ABSTRACT
Haemophilus influenzae is part of the human nasopharyngeal microbiota and a pathogen causing invasive disease. The extensive genetic diversity observed in H. influenzae necessitates discriminatory analytical approaches to evaluate its population structure. This study developed a core genome multilocus sequence typing (cgMLST) scheme for H. influenzae using pangenome analysis tools and validated the cgMLST scheme using datasets consisting of complete reference genomes (N = 14) and high-quality draft H. influenzae genomes (N = 2297). The draft genome dataset was divided into a development dataset (N = 921) and a validation dataset (N = 1376). The development dataset was used to identify potential core genes, and the validation dataset was used to refine the final core gene list to ensure the reliability of the proposed cgMLST scheme. Functional classifications were made for all the resulting core genes. Phylogenetic analyses were performed using both allelic profiles and nucleotide sequence alignments of the core genome to test congruence, as assessed by Spearman's correlation and ordinary least square linear regression tests. Preliminary analyses using the development dataset identified 1067 core genes, which were refined to 1037 with the validation dataset. More than 70% of core genes were predicted to encode proteins essential for metabolism or genetic information processing. Phylogenetic and statistical analyses indicated that the core genome allelic profile accurately represented phylogenetic relatedness among the isolates (R 2 = 0.945). We used this cgMLST scheme to define a high-resolution population structure for H. influenzae, which enhances the genomic analysis of this clinically relevant human pathogen.
Subject(s)
Genome, Bacterial , Haemophilus influenzae , Multilocus Sequence Typing , Phylogeny , Haemophilus influenzae/genetics , Haemophilus influenzae/classification , Multilocus Sequence Typing/methods , Humans , Haemophilus Infections/microbiology , Genetic VariationABSTRACT
In May 2023, the Detroit Health Department was notified of four cases of invasive nontypeable Haemophilus influenzae (Hi) disease among students attending the same elementary school and grade, all with illness onsets within 7 days. Three patients were hospitalized, and one died. Most U.S. cases of invasive Hi disease are caused by nontypeable strains. No vaccines against nontypeable or non-type b Hi strains are currently available. Chemoprophylaxis is not typically recommended in response to nontypeable Hi cases; however, because of the high attack rate (four cases among 46 students; 8.7%), rifampin prophylaxis was recommended for household contacts of patients with confirmed cases and for all students and staff members in the school wing where confirmed cases occurred. Only 10.8% of students for whom chemoprophylaxis was recommended took it, highlighting gaps in understanding among caregivers and health care providers about persons for whom chemoprophylaxis was recommended. Public health authorities subsequently enhanced communication and education to the school community, improved coordination with health care partners, and established mass prophylaxis clinics at the school. This outbreak highlights the potential for nontypeable Hi to cause serious illness and outbreaks and the need for chemoprophylaxis guidance for nontypeable Hi disease. Achieving high chemoprophylaxis coverage requires education, communication, and coordination with community and health care partners.
Subject(s)
Disease Outbreaks , Haemophilus Infections , Haemophilus influenzae , Schools , Humans , Michigan/epidemiology , Child , Haemophilus influenzae/isolation & purification , Haemophilus Infections/epidemiology , Haemophilus Infections/prevention & control , Male , FemaleABSTRACT
BACKGROUND: Severe asthma (SA) encompasses several clinical phenotypes with a heterogeneous airway microbiome. We determined the phenotypes associated with a low α-diversity microbiome. METHODS: Metagenomic sequencing was performed on sputum samples from SA participants. A threshold of 2 standard deviations below the mean of α-diversity of mild-moderate asthma and healthy control subjects was used to define those with an abnormal abundance threshold as relative dominant species (RDS). FINDINGS: Fifty-one out of 97 SA samples were classified as RDSs with Haemophilus influenzae RDS being most common (n = 16), followed by Actinobacillus unclassified (n = 10), Veillonella unclassified (n = 9), Haemophilus aegyptius (n = 9), Streptococcus pseudopneumoniae (n = 7), Propionibacterium acnes (n = 5), Moraxella catarrhalis (n = 5) and Tropheryma whipplei (n = 5). Haemophilus influenzae RDS had the highest duration of disease, more exacerbations in previous year and greatest number on daily oral corticosteroids. Hierarchical clustering of RDSs revealed a C2 cluster (n = 9) of highest relative abundance of exclusively Haemophilus influenzae RDSs with longer duration of disease and higher sputum neutrophil counts associated with enrichment pathways of MAPK, NF-κB, TNF, mTOR and necroptosis, compared to the only other cluster, C1, which consisted of 7 Haemophilus influenzae RDSs out of 42. Sputum transcriptomics of C2 cluster compared to C1 RDSs revealed higher expression of neutrophil extracellular trap pathway (NETosis), IL6-transignalling signature and neutrophil activation. CONCLUSION: We describe a Haemophilus influenzae cluster of the highest relative abundance associated with neutrophilic inflammation and NETosis indicating a host response to the bacteria. This phenotype of severe asthma may respond to specific antibiotics.
