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MBio May 2024species that cause respiratory infections in mammals include , which causes human whooping cough, and , which infects nearly all mammals. Both bacterial species produce...
species that cause respiratory infections in mammals include , which causes human whooping cough, and , which infects nearly all mammals. Both bacterial species produce filamentous hemagglutinin (FhaB) and adenylate cyclase toxin (ACT), prominent surface-associated and secreted virulence factors that contribute to persistence in the lower respiratory tract by inhibiting clearance by phagocytic cells. FhaB and ACT proteins interact with themselves, each other, and host cells. Using immunoblot analyses, we showed that ACT binds to FhaB on the bacterial surface before it can be detected in culture supernatants. We determined that SphB1, a surface protease identified based on its requirement for FhaB cleavage, is also required for ACT cleavage, and we determined that the presence of ACT blocks SphB1-dependent and -independent cleavage of FhaB, but the presence of FhaB does not affect SphB1-dependent cleavage of ACT. The primary SphB1-dependent cleavage site on ACT is proximal to ACT's active site, in a region that is critical for ACT activity. We also determined that FhaB-bound ACT on the bacterial surface can intoxicate host cells producing CR3, the receptor for ACT. In addition to increasing our understanding of FhaB, ACT, and FhaB-ACT interactions on the surface, our data are consistent with a model in which FhaB functions as a novel toxin delivery system by binding to ACT and allowing its release upon binding of ACT to its receptor, CR3, on phagocytic cells.IMPORTANCEBacteria need to control the variety, abundance, and conformation of proteins on their surface to survive. Members of the Gram-negative bacterial genus include , which causes whooping cough in humans, and , which causes respiratory infections in a broad range of mammals. These species produce two prominent virulence factors, the two-partner secretion (TPS) effector FhaB and adenylate cyclase toxin (ACT), that interact with themselves, each other, and host cells. Here, we determined that ACT binds FhaB on the bacterial surface before being detected in culture supernatants and that ACT bound to FhaB can be delivered to eukaryotic cells. Our data are consistent with a model in which FhaB delivers ACT specifically to phagocytic cells. This is the first report of a TPS system facilitating the delivery of a separate polypeptide toxin to target cells and expands our understanding of how TPS systems contribute to bacterial pathogenesis.
Topics: Adenylate Cyclase Toxin; Phagocytes; Virulence Factors, Bordetella; Humans; Bordetella pertussis; Adhesins, Bacterial; Bordetella bronchiseptica; Protein Binding; Animals
PubMed: 38534159
DOI: 10.1128/mbio.00632-24 -
The Journal of Infection Apr 2024
Topics: Humans; Whooping Cough; China; Pertussis Vaccine; Bordetella pertussis
PubMed: 38513738
DOI: 10.1016/j.jinf.2024.106140 -
MSystems Apr 2024The regulation of virulence is mediated by the two-component system BvgA/S, which activates the transcription of virulence-activated genes (s). In the avirulent phase,...
The regulation of virulence is mediated by the two-component system BvgA/S, which activates the transcription of virulence-activated genes (s). In the avirulent phase, the s are not expressed, but instead, virulence-repressed genes (s) are expressed, under the control of another two-component system, RisA/K. Here, we combined transcriptomic and chromatin immunoprecipitation sequencing (ChIPseq) data to examine the RisA/K regulon. We performed RNAseq analyses of RisA-deficient and RisA-phosphoablative mutants cultivated in virulent and avirulent conditions. We confirmed that the expression of most s is regulated by phosphorylated RisA. However, the expression of some, including those involved in flagellum biosynthesis and chemotaxis, requires RisA independently of phosphorylation. Many RisA-regulated genes encode proteins with regulatory functions, suggesting multiple RisA regulation cascades. By ChIPseq analyses, we identified 430 RisA-binding sites, 208 within promoter regions, 201 within open reading frames, and 21 in non-coding regions. RisA binding was demonstrated in the promoter regions of most s and, surprisingly, of some s, as well as for other genes not identified as s or s. Unexpectedly, many genes, including some s, like , , and , contain a BvgA-binding site and a RisA-binding site, which increases the complexity of the RisAK/BvgAS network in virulence regulation.IMPORTANCEThe expression of virulence-activated genes (s) of , the etiological agent of whooping cough, is under the transcriptional control of the two-component system BvgA/S, which allows the bacterium to switch between virulent and avirulent phases. In addition, the more recently identified two-component system RisA/K is required for the expression of genes, collectively named s, that are repressed during the virulent phase but activated during the avirulent phase. We have characterized the RisA/K regulon by combined transcriptomic and chromatin immunoprecipitation sequencing analyses. We identified more than 400 RisA-binding sites. Many of them are localized in promoter regions, especially s, but some were found within open reading frames and in non-coding regions. Surprisingly, RisA-binding sites were also found in promoter regions of some s, illustrating the previously underappreciated complexity of virulence regulation in .
