
This study aims to compare the clinical, laboratory, and therapeutic outcomes between acute and subacute/chronic phases of brucellosis and to identify independent predictors of a favorable treatment response. This retrospective observational and analytic study included 171 patients with brucellosis, categorized as acute (n = 146) or subacute/chronic (n = 25). A therapeutic response was defined as the complete resolution of initial symptoms with no relapse during a 12-month follow-up. A serological response was defined as a ≥4-fold decrease in the serum tube agglutination (STA) titer post-treatment. Outcomes were compared using appropriate statistical tests (p < 0.05), and logistic regression was used to identify predictors of response. Compared to the subacute/chronic group, patients with acute brucellosis had a significantly higher frequency of leukopenia (21.2 % vs. 0 %; p < 0.01), elevated C reactive protein (CRP) (76.7 % vs. 52.0 %; p = 0.01), and elevated transaminases (43.8 % vs. 20.0 %; p = 0.025). A significantly higher therapeutic response rate was observed in acute cases (93.2 %) compared to subacute/chronic cases (0.76 %) (p = 0.01). Multivariate analysis identified elevated baseline CRP (OR: 4.00; p = 0.02) and a post-treatment decrease in STA titer (OR: 5.84; p = 0.007) as independent predictors of a favorable therapeutic response. In conclusion, acute brucellosis presents with a more pronounced inflammatory profile than subacute/chronic forms. While patients with acute brucellosis demonstrated a significantly higher therapeutic response rate, the serological response was also more pronounced in this group. Elevated CRP at diagnosis and a significant decrease in STA titer post-treatment are strong, independent predictors of successful outcomes, highlighting their value in patient monitoring.
Severe fever with thrombocytopenia syndrome (SFTS) is a life-threatening tick-borne viral infection with a high mortality rate and limited treatment options. While gastrointestinal symptoms are common, the contribution of gut microbiome disruption to disease progression remains unclear. Previous studies have noted taxonomic shifts in SFTS-associated microbiota, but their functional and metabolic consequences have not been systematically characterized. We conducted an integrated metagenomic and metabolomic analysis of fecal samples from 20 SFTS patients and 20 healthy controls. At the time of admission, patients with SFTS exhibited acute-stage infection, characterized by symptoms such as fever, thrombocytopenia, and gastrointestinal disturbances. Metagenomic sequencing was used to assess the microbial gene content, taxonomic composition, and functional potential. Untargeted metabolomics analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed to profile fecal metabolites. The SFTS patients showed a significantly reduced microbial gene richness, alpha diversity, and compositional stability. Short-chain fatty acid (SCFA)-producing genera (e.g., Faecalibacterium and Roseburia) were depleted, while mucin-degrading and opportunistic taxa (e.g., Pseudomonas and Akkermansia) were enriched. Functionally, biosynthetic and homeostatic pathways were suppressed; while stress-adaptive, biofilm-forming, and virulence-associated pathways were elevated. Metabolomic profiling revealed depletion of anti-inflammatory metabolites (e.g., bile acids and curcumin sulfate) and enrichment of proinflammatory compounds (e.g., porphyrins and beta-tyvelose). Multi-omic correlation highlighted strong links between microbial disruption and altered metabolite production. In conclusion, SFTS is associated with significant alterations in the gut microbiome and its metabolic profile, which is characterized by the loss of beneficial microbial taxa and functions, alongside the emergence of virulence factors and stress-related signatures. These findings underscore the role of microbiome dysfunction in SFTS and suggest that microbiota-targeted strategies may offer supportive benefits, particularly in alleviating SFTS-associated gastrointestinal disturbances and secondary microbial imbalance.
BACKGROUND:Toxoplasmosis, caused by the protozoan Toxoplasma gondii, is a public health problem, especially in congenital infections. Current treatments, with spiramycin or pyrimethamine and sulfadiazine, are highly toxic, prompting the search for effective and safe natural alternatives. OBJECTIVE:This study evaluated the in vitro effect of caffeic acid (CA) on human extravillous trophoblast cells (HTR8/SVneo) infected by T. gondii. METHODS:The microbicidal and metabolic activity of CA against free tachyzoites was analyzed, in addition to its immunological and anti-Toxoplasma action in infected trophoblast cells. RESULTS:The compound was able to reduce the viability of tachyzoites (IC50 5 μg/mL) without any toxicity to the trophoblast cells (CC50 1950 μg/mL); in addition, it reduced the proliferation and infection by tachyzoites at all concentrations tested (5-50 μg/mL). CA also induced changes to the parasite's morphology, including mitochondrial integrity loss, increased production of reactive oxygen species, nitric oxide, exposure to phosphatidylserine and loss of plasmatic membrane integrity, characterizing an apoptosis-like process. Furthermore, there was an increase in interleukins interleukin-1 beta (IL-1β), macrophage migration inhibitory factor (MIF) and transforming growth factor beta (TGF-β) in the T. gondii infected HTR8/SVneo cells. CONCLUSION:CA is a potential candidate for further research aimed at the development of novel therapies for congenital toxoplasmosis.