Subject(s)
Asthma , Haemophilus influenzae , Neutrophils , Sputum , Humans , Asthma/microbiology , Haemophilus influenzae/pathogenicity , Haemophilus influenzae/genetics , Sputum/microbiology , Male , Female , Adult , Neutrophils/metabolism , Middle Aged , Phenotype , Haemophilus Infections/microbiologyABSTRACT
BACKGROUND AND OBJECTIVE: COPD and bronchiectasis are common causes of morbidity, particularly around exacerbation. Colonisation with respiratory pathogens can increase the frequency and severity of exacerbations. However, bacterial and viral presence at exacerbation in people with airway colonisation has not been well studied. METHODS: A 6-month cohort study of participants (n = 30) with chronic bronchitis due to bronchiectasis (n = 26) and/or COPD (n = 13) and colonisation with Pseudomonas aeruginosa or Haemophilus influenzae was proven on two sputum cultures at exacerbation in the previous 12 months. Participants were provided self-management education and collected sputum samples daily. Sputum samples at baseline (at least 14 days before or after an exacerbation) and at each exacerbation were examined for a panel of 34 respiratory pathogens using commercially available RT-PCR kits and compared to results obtained using culture methods for the detection of bacteria. RESULTS: Participants provided 29 baseline samples and 71 samples at exacerbation. In 17/29 baseline samples, RT-PCR analysis confirmed the organism demonstrated by culture, while 12 samples showed a discrepancy from culture results. Most exacerbations (57.7%) were not associated with acquiring new bacteria or viruses, while 19.8% showed new bacteria, 15.7% new viruses and 7% both new viruses and bacteria. CONCLUSION: Over half of exacerbations were not associated with new organisms in this cohort of participants with chronic bronchitis and colonisation. However, 26.8% demonstrated a new bacterial species in sputum, which is relevant for antibiotic therapy. Baseline RT-PCR and culture results were discordant in one-third of participants.
Subject(s)
Bronchitis, Chronic , Haemophilus influenzae , Pseudomonas aeruginosa , Pulmonary Disease, Chronic Obstructive , Sputum , Humans , Male , Bronchitis, Chronic/microbiology , Sputum/microbiology , Female , Aged , Middle Aged , Haemophilus influenzae/isolation & purification , Pseudomonas aeruginosa/isolation & purification , Pulmonary Disease, Chronic Obstructive/microbiology , Pulmonary Disease, Chronic Obstructive/complications , Bronchiectasis/microbiology , Bronchiectasis/complications , Cohort Studies , Disease Progression , Pseudomonas Infections/microbiology , Pseudomonas Infections/diagnosis , Pseudomonas Infections/epidemiology , Pseudomonas Infections/complications , Haemophilus Infections/microbiology , Haemophilus Infections/diagnosis , Haemophilus Infections/complications , Haemophilus Infections/drug therapyABSTRACT
Glaesserella parasuis is usually a benign swine commensal in the upper respiratory tract, but virulent strains can cause systemic infection characterized by pneumonia, meningitis, and fibrinous polyserositis. The intensive pulmonary inflammatory response following G. parasuis infection is the main cause of lung injury and death in pigs. Vaccination has failed to control the disease due to the lack of extended cross-protection. Accumulating evidence indicates that the heme-binding protein A (HbpA) is a potential virulence determinant and a promising antigen candidate for the development of a broader range of vaccines. However, it is not yet known whether HbpA contributes to G. parasuis virulence or has any potential immune protective effects against G. parasuis. Here, we show that HbpA can induce the transcription and secretion of proinflammatory cytokines (IL-6, TNF-α, and MCP-1) in porcine alveolar macrophages (PAM, 3D4/31). The HbpA protein is recognized by Toll-like receptors 2 and 4 on 3D4/21 macrophages, resulting in the activation of MAP kinase and NF-κB signalling cascades and the transcription and secretion of proinflammatory cytokines. HbpA contributes to virulence and bacterial pulmonary colonization in C57BL/6 mice and plays a role in adhesion to host cells and evasion of the bactericidal effect of pulmonary macrophages. In addition, mice immunized with HbpA were partially protected against challenge by G. parasuis SC1401. The results suggest that HbpA plays an important role in the pathogenesis of disease caused by G. parasuis and lay a foundation for the development of a subunit or chimeric anti-G. parasuis vaccine.
