Pathogens最新文献

Influenza A viruses constantly threaten the global population, with seasonal outbreaks occurring in different parts of the world, including avian influenza. Severe influenza A virus infections are strongly associated with the cytokine storm, which can contribute significantly to morbidity and even mortality. The virulence and high mutability of these viruses necessitate more effective treatment strategies and regimens to manage patients, especially those with a severe disease. Favipiravir is an antiviral agent approved in Japan for treating influenza virus strains resistant to the current antivirals. The objective of this study is to investigate the combination treatment of Favipiravir paired with selected repurposed drugs to determine the effectiveness of these combinations against influenza A virus replication as well as their effects on cytokine expression. Specific combinations of Favipiravir with Doxycycline, Azithromycin or Ivermectin were identified to be highly synergistic and effective in inhibiting live virus titers of an influenza H3N2 clinical strain by 4 log₁₀. Furthermore, combinations of Favipiravir with Doxycycline or Azithromycin also exhibited immunomodulatory effects on pro-inflammatory cytokines by strongly reducing the relative mRNA expression of IFN-γ, IL-6, TNF-α and IL-1β. Notably, monotherapy with Andrographolide also completely inhibited influenza virus titers by 4 log₁₀. Specific combinations of Favipiravir with Artesunate or Andrographolide revealed additive effects by inhibiting influenza virus titers by about 2 or 1.5 log₁₀, respectively. Our findings indicate that specific drug combinations show promising efficacy and potential in the treatment of influenza and warrant further studies using influenza models of human cell, tissue and animal infection.

Metabolic Dysfunction-Associated Steato-Hepatitis (MASH) is a multiple-hit disease. Endotoxins, ethanol, and other metabolites of certain gut microbiota can reach the liver and accelerate inflammation and disease progression. Targeting ethanol-producing colonic bacteria with rifaximin could affect the progress of MASH. In the present study, thirty mice were assigned to three groups (n = 10 mice per group). Mice received either a normal diet, a Western diet, or a Western diet with oral rifaximin. After 12 weeks, liver function, serum levels of TNF-α, interleukin (IL)-1β, IL-6, and lipopolysaccharides (LPS) were measured. Liver specimens were assessed for pathological changes, lipid deposition, and fibrosis. Expression of p53, GFAP, CD68, and TLR-4 in the liver was also assessed. Faecal samples were evaluated for ethanol contents. Lactobacillus acidophilus, in addition to ethanol-producing Klebsiella pneumoniae and Escherichia coli, were isolated, quantified, and tested for sensitivity to rifaximin. Rifaximin was able to ameliorate Western diet-induced biochemical changes and elevated TNF-α, IL-1β, IL-6, and LPS levels. Changes in liver histology, fibrosis, and lipid content were attenuated. Expressions of p53, GFAP, CD68, and TLR-4 in the liver were all reduced. The Western diet-induced increases in faecal ethanol or ethanol-producing bacteria were not corrected by rifaximin. After 12 weeks, isolated bacteria from the rifaximin group were rifaximin-resistant. Our findings imply that the protective impact of rifaximin in the MASH model is unlikely to be mediated by alteration of ethanol-producing colonic bacteria because of acquired rifaximin resistance. Rifaximin-induced reduction in endotoxemia and inflammation in the liver appears to be a more relevant explanation.

PIM kinases (PIM1, PIM2, PIM3) are serine/threonine kinases implicated in infection and reactivation of various viruses, but their roles in HIV-1 gene expression and particle production remain unclear. We examined their impact on HIV-1 and related viruses using co-transfection systems. PIM1 and PIM3, but not PIM2, markedly suppressed HIV-1 virion production without affecting infectivity. This inhibitory effect extended to transmitted/founder HIV-1 clones and SIV, indicating broad activity across lentiviruses. Kinase-dead mutants failed to reduce virion production, confirming the requirement for catalytic activity. Our data suggest that PIM1 and PIM3 act at distinct steps of HIV-1 gene expression: PIM1 reduces transcription, whereas PIM3 acts post-transcriptionally to diminish viral protein expression. Co-expression of PIM1 and PIM3 further enhanced suppression, suggesting complementary functions. Both kinases also inhibited expression from non-LTR promoters, implying involvement of general cellular factors. These findings reveal distinct and cooperative actions of PIM1 and PIM3 in limiting HIV-1 particle production, providing new insights into host kinase-mediated regulation of viral gene expression.