This study characterizes the alterations in peripheral blood lymphocyte subsets and cytokine levels in patients with respiratory syncytial virus (RSV) infection and evaluates their clinical relevance. We collected clinical data from 215 RSV-positive inpatients. Patients were stratified into distinct groups according to different criteria; within-group comparisons were performed. In the RSV-infected group, absolute counts of all peripheral blood lymphocyte subsets were significantly lower than in controls and showed a negative correlation with disease severity. Conversely, all measured cytokines were markedly elevated in the infected group and positively correlated with the severity of RSV infection. Within the infected group, elderly patients (≥65 years) showed significantly different lymphocyte-subset counts and cytokine profiles compared with non-elderly patients. Similarly, individuals with high-risk diseases exhibited significant differences in these parameters relative to those without such diseases. RSV infection induces abnormalities in peripheral blood lymphocyte subsets and cytokine levels. The magnitude of these immune changes is linked to disease severity, patient age, and selected comorbidities, suggesting their potential utility as adjunct biomarkers for clinical assessment.
Bovine viral diarrhea virus (BVDV) is a major pathogen in cattle, causing significant economic losses and frequently contaminating cell cultures through fetal calf serum, which can compromise biological products. Gene editing technologies, such as CRISPR/Cas9, offer promising tools for developing disease-resistant models. CD46, the primary cellular receptor for BVDV, has an incompletely understood role in viral infection. This study aimed to: (i) characterize and compare CD46 between bovine cell lines resistant (CRIB) and susceptible (MDBK); (ii) edit the BVDV-binding region of MDBK-CD46; and (iii) evaluate the susceptibility of CD46-edited MDBK cells to BVDV infection. CD46 was sequenced in BVDV-sensitive MDBK cells, BVDV-resistant CRIB cells, and bovine fibroblasts. CRISPR/Cas9 was used to delete exon 1 of CD46, which encodes the viral attachment platform. Two guide RNAs were cloned into px458 plasmids expressing GFP and co-transfected into MDBK cells. Genomic DNA was PCR-amplified, cloned, and sequenced. Results showed that CRIB cells express a wild-type CD46 protein, suggesting that CD46 is not responsible for their resistance to BVDV. This resistance is likely due to the truncated ADAM17 in CRIB cells, which may alter membrane composition and endocytic pathways, affecting viral entry. Three edited MDBK cell lines were generated: two with homozygous deletions (A and B), and one with a heteroallelic edit (C). The edited lines A and B exhibited over 90 % resistance to BVDV. These findings support the use of gene editing to generate BVDV-resistant models and to further explore alternative viral receptors and entry pathways.
Exopolysaccharides (EPS) are extracellular metabolites secreted by various bacteria, including lactic acid bacteria (LAB). EPS vary in structure and their composition depends on a number of production factors. In particular, they are used as thickeners to improve the organoleptic properties of foods. In any case, they can also have beneficial effects on human well-being, such as prebiotic effects, antioxidant effects, antimicrobial effects, and modulation of the immune system. This review aims to summarize the results of recent research on EPS produced by LAB in the regulation of intestinal health by acting as prebiotic and antimicrobial agents, as well as their antioxidant, hypocholesterolemic and immunomodulatory effects.
Most studies on Haemophilus influenzae in the course of COPD focus on occurrence of this species in the respiratory tract. However, the relationship between the intestinal microbiota and the respiratory tract, may play a role in the course of COPD. Our study examined the presence of Haemophilus spp. in the oral cavity, respiratory tract and large intestine, and the level of anti-H. influenzae antibodies in patients during acute exacerbations of COPD (AECOPD). An additional goal was to identify the potential microbiota components co-occurring with Haemophilus spp. The study included 35 patients with AECOPD and the control group (23 people). Haemophilus spp. were isolated from 20 % patients in the AECOPD and 17.39 % from the control group, the difference was not statistically significant (p = 0.74). Mean levels of anti-H. influenzae antibodies were 0.491 ± 0.871 μg/ml in the AECOPD group and 1.021 ± 1.421 μg/ml in the control group, the difference was not statistically significant (p = 0.332). Greater diversity within Streptococci and Gram-negative bacilli was found in biological materials from AECOPD. We noted a more common frequency of isolation of Haemophilus spp. from the large intestine of AECOPD, which may indicate the occurrence of gut dysbiosis during exacerbations. The analysis of selected associated species showed that the bacteriological status of a COPD patient may influence the frequency and course of exacerbations.