Subject(s)
Haemophilus Infections , Haemophilus parasuis , NF-kappa B , Signal Transduction , Swine Diseases , Animals , Mice , Haemophilus parasuis/immunology , Haemophilus Infections/veterinary , Haemophilus Infections/prevention & control , Haemophilus Infections/immunology , Haemophilus Infections/microbiology , NF-kappa B/metabolism , Swine Diseases/prevention & control , Swine Diseases/microbiology , Swine Diseases/immunology , Swine , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Pasteurellaceae/immunology , Inflammation/prevention & control , Inflammation/veterinary , FemaleABSTRACT
The Southampton pneumococcal carriage study of children under 5 years old continued during the coronavirus disease 2019 (COVID-19) pandemic. Here, we present data from October 2018 to March 2023 describing prevalence of pneumococci and other pathobionts during the winter seasons before, during, and after the introduction of non-pharmaceutical interventions (NPIs) to prevent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. Nasopharyngeal swabs were collected from children attending outpatient clinics at a secondary care hospital and community healthcare sites. Pre-NPIs, in 2019/2020, the carriage prevalence of pneumococci at the hospital site was 32% (n = 161 positive/499 participants). During NPIs, this fell to 19% (n = 12/64), although based on fewer participants compared to previous years due to COVID-19 restrictions on health-care attendance. In 2021/2022, after NPIs had eased, prevalence rebounded to 33% (n = 15/46) [compared to NPIs period, χ2 (1, N = 110) =2.78, P = 0.09]. Carriage prevalence at community healthcare sites fell significantly from 27% (n = 127/470) in 2019/2020 to 19% during the NPI period (n = 44/228) in 2020/2021 [χ2 (1, N = 698) =4.95, P = 0.026]. No rebound was observed in 2021/2022 [19% (n = 56/288)]. However, in a multivariate logistic regression model, neither site had a significantly lower carriage prevalence during the NPI period compared to the post NPI period. A reduction in serotype diversity was observed in 2020/2021. Carriage of Haemophilus influenzae was particularly affected by NPIs with a significant reduction observed. In conclusion, among children under 5 years of age, transient, modest, and statistically non-significant alterations in carriage of both Streptococcus pneumoniae and H. influenzae were associated with SARS-CoV-2 NPIs.IMPORTANCEStreptococcus pneumoniae (the pneumococcus) continues to be a major contributor to global morbidity and mortality. Using our long-running pediatric study, we examined changes in pneumococcal carriage prevalence in nearly 3,000 children under the age of 5 years between the winters of 2018/2019 and 2022/2023. This period coincided with the severe acute respiratory syndrome coronavirus 2 pandemic and, in particular, the implementation of national strategies to limit disease transmission in the UK. We observed a transient reduction of both Streptococcus pneumoniae and Haemophilus influenzae in these populations during this period of non-pharmaceutical interventions. This aligned with the reduction in invasive pneumococcal disease seen in the UK and is therefore a likely contributor to this phenomenon.
Subject(s)
COVID-19 , Carrier State , Haemophilus Infections , Haemophilus influenzae , Nasopharynx , Pneumococcal Infections , SARS-CoV-2 , Streptococcus pneumoniae , Humans , COVID-19/epidemiology , COVID-19/prevention & control , Child, Preschool , Carrier State/epidemiology , Carrier State/microbiology , SARS-CoV-2/isolation & purification , Pneumococcal Infections/epidemiology , Pneumococcal Infections/prevention & control , Pneumococcal Infections/microbiology , Male , Female , Streptococcus pneumoniae/isolation & purification , Cross-Sectional Studies , Infant , Haemophilus influenzae/isolation & purification , Haemophilus Infections/epidemiology , Haemophilus Infections/prevention & control , Haemophilus Infections/microbiology , Nasopharynx/microbiology , Nasopharynx/virology , United Kingdom/epidemiology , PrevalenceABSTRACT
MicroRNAs (miRNAs) have been shown to play an important regulatory role in the process of pathogenic infection. However, the miRNAs that regulate the pathogenic process of G. parasuis and their functions are still unknown. Here, high-throughput sequencing was used to quantify the expression of miRNA in piglet lung tissue after G. parasuis XX0306 strain infection. A total of 25 differentially expressed microRNAs (DEmiRNAs) were identified. GO and KEGG pathway enrichment analysis showed that many of the functions of genes that may be regulated by DEmiRNA are related to inflammatory response and immune regulation. Further studies found that ssc-miR-135 may promote the expression of inflammatory factors through NF-κB signaling pathway. Whereas, ssc-miR-155-3p inhibited the inflammatory response induced by G. parasuis, and its regulatory mechanism remains to be further investigated. This study provides a valuable reference for revealing the regulatory effects of miRNAs on the pathogenesis of G. parasuis. DATA AVAILABILITY: The datasets generated during the current study are not publicly available due to this study is currently in the ongoing research stage, and some of the data cannot be made public sooner yet, but are available from the corresponding author on reasonable request.