Topics: Humans; Bordetella pertussis; Regulon; Transcription Factors; Whooping Cough; Bacterial Proteins; Chromatin Immunoprecipitation Sequencing; Gene Expression Profiling
PubMed: 38470037
DOI: 10.1128/msystems.00951-23 -
The Pan African Medical Journal 2023Pertussis is a real public health problem due to high neonatal morbidity rates and resurgence despite high vaccination coverage. The purpose of this study is to analyze...
Pertussis is a real public health problem due to high neonatal morbidity rates and resurgence despite high vaccination coverage. The purpose of this study is to analyze the epidemiological profile of pertussis in infants hospitalized from 2012 to 2019. We conducted a retrospective, descriptive study over a 7-year and 8-month period from January 2012 to July 2019. It involved 500 infants admitted with clinical suspicion of pertussis. The average age of infants was 72 days, ranging from 28 days to 18 months; 75% of infants were less than 3 months old. The peak incidence was registered in 2012 and 2016, with a summer predominance (32%); 460 infants (92%) were not or incompletely vaccinated, 42.2% of whom were too young to be vaccinated. A probable contaminant in the entourage was found in 43,6% of cases. Whooping cough and cyanosis were the main reason for hospitalization (77.6%). Chest radiography objectified bronchial disease (25,4%) and alveolar foci (22.7%). Blood count performed in 410 infants showed hyperlymphocytosis in 67.5% of cases. Polymerase chain reaction (PCR) on nasopharyngeal sample collected from 206 infants was positive for Bordetella pertussis in 64% of cases; 118 PCR performed in mothers were positive in 47.7% of cases. All infants received Clarithromycin. Pertussis is a major cause of morbidity in infants in Casablanca. The prevention strategy is based on vaccination of family members of infants. However, vaccination of pregnant women appears to be more effective.
Topics: Infant; Infant, Newborn; Humans; Female; Pregnancy; Whooping Cough; Retrospective Studies; Bordetella pertussis; Mothers; Vaccination
PubMed: 38465012
DOI: 10.11604/pamj.2023.46.124.42073 -
Nature Communications Mar 2024Many countries continue to experience pertussis epidemics despite widespread vaccination. Waning protection after booster vaccination has highlighted the need for a...
Many countries continue to experience pertussis epidemics despite widespread vaccination. Waning protection after booster vaccination has highlighted the need for a better understanding of the immunological factors that promote durable protection. Here we apply systems vaccinology to investigate antibody responses in adolescents in the Netherlands (N = 14; NL) and the United Kingdom (N = 12; UK) receiving a tetanus-diphtheria-acellular pertussis-inactivated poliovirus (Tdap-IPV) vaccine. We report that early antiviral and interferon gene expression signatures in blood correlate to persistence of pertussis-specific antibody responses. Single-cell analyses of the innate response identified monocytes and myeloid dendritic cells (MoDC) as principal responders that upregulate antiviral gene expression and type-I interferon cytokine production. With public data, we show that Tdap vaccination stimulates significantly lower antiviral/type-I interferon responses than Tdap-IPV, suggesting that IPV may promote antiviral gene expression. Subsequent in vitro stimulation experiments demonstrate TLR-dependent, IPV-specific activation of the pro-inflammatory p38 MAP kinase pathway in MoDCs. Together, our data provide insights into the molecular host response to pertussis booster vaccination and demonstrate that IPV enhances innate immune activity associated with persistent, pertussis-specific antibody responses.