Bacillus anthracis displays susceptibility to penicillin despite harboring a β-lactamase gene, a phenotype governed by the anti-sigma factor RsiP. While RsiP represses σ^P-dependent β-lactamase expression, its broader roles in physiology and virulence remain unclear. This study aimed to define the global regulatory functions of RsiP beyond antibiotic resistance. Deletion of rsiP significantly upregulated the nprR gene, which is an important quorum-sensing (QS) system regulator and enhanced protease secretion. The ΔrsiP mutant caused higher mortality in cellular and Galleria mellonella models and triggered elevated inflammatory cytokines (IL-6, IL-1β, TNF-α, MIP-2) in macrophages models. Surprisingly, in DBA/2 mice models, ΔrsiP was attenuated, with increased host survival and reduced bacterial loads. Competitive indices (CI) confirmed fitness defects in mice (spleen CI = 0.39; liver CI = 0.42). These defects were not due to altered oxidative stress tolerance but were attributed to impaired macrophage internalization of ΔrsiP spores, reducing early colonization. Our findings indicate that RsiP not only modulates β-lactam resistance but also influences extracellular protease activity and host adaptation.

Gram-negative (GN) periprosthetic joint infections (PJIs) are being increasingly reported. However, the role of Klebsiella species in PJIs remains unclear. Therefore, we aimed to analyze the prevalence, clinical presentation, microbial spectrum, antibiogram, treatment strategies and outcomes of Klebsiella-associated PJIs. A total of 1925 culture-positive total joint revision arthroplasties (rTJA) were retrospectively reviewed at a single center. Patient data were extracted from our institutional arthroplasty and PJI database. We identified 20 Klebsiella-positive PJIs (hip/knee, 11/9), representing 1.0% of all culture-positive rTJAs. The cases were predominantly polymicrobial (80%) and chronic (50%). Notably, Klebsiella spp. was rarely detected as an initial infectious event but was predominantly identified in the context of revision or re-revision procedures, frequently in patients with prior or persistent PJIs. Klebsiella pneumoniae was the most frequent species, with 44% showing multi-drug resistance. The antimicrobial susceptibility of Klebsiella isolates showed high resistance to cephalosporines and penicillin, in contrast little to no resistance to meropenem, gentamicin and levofloxacin. The most common initial surgical intervention was a two-stage revision (65%). Infection control (Tier 1) was observed in 11%, while further intervention was needed in 56% (Tier 3). All patients who had already died were classified as Tier 4 (33%). Klebsiella spp. was detected in 10.0% of GN rTJAs and was mainly associated with complex revision settings rather than primary infections. It is often associated with chronic polymicrobial infections and high antimicrobial resistance. The outcomes were generally poor, highlighting the need for pathogen-specific treatment strategies and improved diagnostics.

This study was conducted to investigate tick species that may harbour severe fever with thrombocytopenia syndrome virus (SFTSV) and Babesia microti in the provinces of Henan, Anhui, and Zhejiang, as well as in Shanghai in the central and eastern parts of China. Between March and September 2023, 721 pools of ticks were collected belonging to three genera and five species: Haemaphysalis longicornis (n = 612; 84.9%), Haemaphysalis fusca (n = 94; 13.0%), Rhipicephalus microplus (n = 10; 1.4%), Amblyomma testudinarium (n = 3; 0.4%), and Haemaphysalis wellingtoni (n = 2; 0.3%). The SFTSV-positive pool rate was 20.0%, 13.0%, 5.8%, and 4.1% in Xinyang, Henan; Songjiang, Shanghai; Lu'an, Anhui; and Zhoushan, Zhejiang, respectively. SFTSV was detected in all five tick species collected. Among the SFTSV-positive pools, H. longicornis constituted the highest proportion (83.9%, 78/93), whereas pools containing R. microplus and H. wellingtoni each represented the lowest proportion (1.1%, 1/93). Babesia microti was assayed only in these SFTSV-positive tick pools, and co-infection was found in both H. longicornis and H. wellingtoni, though it was most frequent in H. longicornis.

Scrub typhus, caused by Orientia tsutsugamushi, remains a neglected cause of acute febrile illness. Molecular testing of blood supports early diagnosis, yet once doxycycline is started, blood qPCR positivity can drop rapidly, complicating short-term follow-up and relapse surveillance. We compared detection across multiple clinical specimens and evaluated nasopharyngeal swabs (NPSs) as noninvasive supplementary specimens during treatment initiation. In a prospective single-center cohort from Hainan, China, we enrolled 20 patients with scrub typhus. Blood, NPS, urine, and stool were collected before doxycycline administration 24 h after the first dose and on day 5. qPCR was performed for the analysis of Orientia tsutsugamushi. qPCR-positive specimens were subjected to nested PCR targeting TSA56, and nested PCR-positive amplicons were Sanger sequenced for genotyping. Before treatment, O. tsutsugamushi DNA was detected in 15/20 blood samples (75.00%) and 5/20 NPS samples (25.00%), but 0/20 urine samples (0%) and 0/20 stool samples (0%). At 24 h after treatment, detection in blood was 0/20 (0%) while NPS samples were positive in 3/20 (15.00%). All specimens were negative by day 5 after treatment. Across sequenced NPS positives (n = 3), Karp 2/3 (66.77%) and Gilliam 1/3 (33.33%) predominated. In paired blood-NPS positives, inter-specimen homology was high (percentage nucleotide identity 100% for Karp and 100% for Gilliam). NPS is not sensitive enough for primary diagnosis; however, within the first 24 h after doxycycline it offers a practical, noninvasive supplementary specimen to support short-term follow-up and community-based sampling when venipuncture or transport are constrained. Larger, multi-center studies are warranted to refine sampling windows and diagnostic performance.