Subject(s)
Haemophilus Infections , Haemophilus parasuis , Inflammation , Lung , MicroRNAs , Swine Diseases , Animals , MicroRNAs/genetics , Swine , Lung/microbiology , Lung/immunology , Swine Diseases/microbiology , Swine Diseases/genetics , Swine Diseases/immunology , Inflammation/genetics , Haemophilus parasuis/genetics , Haemophilus parasuis/pathogenicity , Haemophilus Infections/veterinary , Haemophilus Infections/immunology , Haemophilus Infections/microbiology , Haemophilus Infections/genetics , Gene Expression Profiling , NF-kappa B/metabolism , NF-kappa B/genetics , Signal Transduction , High-Throughput Nucleotide Sequencing , Gene Expression Regulation , Transcriptome , Metastrongyloidea/geneticsABSTRACT
Infection with Glaesserella parasuis, the primary pathogen behind Glässer's disease, is often associated with diverse clinical symptoms, including serofibrinous polyserositis, arthritis, and meningitis. Autophagy plays a dual role in bacterial infections, exerting either antagonistic or synergistic effects depending on the nature of the pathogen. Our previous studies have demonstrated that autophagy serves as a defense mechanism, combating inflammation and invasion caused by infection of highly virulent G. parasuis. However, the precise mechanisms remain to be elucidated. Pathogens exhibit distinct interactions with inflammasomes and autophagy processes. Herein, we explored the effect of autophagy on inflammasomes during G. parasuis infection. We found that G. parasuis infection triggers NLRP3-dependent pro-CASP-1-IL-18/IL-1ß processing and maturation pathway, resulting in increased release of IL-1ß and IL-18. Inhibition of autophagy enhances NLRP3 inflammasome activity, whereas stimulation of autophagy restricts it during G. parasuis infection. Furthermore, assembled NLRP3 inflammasomes undergo ubiquitination and recruit the autophagic adaptor, p62, facilitating their sequestration into autophagosomes during G. parasuis infection. These results suggest that the induction of autophagy mitigates inflammation by eliminating overactive NLRP3 inflammasomes during G. parasuis infection. Our research uncovers a mechanism whereby G. parasuis infection initiates inflammatory responses by promoting the assembly of the NLRP3 inflammasomes and activating NLRP3-CASP-1, both of which processes are downregulated by autophagy. This suggests that pharmacological manipulation of autophagy could be a promising approach to modulate G. parasuis-induced inflammatory responses.
Subject(s)
Autophagy , Caspase 1 , Haemophilus Infections , Haemophilus parasuis , Inflammasomes , NLR Family, Pyrin Domain-Containing 3 Protein , Animals , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , Inflammasomes/immunology , Inflammasomes/metabolism , Haemophilus parasuis/immunology , Haemophilus parasuis/pathogenicity , Haemophilus parasuis/genetics , Caspase 1/metabolism , Caspase 1/genetics , Haemophilus Infections/veterinary , Haemophilus Infections/immunology , Haemophilus Infections/microbiology , Swine , Interleukin-18/metabolism , Interleukin-18/genetics , Interleukin-1beta/metabolism , Interleukin-1beta/genetics , Swine Diseases/microbiology , Swine Diseases/immunology , MiceABSTRACT
Haemophilus influenzae is a human respiratory pathogen and inhabits the human respiratory tract as its only niche. Despite this, the molecular mechanisms that allow H. influenzae to establish persistent infections of human epithelia are not well understood. Here, we have investigated how H. influenzae adapts to the host environment and triggers the host immune response using a human primary cell-based infection model that closely resembles human nasal epithelia (NHNE). Physiological assays combined with dualRNAseq revealed that NHNE from five healthy donors all responded to H. influenzae infection with an initial, 'unproductive' inflammatory response that included a strong hypoxia signature but did not produce pro-inflammatory cytokines. Subsequently, an apparent tolerance to large extracellular and intraepithelial burdens of H. influenzae developed, with NHNE transcriptional profiles resembling the pre-infection state. This occurred in parallel with the development of intraepithelial bacterial populations, and appears to involve interruption of NFκB signalling. This is the first time that large-scale, persistence-promoting immunomodulatory effects of H. influenzae during infection have been observed, and we were able to demonstrate that only infections with live, but not heat-killed H. influenzae led to immunomodulation and reduced expression of NFκB-controlled cytokines such as IL-1ß, IL-36γ and TNFα. Interestingly, NHNE were able to re-activate pro-inflammatory responses towards the end of the 14-day infection, resulting in release of IL-8 and TNFα. In addition to providing first molecular insights into mechanisms enabling persistence of H. influenzae in the host, our data further indicate the presence of infection stage-specific gene expression modules, highlighting fundamental similarities between immune responses in NHNE and canonical immune cells, which merit further investigation.
Subject(s)
Epithelial Cells , Haemophilus Infections , Haemophilus influenzae , Humans , Haemophilus influenzae/immunology , Haemophilus Infections/immunology , Haemophilus Infections/microbiology , Epithelial Cells/microbiology , Epithelial Cells/immunology , Epithelial Cells/metabolism , Nasal Mucosa/microbiology , Nasal Mucosa/immunology , Nasal Mucosa/metabolism , Immune Tolerance , Cells, Cultured , Cytokines/metabolismABSTRACT
Glaesserella parasuis is an important porcine pathogen that commonly colonizes the upper respiratory tract of pigs and is prone to causing Glässer's disease under complex conditions. As yet, the disease has led to serious economic losses to the swine industry worldwide. Studies so far have found that several virulence factors are associated with the pathogenicity of G. parasuis, but the pathogenic mechanism is still not fully understood. Cytolethal distending toxin (CDT), a potential virulence factor in G. parasuis, is involved in cytotoxicity, serum resistance, adherence to and invasion of host cells in vitro. Here, to further investigate the pathogenic role of CDT during G. parasuis infection in vitro and in vivo, a double cdt1 and cdt2 deletion mutant (Δcdt1Δcdt2) without selectable marker was first generated in G. parasuis JS0135 strain by continuous natural transformations and replica plating. Morphological observation and lactate dehydrogenase assay showed that the Δcdt1Δcdt2 mutant was defective in cytotoxicity. Additionally, the Δcdt1Δcdt2 mutant was more susceptible to phagocytosis caused by 3D4/2 macrophages compared to the wild-type JS0135 strain. Moreover, by focusing on clinical signs, necropsy, bacterial recovery and pathological observation, we found that the deletion of cdt1 and cdt2 genes led to a significant attenuation of virulence in G. parasuis. Taken together, these findings suggest that as an important virulence factor, CDT can significantly affect the pathogenicity of G. parasuis.