Influenza A virus (IAV) is a global respiratory pathogen, with macrophages playing a key role in innate immunity. We established mouse models of IAV-induced pneumonia and macrophage depletion, along with an in vitro co-culture system of lung epithelial cells (MLE-12) and macrophages (RAW264.7), to study IAV infection. HE staining, immunohistochemistry, and immunofluorescence revealed IAV-induced lung damage and macrophage recruitment. In the co-culture system, IAV infection caused morphological changes in both cell types, increased viral load, and elevated inflammatory factors. High-throughput sequencing identified miR-1260 and Sema3A-mediated PI3K/AKT/mTOR pathway involvement. Transfection with miRNA mimics, inhibitors, and Sema3A-siRNA showed that miR-1260 exacerbates cell damage by targeting Sema3A via PI3K/AKT/mTOR. Macrophage-depleted mice exhibited worse outcomes (weight loss, inflammation, viral load, pathology) than IAV-infected mice, linked to miR-1260/Sema3A/PI3K/AKT/mTOR regulation. Macrophages protect against IAV by suppressing miR-1260-mediated Sema3A/PI3K/AKT/mTOR activation.
Toxoplasma gondii infection in pregnant females can cause congenital toxoplasmosis. Although maternal and infant immune profiles appear to play a role, studies on this topic are scarce. We analyzed SNPs in the regulatory regions of cytokine genes in 30 mother-newborn pairs, five mothers and two infants with known status, with respect to vertical transmission and the clinical outcome of those infected. Polymorphisms in the IL-2, IL-10, IL-12, IL-17, TNF-α, and TGF-β1 gene promoter or regulatory regions were obtained by sequencing, and genotype and allele frequencies were related to transmission and clinical outcome of the offspring. In children, the polymorphic "G" TNF-α -308 allele, as well as the related low- and high-level homozygous GG or TT genotypes of the 3'UTR region of the IL-12reg gene, were associated with congenital infection. Both cytokines have been shown to be expressed in the cyto- and syncytiotrophoblast; therefore, the fetus might be able to regulate infection at the placental level. In mothers of infected children, the T allele of the IL-12reg 3'UTR gene was associated with more severe disease in their offspring, suggesting that a strong maternal response reduces parasite spread in the fetus. Furthermore, SNPs in the promoter region of IL-2 and TGF-β1 genes were associated with elevated levels and milder disease in children with congenital infection, which is congruent with a regulation of a strong, damaging, inflammatory response. Our results suggest that some up and down regulatory cytokine genes may predispose to vertical transmission or disease severity in congenital toxoplasmosis.
Co-infections involving Pseudomonas aeruginosa and Candida auris are becoming increasingly common in hospitals and represent an emerging clinical challenge, as these pathogens can form mixed biofilms during catheter-associated infections, which complicates treatment, prolongs the disease and poses a significant threat to public health. In this study, we formed individual- and dual-species biofilms with Pseudomonas aeruginosa and Candida auris, and then treated mature biofilms with or without meropenem to determine the number of viable cells (colony-forming units). Moreover, Pseudomonas aeruginosa biofilms plus total or fractionated Candida auris supernatant were exposed to meropenem to calculate biofilm-associated viable cells. The results showed that Pseudomonas aeruginosa exhibits increased survival to meropenem in dual-species biofilms compared to individual-species biofilms. Furthermore, we demonstrated that the molecule that promotes meropenem tolerance is present in the supernatant of Candida auris biofilms with a molecular mass <10 kDa. In conclusion, Candida auris induces meropenem tolerance in Pseudomonas aeruginosa during mixed biofilms.
INTRODUCTION:Oral squamous cell carcinoma (OSCC) exhibits aggressive behavior and poor prognosis. Porphyromonas gingivalis (P. gingivalis) affects the tumor microenvironment, but its role in ferroptosis inhibition in OSCC remains unclear. This study explores the impact of P. gingivalis on ferroptosis through SIRT5 upregulation. MATERIALS AND METHODS:OSCC cell lines (Cal27, SCC9) were treated with the ferroptosis inducer RSL3, with or without P. gingivalis infection. Cell viability, ferroptosis markers (MDA, ROS, GPX4), and cell behavior (proliferation, migration, invasion) were assessed. SIRT5 and downstream targets (IDH2, GCLC) were analyzed using Western blot, qRT-PCR, and immunofluorescence. A SIRT5 knockdown model was used to evaluate its role in ferroptosis resistance. RESULTS:P. gingivalis infection increased OSCC cell survival, reduced ROS and MDA levels, enhanced GPX4 expression, and promoted proliferation, migration, and invasion. Elevated SIRT5 and its targets IDH2 and GCLC were observed. SIRT5 knockdown reversed ferroptosis resistance. CONCLUSION:The findings suggest that P. gingivalis plays a critical role in promoting OSCC malignancy by inhibiting ferroptosis through the upregulation of SIRT5. This highlights the potential of targeting SIRT5 as a therapeutic strategy to counteract the effects of P. gingivalis in OSCC.