Varicella-Zoster Virus (VZV) is one of the most important pathogens in ophthalmology. Reactivation may involve the adnexa (blepharoconjunctivitis, pseudomembranous conjunctivitis), cornea (dendritic keratitis, nummular and necrotizing stromal keratitis, disciform endotheliitis, neurotrophic ulcers, mucous-plaque keratitis) and sclera (episcleritis, anterior scleritis). Uveal inflammation ranges from anterior uveitis-with iris atrophy, trabeculitis-induced glaucoma and complicated cataract-to posterior necrotizing syndromes: acute retinal necrosis in immunocompetent hosts and progressive outer retinal necrosis in immunosuppressed patients, often complicated by occlusive vasculitis, macular edema, retinal detachment and phthisis. Optic nerve and cranial nerve involvement (optic neuritis, neuroretinitis, III/IV/VI palsies) and orbital inflammation may occur even without cutaneous signs ("zoster sine herpete"), making PCR-based intraocular diagnostics essential. Management relies on early, high-dose antivirals (acyclovir or valacyclovir), judicious corticosteroids and timely surgical intervention when required. Universal childhood varicella vaccination and recombinant zoster vaccination in adults ≥50 years have reduced VZV incidence and ocular complications in settings with high vaccine coverage, though rare post-vaccine keratitis or uveitis underscore the need for ongoing vigilance. In this review, we synthesize current knowledge on varicella-zoster virus ocular disease, with a focus on host-pathogen interactions that drive both injury and defense.

Antimicrobial Resistance (AMR) is a critical public health challenge requiring a coordinated One Health approach. Escherichia coli is a key indicator of AMR and fecal contamination, as well as a zoonotic pathogen transmissible from animals to humans, often through contaminated products like meat and eggs. This study assessed the presence of antibiotic-resistant E. coli and associated resistance genes in 248 cloacal/eggshell samples collected from four autochthonous Portuguese laying hen breeds (Preta Lusitânica, Amarela, Branca, and Pedrês Portuguesa) raised under low antibiotic exposure. A total of 81 E. coli isolates were analyzed for phenotypic antibiotic susceptibility (EUCAST/CLSI) and genotypic resistance, using PCR. Resistance to at least one antibiotic was observed in 98.0% of the isolates. Gentamicin resistance was particularly high (97.1% cloacal; 95.7% eggshell isolates), followed by tetracycline (31.0% cloacal; 41.0% eggshell) and ampicillin (14.0% cloacal; 24.0% eggshell). Multidrug resistance (MDR) was observed in 14.3% of cloacal and 17.4% of eggshell isolates. Notably, no resistance was found against critically important antibiotics. The most prevalent resistance genes were sul2 (45.0% cloacal; 48.0% eggshell) and bla_TEM (45.0% cloacal; 36.0% eggshell). Detection of resistant and MDR E. coli in low input systems suggests environmental acquisition, with chickens as reservoirs, highlighting the need for One Health surveillance.

Mycoplasma bovis (M. bovis) is a major pathogen responsible for bovine respiratory disease, mastitis, and arthritis, causing significant economic losses to the cattle industry worldwide. To elucidate the genetic and biological characteristics of M. bovis circulating in Yunnan Province, China, twenty PCR-positive bovine respiratory samples were collected from cattle farms in Kunming; three isolates-M.bo-YNXD-1, A1, and A8-were successfully cultured and identified through colony morphology, biochemical assays, and molecular characterization. Antimicrobial susceptibility testing showed that M.bo-YNXD-1 exhibited multidrug resistance to six antibiotics, including ciprofloxacin and lincomycin, while A1 and A8 were resistant to one or two agents, respectively. Multilocus sequence typing (MLST) analysis revealed that isolates M.bo-YNXD-1 and M.bo-YNXD-A8 belonged to sequence type ST52, whereas isolate M.bo-YNXD-A1 was assigned to ST90, indicating the coexistence of distinct genetic lineages in this region. Virulence gene screening showed that isolate M.bo-YNXD-A8 was positive for VspX and p81, whereas all three isolates were positive for p48 and Vpam. A SYBR Green I-based quantitative PCR (qPCR) assay targeting the oppD/F gene was established, exhibiting high specificity, a detection limit of 10 copies/μL, and intra-/inter-assay variation below 3%. Validation using clinical samples demonstrated superior sensitivity compared with conventional PCR. Taken together, these findings indicate the presence of distinct MLST genotypes and virulence-associated genetic heterogeneity among regional Mycoplasma bovis isolates, and introduce a rapid, sensitive, and reliable qPCR assay for early detection and epidemiological surveillance. This study provides critical insights for rational antimicrobial use and targeted control strategies against M. bovis infections.