Subject(s)
Bacterial Toxins , Haemophilus parasuis , Phagocytosis , Swine Diseases , Animals , Swine , Haemophilus parasuis/pathogenicity , Haemophilus parasuis/genetics , Bacterial Toxins/genetics , Bacterial Toxins/toxicity , Bacterial Toxins/metabolism , Swine Diseases/microbiology , Virulence , Haemophilus Infections/veterinary , Haemophilus Infections/microbiology , Haemophilus Infections/immunology , Virulence Factors/genetics , Macrophages/microbiology , Cell LineABSTRACT
To fully understand the safety of DTaP-IPV/Hib vaccination, we evaluated the differences between DTaP-IPV/Hib co-administration and separate administration of the DTaP, IPV and Hib vaccines (DTaP+IPV+Hib) based on adverse events following immunization (AEFI). All AEFI reported in Hebei Province, China, between 2020 and 2022 were included in this study. The risk difference (RD%), relative risk (RR), and Chi-square value were used to compare the differences in reported rates of AEFI between the DTaP-IPV/Hib and DTaP+IPV+Hib groups. From 2020 to 2022, 130 AEFI cases were reported in Hebei Province after DTaP-IPV/Hib vaccination, corresponding to an AEFI reported rate of 66.9/million doses, which was significantly lower than that for DTaP+IPV+Hib (9836 AEFI with a reported rate of 637.8/million doses). The overall reported rate of non-severe AEFI for DTaP+IPV+Hib vaccines was 9.5 times that of DTaP-IPV/Hib vaccination [95% confidence interval (CI): 8.0, 11.3]. Meanwhile, the reported rate of AEFI among infants aged 0-1 y was 9.8 times higher for DTaP+IPV+Hib than for DTaP-IPV/Hib (95% CI: 8.2, 11.7). DTaP+IPV+Hib vaccination also resulted in higher risks of high fever, localized redness and swelling, localized induration, and allergic rash compared with DTaP-IPV/Hib vaccination. The risk of AEFI, which were mostly mild reaction, was higher after vaccination with DTaP+IPV+Hib than after DTaP-IPV/Hib vaccination.
Subject(s)
Diphtheria-Tetanus-Pertussis Vaccine , Haemophilus Vaccines , Poliovirus Vaccine, Inactivated , Vaccines, Combined , Humans , Haemophilus Vaccines/adverse effects , Haemophilus Vaccines/administration & dosage , Poliovirus Vaccine, Inactivated/adverse effects , Poliovirus Vaccine, Inactivated/administration & dosage , Diphtheria-Tetanus-Pertussis Vaccine/adverse effects , Diphtheria-Tetanus-Pertussis Vaccine/administration & dosage , Infant , Vaccines, Combined/adverse effects , Vaccines, Combined/administration & dosage , China/epidemiology , Female , Male , Vaccination/adverse effects , Haemophilus Infections/prevention & control , Immunization Schedule , Drug-Related Side Effects and Adverse Reactions/epidemiology , Diphtheria-Tetanus-acellular Pertussis Vaccines/adverse effects , Diphtheria-Tetanus-acellular Pertussis Vaccines/administration & dosageABSTRACT
BACKGROUND: Myasthenia gravis (MG) is the most common paraneoplastic disorder associated with thymic neoplasms. MG can develop after thymectomy, and this condition is referred to post-thymectomy myasthenia gravis (PTMG). Diffuse panbronchiolitis (DPB), is a rare form of bronchiolitis and is largely restricted to East Asia, has been reported in association with thymic neoplasms. Only three cases of combined MG and DPB have been reported in the literature. CASE PRESENTATION: A 45-year-old Taiwanese woman presented to our hospital with productive cough, rhinorrhea, anosmia, ear fullness, shortness of breath, and weight loss. She had a history of thymoma, and she underwent thymectomy with adjuvant radiotherapy 7 years ago. Chest computed tomography scan revealed diffuse bronchitis and bronchiolitis. DPB was confirmed after video-assisted thoracoscopic surgery lung biopsy, and repeated sputum cultures grew Pseudomonas aeruginosa. She has been on long-term oral azithromycin therapy thereafter. Intravenous antipseudomonal antibiotics, inhaled amikacin, as well as oral levofloxacin were administered. Three months after DPB diagnosis, she developed ptosis, muscle weakness, and hypercapnia requiring the use of noninvasive positive pressure ventilation. MG was diagnosed based on the acetylcholine receptor antibody and repetitive stimulation test results. Her muscle weakness gradually improved after pyridostigmine and corticosteroid therapies. Oral corticosteroids could be tapered off ten months after the diagnosis of MG. She is currently maintained on azithromycin, pyridostigmine, and inhaled amikacin therapies, with intravenous antibiotics administered occasionally during hospitalizations for respiratory infections. CONCLUSIONS: To our knowledge, this might be the first case report of sequential development of DPB followed by PTMG. The coexistence of these two disorders poses a therapeutic challenge for balancing infection control for DPB and immunosuppressant therapies for MG.