Rapid advancements in artificial intelligence (AI) and machine learning (ML) offer significant potential to transform medical microbiology diagnostics, improving pathogen identification, antimicrobial susceptibility prediction and outbreak detection. To address these opportunities and challenges, the ESCMID workshop, "Artificial Intelligence and Machine Learning in Medical Microbiology Diagnostics", was held in Zurich, Switzerland, from June 2-5, 2025. The course featured expert lectures, practical sessions and panel discussions covering foundational ML concepts and deep learning architectures, data interoperability, quality control processes, model development and validation strategies. Key applications discussed included whole-genome sequencing for antimicrobial resistance detection, AI-enhanced digital microscopy automation and MALDI-TOF mass spectrometry-based diagnostics. Participants gained hands-on experience with essential AI tools and platforms. Special emphasis was placed on standardised laboratory protocols, regulatory compliance and ethical considerations, including data governance and patient privacy. Panel sessions further highlighted critical issues of equity, global disparities in AI access, sustainability and environmental impacts related to AI infrastructure. The workshop concluded by underscoring a necessity for ongoing interdisciplinary collaboration, continued education, and substantial investment in equitable AI infrastructure to realise the full potential of AI in clinical diagnostics.
BACKGROUND:While autophagy is pivotal in antimicrobial defense, its regulatory role in Talaromyces marneffei (TM) infected bronchial epithelium remains elusive. OBJECTIVE:To elucidate the impact of TM infection on autophagy in bronchial epithelial cells and to identify the key molecular regulators involved in this process. METHODS:Primary computational screening identified core autophagy modulators. Autophagy flux was monitored through LC3B-II/P62 immunoblotting and transmission electron microscopy. Mechanistic validation was performed using siRNA-mediated FOXO3 silencing, lentivirus-mediated lncSSBP1 knockdown and overexpression cell models, combined with immunofluorescence staining for nuclear localization. RESULTS:Bioinformatics analysis identified seven autophagy modulating effectors, with FOXO3 emerging as the central regulator. Quantitative proteomics revealed biphasic autophagic responses: initial LC3B-II accumulation with P62 degradation at 4h post-infection, followed by P62 rebound at 24h, indicating time-dependent flux impairment. FOXO3 was identified as a critical mediator of TM-induced autophagy. Furthermore, we identified a strong positive correlation between lncSSBP1 and FOXO3 expression, with lncSSBP1 overexpression enhancing FOXO3 levels and promoting autophagosome maturation. CONCLUSION:This study uncovers a previously unrecognized lncRNA-mediated regulatory axis wherein lncSSBP1 orchestrates FOXO3-driven autophagy during TM infection. These results provide new insights into the molecular mechanisms of host-pathogen interactions.
Clostridioides difficile causes severe colitis, which induces neuroinflammation and psychiatric disorder. In a preliminary study, we isolated Clostridium symbiosum from the stools of patients with ulcerative colitis. Therefore, we first examined whether oral infection with C. difficile or C. symbiosum could induce colitis and depression in male mice. Orally gavaged C. difficile or C. symbiosum caused diarrhea, bodyweight loss, depression/anxiety-like behavior, and tumor necrosis factor (TNF)-α and interleukin (IL)-6 overexpression in the colon and hippocampus in the pseudo-germ-free (PGF) and specific germ-free (SPF) mice. However, healthy volunteer microbiota-derived Lactococcus lactis P22 and/or Bifidobacterium longum P26 suppressed C. difficile or C. symbiosum growth and TNF-α expression in macrophage cells. They alleviated C. difficile- or C. symbiosum-induced bodyweight loss, diarrhea, and neurobehavioral changes in PGF and SPF mice, while reducing pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) levels in the colon and in the hippocampus. These findings suggest that C. difficile or C. symbiosum can cause colitis and depression/anxiety. Oral administration of P22 and/or P26 may alleviate gut bacteria-induced gut inflammation and depression/anxiety through the inhibition of their growth and inflammatory response.