Topics: Adolescent; Humans; Bordetella pertussis; Immunity, Humoral; Tetanus; Whooping Cough; Diphtheria; Vaccines, Combined; Antibodies, Bacterial; Diphtheria-Tetanus-acellular Pertussis Vaccines; Poliovirus Vaccine, Inactivated; Vaccination; Immunization, Secondary; Corynebacterium; Poliovirus; Interferons; Antiviral Agents
PubMed: 38459022
DOI: 10.1038/s41467-024-46560-w -
Journal of Clinical Microbiology Apr 2024Whole-genome sequencing (WGS) of microbial pathogens recovered from patients with infectious disease facilitates high-resolution strain characterization and molecular...
Whole-genome sequencing (WGS) of microbial pathogens recovered from patients with infectious disease facilitates high-resolution strain characterization and molecular epidemiology. However, increasing reliance on culture-independent methods to diagnose infectious diseases has resulted in few isolates available for WGS. Here, we report a novel culture-independent approach to genome characterization of , the causative agent of pertussis and a paradigm for insufficient genomic surveillance due to limited culture of clinical isolates. Sequencing libraries constructed directly from residual pertussis-positive diagnostic nasopharyngeal specimens were hybridized with biotinylated RNA "baits" targeting fragments within complex mixtures that contained high concentrations of host and microbial background DNA. Recovery of genome sequence data was evaluated with mock and pooled negative clinical specimens spiked with reducing concentrations of either purified DNA or inactivated cells. Targeted enrichment increased the yield of sequencing reads up to 90% while simultaneously decreasing host reads to less than 10%. Filtered sequencing reads provided sufficient genome coverage to perform characterization via whole-genome single nucleotide polymorphisms and whole-genome multilocus sequencing typing. Moreover, these data were concordant with sequenced isolates recovered from the same specimens such that phylogenetic reconstructions from either consistently clustered the same putatively linked cases. The optimized protocol is suitable for nasopharyngeal specimens with diagnostic IS Ct < 35 and >10 ng DNA. Routine implementation of these methods could strengthen surveillance and study of pertussis resurgence by capturing additional cases with genomic characterization.
Topics: Humans; Bordetella pertussis; Whooping Cough; Phylogeny; Genomics; DNA; Bordetella
PubMed: 38445858
DOI: 10.1128/jcm.01653-23 -
Journal of Preventive Medicine and... Dec 2023The present article offers a historical overview on pertussis (whooping cough) by analysing the ancient epidemic manifestations of the disease and the path towards the...
The present article offers a historical overview on pertussis (whooping cough) by analysing the ancient epidemic manifestations of the disease and the path towards the discovery of an effective vaccine against it. The original mentions of pertussis are examined with reference to Mediaeval Afghanistan and the famous AD 1578 Paris epidemic described by the French physician Guillaume de Baillou. The historical data are then matched with information derived from analyses of phylogenetic trees of B. pertussis. Finally, this article also highlights some recent challenges posed to public health by this infectious disease.
Topics: Humans; Infant; Whooping Cough; Pertussis Vaccine; Phylogeny; Bordetella pertussis; Epidemics; Vaccination
PubMed: 38379743
DOI: 10.15167/2421-4248/jpmh2023.64.4.3163 -
European Archives of... Apr 2024Achromobacter xylosoxidans is an emerging pathogen mainly associated with resistant nosocomial infections. This bacteria had been isolated in the ear together with other...
PURPOSE
Achromobacter xylosoxidans is an emerging pathogen mainly associated with resistant nosocomial infections. This bacteria had been isolated in the ear together with other pathogens in cultures from patients with chronic otitis media, but it had never been reported as a cause of osteomyelitis of the external auditory canal.
CASE PRESENTATION
We present a unique case of a healthy 81-year-old woman who presented with left chronic otorrhea refractory to topical and oral antibiotic treatment. Otomicroscopy revealed an erythematous and exudative external auditory canal (EAC) with scant otorrhea. The tympanic membrane was intact, but an area of bone remodeling with a small cavity anterior and inferior to the bony tympanic frame was observed. Otic culture isolated multi-drug-resistant A. xylosoxidans, only sensitive to meropenem and cotrimoxazole. Temporal bone computed tomography showed an excavation of the floor of the EAC compatible with osteomyelitis. Targeted antibiotherapy for 12 weeks was conducted, with subsequent resolution of symptoms and no progression of the bone erosion.