Subject(s)
Bronchiolitis , Myasthenia Gravis , Thymectomy , Thymus Neoplasms , Humans , Female , Myasthenia Gravis/etiology , Middle Aged , Bronchiolitis/etiology , Thymectomy/adverse effects , Thymus Neoplasms/surgery , Thymus Neoplasms/complications , Tomography, X-Ray Computed , Haemophilus Infections/etiology , Haemophilus Infections/diagnosis , Thymoma/surgery , Anti-Bacterial Agents/therapeutic use , TaiwanABSTRACT
Immunoglobulin A1 (IgA1) protease is a critical virulence factor of Haemophilus influenzae that facilitates bacterial mucosal infection. This study investigates the effect of iga gene polymorphism on the enzymatic activity of H. influenzae IgA1 protease. The IgA1 protease activity was examined in the H. influenzae Rd KW20 strain and 51 isolates. Genetic variations in iga and deduced amino acid substitutions affecting IgA1 protease activity were assessed. Machine learning tools and functional complementation assays were used to analyze the effects of identified substitutions on the stability and activity of IgA1 protease, respectively. All 51 isolates exhibited similar iga expression levels. No igaB expression was detected. According to comparisons with the reference Rd KW20 strain, four substitutions in the protease domain, 26 in the nonprotease passenger domain, and two in the ß-barrel domain were associated with the change in IgA1 protease activity. No substitutions in the catalytic site of IgA1 protease were observed. Logistic regression, receiver operating characteristic curves, Venn diagrams, and protein stability analyses revealed that the substitutions Asn352Lys, Pro353Ala, Lys356Asn, Gln916Lys, and Gly917Ser, which were located in the nonactive site of the passenger domain, were associated with decreases in IgA1 protease activity and stability, whereas Asn914Lys was associated with an increase in these events. Functional complementation assays revealed that the Asn914Lys substitution increased IgA1 protease activity in the Rd KW20 strain. This study identified substitutions in the nonactive site of the passenger domain that affect both the activity and stability of H. influenzae IgA1 protease.
Subject(s)
Haemophilus influenzae , Haemophilus influenzae/genetics , Haemophilus influenzae/enzymology , Humans , Amino Acid Substitution , Serine Endopeptidases/genetics , Serine Endopeptidases/metabolism , Serine Endopeptidases/chemistry , Immunoglobulin A/metabolism , Haemophilus Infections/microbiology , Haemophilus Infections/immunology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Bacterial Proteins/chemistryABSTRACT
Glaesserella parasuis (G. parasuis) induces vascular damage and systemic inflammation. However, the mechanism by which it causes vascular damage is currently unclear. Baicalin has important anti-inflammatory, antibacterial and immunomodulatory functions. In this study, we explored the ability of baicalin and probenecid to protect against G. parasuis challenge in a piglet model. Sixty piglets were randomly divided into a control group; an infection group; a probenecid group; and 25 mg/kg, 50 mg/kg and 100 mg/kg baicalin groups. The probenecid group and the 25 mg/kg, 50 mg/kg and 100 mg/kg baicalin groups were injected intramuscularly with 20 mg/kg body weight (BW) probenecid and 25 mg/kg BW, 50 mg/kg BW and 100 mg/kg BW baicalin, respectively. All piglets except those from the control group were injected intraperitoneally with 1 × 108 CFU of G. parasuis. The control group was injected intraperitoneally with TSB. The results showed baicalin and probenecid protected piglets against G. parasuis challenge, improved body weight and decreased temperature changes in piglets. Baicalin and probenecid attenuated IL-1ß, IL-10, IL-18, TNF-α and IFN-γ mRNA levels in the blood for 48 h, inhibited the production of the nucleosides ATP, ADP, AMP and UMP from 24 to 72 h, reduced Panx-1/P2Y6/P2X7 expression, weakened NF-kB, AP-1, NLRP3/Caspase-1 and ROCK/MLCK/MLC signalling activation, and upregulated VE-cadherin expression in the blood vessels of piglets challenged with G. parasuis. Baicalin and probenecid alleviated pathological tissue damage in piglets induced by G. parasuis. Our results might provide a promising strategy to control and treat G. parasuis infection in the clinical setting.
Subject(s)
Flavonoids , Haemophilus parasuis , Probenecid , Swine Diseases , Animals , Probenecid/pharmacology , Flavonoids/pharmacology , Flavonoids/administration & dosage , Swine , Swine Diseases/microbiology , Swine Diseases/prevention & control , Haemophilus parasuis/drug effects , Haemophilus Infections/veterinary , Haemophilus Infections/prevention & controlABSTRACT
Gammaherpesviruses are ubiquitous, lifelong pathogens associated with multiple cancers that infect over 95% of the adult population. Increases in viral reactivation, due to stress and other unknown factors impacting the immune response, frequently precedes lymphomagenesis. One potential stressor that could promote viral reactivation and increase viral latency would be the myriad of infections from bacterial and viral pathogens that we experience throughout our lives. Using murine gammaherpesvirus 68 (MHV68), a mouse model of gammaherpesvirus infection, we examined the impact of bacterial challenge on gammaherpesvirus infection. We challenged MHV68 infected mice during the establishment of latency with nontypeable Haemophilus influenzae (NTHi) to determine the impact of bacterial infection on viral reactivation and latency. Mice infected with MHV68 and then challenged with NTHi, saw increases in viral reactivation and viral latency. These data support the hypothesis that bacterial challenge can promote gammaherpesvirus reactivation and latency establishment, with possible consequences for viral lymphomagenesis.
Subject(s)
Haemophilus Infections , Haemophilus influenzae , Herpesviridae Infections , Virus Activation , Virus Latency , Animals , Haemophilus influenzae/physiology , Mice , Herpesviridae Infections/virology , Haemophilus Infections/microbiology , Haemophilus Infections/virology , Gammaherpesvirinae/physiology , Disease Models, Animal , Mice, Inbred C57BL , Rhadinovirus/physiology , FemaleABSTRACT
Asthma is a chronic and heterogeneous disease affecting the lungs and respiratory tract. In particular, the neutrophil subtype of asthma was described as persistent, more severe, and corticosteroid-resistant. Growing evidence suggested that nontypeable Haemophilus influenzae (NTHi) infection contributes to the development of neutrophilic asthma, exacerbating clinical symptoms and increasing the associated medical burden. In this work, arginine-grafted chitosan (CS-Arg) was ionically cross-linked with tris(2-carboxyethyl) phosphine (TCEP), and a highly-efficient antimicrobial agent, poly-ε-L-Lysine (ε-PLL), was incorporated to prepare ε-PLL/CS-Arg/TCEP (ECAT) composite nanogels. The results showed that ECAT nanogels exhibited highly effective inhibition against the proliferation of NTHi, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). In addition, ECAT nanogels could effectively inhibit the formation of mucins aggregates in vitro, suggesting that the nanogel might have the potential to destroy mucin in respiratory disease. Furthermore, in the ovalbumin (OVA)/NTHi-induced Balb/c mice model of neutrophilic asthma, the number of neutrophils in the alveolar lavage fluid and the percentage of inflammatory cells in the blood were effectively reduced by exposure to tower nebulized administration of ECAT nanogels, and reversing airway hyperresponsiveness (AHR) and reducing inflammation in neutrophilic asthma mice. In conclusion, the construction of ECAT nanogels was a feasible anti-infective and anti-inflammatory therapeutic strategy, which demonstrated strong potential in the clinical treatment of neutrophilic asthma.
Subject(s)
Anti-Bacterial Agents , Asthma , Chitosan , Escherichia coli , Mice, Inbred BALB C , Neutrophils , Staphylococcus aureus , Animals , Staphylococcus aureus/drug effects , Asthma/drug therapy , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Neutrophils/drug effects , Chitosan/administration & dosage , Chitosan/chemistry , Escherichia coli/drug effects , Female , Haemophilus influenzae/drug effects , Nanogels/chemistry , Ovalbumin/administration & dosage , Mucins , Polylysine/chemistry , Polylysine/administration & dosage , Haemophilus Infections/drug therapy , Mice , Polyethyleneimine/chemistry , Polyethyleneimine/administration & dosage , GelsABSTRACT
Glaesserella parasuis (G. parasuis) causes serious inflammation and meningitis in piglets. Quercetin has anti-inflammatory and anti-bacterial activities; however, whether quercetin can alleviate brain inflammation and provide protective effects during G. parasuis infection has not been studied. Here, we established a mouse model of G. parasuis infection in vivo and in vitro to investigate transcriptome changes in the mouse cerebrum and determine the protective effects of quercetin on brain inflammation and blood-brain barrier (BBB) integrity during G. parasuis infection. The results showed that G. parasuis induced brain inflammation, destroyed BBB integrity, and suppressed PI3K/Akt/Erk signaling-pathway activation in mice. Quercetin decreased the expression of inflammatory cytokines (Il-18, Il-6, Il-8, and Tnf-α) and BBB-permeability marker genes (Mmp9, Vegf, Ang-2, and Et-1), increased the expression of angiogenetic genes (Sema4D and PlexinB1), reduced G. parasuis-induced tight junction disruption, and reactivated G. parasuis-induced suppression of the PI3K/Akt/Erk signaling pathway in vitro. Thus, we concluded that quercetin may protect BBB integrity via the PI3K/Akt/Erk signaling pathway during G. parasuis infection. This was the first attempt to explore the protective effects of quercetin on brain inflammation and BBB integrity in a G. parasuis-infected mouse model. Our findings indicated that quercetin is a promising natural agent for the prevention and treatment of G. parasuis infection.