CONCLUSIONS
Atypical pathogens such as A. xylosoxidans can be the cause of chronic otitis externa. Early diagnosis and specific antibiotherapy can prevent the development of further complications, such as osteomyelitis. In these cases, otic cultures play an essential role to identify the causal germ. This is the first case of EAC osteomyelitis due to A. xylosoxidans reported to date.
Topics: Female; Humans; Aged, 80 and over; Ear Canal; Achromobacter denitrificans; Otitis Externa; Osteomyelitis; Ear Diseases
PubMed: 38367073
DOI: 10.1007/s00405-024-08465-8 -
PloS One 2024The emergence of macrolide-resistant Bordetella pertussis (MRBP) is a significant problem because it reduces treatment options for pertussis and exacerbates the severity...
The emergence of macrolide-resistant Bordetella pertussis (MRBP) is a significant problem because it reduces treatment options for pertussis and exacerbates the severity and spread of the disease. MRBP has been widely prevalent in mainland China since the 2010s and has been sporadically detected in other Asian countries. In Japan, two MRBP clinical strains were first isolated in Tokyo and Osaka between June and July 2018. The isolates BP616 in Osaka and BP625 in Tokyo harbored the same virulence-associated allelic genes (including ptxP1, ptxA1, prn1, fim3A, and fhaB3) and MT195 genotype and exhibited similar antimicrobial susceptibility profiles. However, despite their simultaneous occurrence, a distinguishable epidemiological link between these isolates could not be established. To gain further insight into the genetic relationship between these isolates in this study, we performed whole-genome analyses. Phylogenetic analysis based on genome-wide single-nucleotide polymorphisms revealed that the isolates belonged to one of the three clades of Chinese MRBP isolates, but there were 11 single-nucleotide polymorphism differences between BP616 and BP625. Genome structure analysis revealed two large inversions (202 and 523 kbp) and one small transposition (3.8 kbp) between the genomes. These findings indicate that the two Japanese MRBP isolates are closely related to Chinese MRBP isolates but are genomically distinct, suggesting that they were introduced into Japan from mainland China through different transmission routes.
Topics: Humans; Bordetella pertussis; Macrolides; Japan; Phylogeny; Whooping Cough; Anti-Bacterial Agents; Genotype
PubMed: 38359004
DOI: 10.1371/journal.pone.0298147 -
Heliyon Feb 2024Autoimmune thyroiditis (AIT), also known as Hashimoto's thyroiditis (HT) or chronic lymphocytic thyroiditis, is a prevalent autoimmune disorder. Despite its high...
BACKGROUND
Autoimmune thyroiditis (AIT), also known as Hashimoto's thyroiditis (HT) or chronic lymphocytic thyroiditis, is a prevalent autoimmune disorder. Despite its high prevalence, the pathogenesis of AIT remains unclear. Previous studies have suggested a potential association between gut microbiota and AIT. However, whether this relationship is causal or coincidental remains uncertain. To address this gap in knowledge, our study aimed to investigate the potential causal association between gut microbiota and AIT using the two-sample Mendelian randomization (MR) method.
METHODS
Summary-level gut microbiota data comprising 211 taxa (131 genera, 35 families, 20 orders, 16 classes, and 9 phyla) were obtained from the comprehensive MiBioGen study. Genetic associations with 22 gastrointestinal diseases were extracted from the UK Biobank, FinnGen study, and various extensive GWAS studies. A meticulous MR analysis was conducted to evaluate the causal relationship between genetically predicted gut microbiota and these gastrointestinal diseases. Sensitivity analyses and tests for heterogeneity were systematically performed to validate the reliability of our findings.
RESULTS
Six gut microbiota species showed significant associations with AIT according to the IVW method. Among them, the following exhibited negative associations with AIT: family Alcaligenaceae, family Pasteurellaceae (ID: 3689), family Peptococcaceae, genus Lachnospira, genus Victivallis, and order Pasteurellales (ID: 3688). No evidence of pleiotropy or heterogeneity was detected.
CONCLUSION
The MR analysis uncovered a causal relationship at the genetic prediction level between specific gut microbiota and AIT. These findings offer novel insights into the mechanisms governing the development of AIT mediated by gut microbiota. This knowledge could inform the design of future interventions, potentially involving microbiome-related strategies, to address the mechanisms associated with AIT development.
PubMed: 38356548
DOI: 10.1016/j.heliyon.2024.e25652