Subject(s)
Blood-Brain Barrier , Disease Models, Animal , MAP Kinase Signaling System , Phosphatidylinositol 3-Kinases , Proto-Oncogene Proteins c-akt , Quercetin , Animals , Blood-Brain Barrier/drug effects , Blood-Brain Barrier/metabolism , Quercetin/pharmacology , Mice , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , MAP Kinase Signaling System/drug effects , Meningitis/microbiology , Meningitis/drug therapy , Meningitis/metabolism , Haemophilus Infections/drug therapy , Haemophilus Infections/microbiology , Signal Transduction/drug effects , Haemophilus parasuis/drug effects , Haemophilus parasuis/pathogenicity , Cytokines/metabolism , SwineABSTRACT
Haemophilus influenzae serotype a (Hia) has recently emerged as an important cause of invasive disease in the North American Arctic and Sub-Arctic regions, mainly affecting young Indigenous children. In this study, we addressed the question of whether the prevalence of Hia and all H. influenzae in the nasopharynx differed between paediatric populations from regions with high versus low incidence of invasive Hia disease. Nasopharyngeal specimens from children with acute respiratory tract infections (ARTI) collected for routine diagnostic detection of respiratory viruses were analysed with molecular-genetic methods to identify and serotype H. influenzae. In Nunavut, a region with a high incidence of invasive Hia disease, all H. influenzae and particularly Hia were found in the nasopharynx of 60.6% and 3.0% children. In Southern Ontario (Hamilton region), where Hia invasive disease is rare, the frequencies of all H. influenzae and Hia detection were 38.5% and 0.6%, respectively. In both cohorts, non-typeable H. influenzae was prevalent (57.0% and 37.9%, respectively). Considering that Hia is an important cause of severe invasive disease in Nunavut children, 3% prevalence of Hia among children with ARTI can reflect continuing circulation of the pathogen in the Northern communities that may result in invasive disease outbreaks.
Subject(s)
Haemophilus Infections , Haemophilus influenzae , Nasopharynx , Humans , Haemophilus influenzae/isolation & purification , Haemophilus Infections/epidemiology , Child, Preschool , Nasopharynx/microbiology , Prevalence , Infant , Male , Female , Incidence , Ontario/epidemiology , Child , Arctic Regions/epidemiology , Nunavut/epidemiology , Respiratory Tract Infections/epidemiology , Respiratory Tract Infections/microbiology , Canada/epidemiology , SerogroupABSTRACT
Glycoconjugate vaccines are based on chemical conjugation of pathogen-associated carbohydrates with immunogenic carrier proteins and are considered a very cost-effective way to prevent infections. Most of the licensed glycoconjugate vaccines are composed of saccharide antigens extracted from bacterial sources. However, synthetic oligosaccharide antigens have become a promising alternative to natural polysaccharides with the advantage of being well-defined structures providing homogeneous conjugates. Haemophilus influenzae (Hi) is responsible for a number of severe diseases. In recent years, an increasing rate of invasive infections caused by Hi serotype a (Hia) raised some concern, because no vaccine targeting Hia is currently available. The capsular polysaccharide (CPS) of Hia is constituted by phosphodiester-linked 4-ß-d-glucose-(1â4)-d-ribitol-5-(PO4â) repeating units and is the antigen for protein-conjugated polysaccharide vaccines. To investigate the antigenic potential of the CPS from Hia, we synthesized related saccharide fragments containing up to five repeating units. Following the synthetic optimization of the needed disaccharide building blocks, they were assembled using the phosphoramidite approach for the installation of the phosphodiester linkages. The resulting CPS-based Hia oligomers were conjugated to CRM197 carrier protein and evaluated inâ vivo for their immunogenic potential, showing that all glycoconjugates were capable of raising antibodies recognizing Hia synthetic fragments.
Subject(s)
Glycoconjugates , Haemophilus influenzae , Glycoconjugates/chemistry , Glycoconjugates/immunology , Glycoconjugates/chemical synthesis , Haemophilus influenzae/immunology , Haemophilus influenzae/chemistry , Animals , Vaccines, Conjugate/chemistry , Vaccines, Conjugate/immunology , Mice , Haemophilus Vaccines/immunology , Haemophilus Vaccines/chemistry , Bacterial Proteins/immunology , Bacterial Proteins/chemistry , Haemophilus Infections/prevention & control , Haemophilus Infections/immunologyABSTRACT
Whether cross-infection of respiratory pathogens between patients with non-cystic fibrosis bronchiectasis occurs is debated. Investigation with traditional microbiological culture risks simplifying the lung microbiome. We demonstrate the use of culture-independent Multilocus sequence typing to screen for Haemophilus influenzae strain types in a cohort of twenty-eight patients with non-cystic fibrosis bronchiectasis.