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BMC Genomics May 2007Bordetella pertussis, the causative agent of whooping cough, is a highly clonal pathogen of the respiratory tract. Its lack of genetic diversity, relative to many...
BACKGROUND
Bordetella pertussis, the causative agent of whooping cough, is a highly clonal pathogen of the respiratory tract. Its lack of genetic diversity, relative to many bacterial pathogens, could limit its ability to adapt to a hostile and changing host environment. This limitation might be overcome by phase variation, as observed for other mucosal pathogens. One of the most common mechanisms of phase variation is reversible expansion or contraction of homopolymeric tracts (HPTs).
RESULTS
The genomes of B. pertussis and the two closely related species, B. bronchiseptica and B. parapertussis, were screened for homopolymeric tracts longer than expected on the basis of chance, given their nucleotide compositions. Sixty-nine such HPTs were found in total among the three genomes, 74% of which were polymorphic among the three species. Nine HPTs were genotyped in a collection of 90 geographically and temporally diverse B. pertussis strains using the polymerase chain reaction/ligase detection reaction (PCR/LDR) assay. Six HPTs were polymorphic in this collection of B. pertussis strains. Of note, one of these polymorphic HPTs was found in the fimX promoter, where a single base insertion variant was present in seven strains, all of which were isolated prior to introduction of the pertussis vaccine. Transcript abundance of fimX was found to be 3.8-fold lower in strains carrying the longer allele. HPTs in three other genes, tcfA, bapC, and BP3651, varied widely in composition across the strain collection and displayed allelic polymorphism within single cultures.
CONCLUSION
Allelic polymorphism at homopolymeric tracts is common within the B. pertussis genome. Phase variability may be an important mechanism in B. pertussis for evasion of the immune system and adaptation to different niches in the human host. High sensitivity and specificity make the PCR/LDR assay a powerful tool for investigating allelic variation at HPTs. Using this method, allelic diversity and phase variation were demonstrated at several B. pertussis loci.
Topics: Alleles; Bacterial Proteins; Bordetella bronchiseptica; Bordetella parapertussis; Bordetella pertussis; DNA, Bacterial; Evolution, Molecular; Fimbriae Proteins; Genome, Bacterial; Humans; Polymerase Chain Reaction; Polymorphism, Genetic; Promoter Regions, Genetic; Repetitive Sequences, Nucleic Acid
PubMed: 17509142
DOI: 10.1186/1471-2164-8-122 -
CMAJ : Canadian Medical Association... Jul 2005There has been much recent concern over an increasing incidence of pertussis despite high levels of vaccine coverage of infants. Many reports have documented that much... (Review)
Review
There has been much recent concern over an increasing incidence of pertussis despite high levels of vaccine coverage of infants. Many reports have documented that much of the increased incidence is due to infection in adolescents and adults. This renewal of interest in pertussis comes at a time when the findings of the Bordetella genome project have led to a quantum leap forward in our understanding of the biology, evolution and pathogenesis of the bacterium responsible for the disease. The impact of this basic research on current clinical problems posed by B. pertussis infection is discussed.
Topics: Adaptation, Physiological; Adolescent; Adult; Age Factors; Aged; Antigenic Variation; Bordetella pertussis; Child; DNA, Bacterial; Female; Humans; Immunity; Incidence; Male; Middle Aged; Pertussis Vaccine; Whooping Cough
PubMed: 15997046
DOI: 10.1503/cmaj.050105 -
Journal of Applied Microbiology Jun 2012To characterize Bordetella pertussis vaccine strains in comparison with current circulating bacteria.
AIM
To characterize Bordetella pertussis vaccine strains in comparison with current circulating bacteria.
METHODS AND RESULTS
Genomic and proteomic analyses of Bp137 were performed in comparison with other vaccine strains used in Latin America (Bp509 and Bp10536) and with the clinical Argentinean isolate Bp106. Tohama I strain was used as reference strain. Pulse-field gel electrophoresis (PFGE) and pertussis toxin promoter (ptxP) sequence analysis revealed that Bp137 groups with Bp509 in PFGE group III and contains ptxP2 sequence. Tohama I (group II) and Bp10536 (group I) contain ptxP1 sequence, while Bp106 belongs to a different PFGE cluster and contains ptxP3. Surface protein profiles diverged in at least 24 peptide subunits among the studied strains. From these 24 differential proteins, Bp10536 shared the expression of ten proteins with Tohama I and Bp509, but only three with Bp137. In contrast, seven proteins were detected exclusively in Bp137 and Bp106.
CONCLUSIONS
Bp137 showed more features in common with the clinical isolate Bp106 than the other vaccine strains here included.
SIGNIFICANCE AND IMPACT OF THE STUDY
The results presented show that the old strains included in vaccines are not all equal among them. These findings together with the data of circulating bacteria should be taken into account to select the best vaccine to be included in a national immunization programme.
Topics: Bordetella pertussis; Genotype; Humans; Immunization Programs; Latin America; Pertussis Vaccine; Phenotype; Proteomics
PubMed: 22471652
DOI: 10.1111/j.1365-2672.2012.05299.x -
Infection and Immunity Nov 1992Recent reports have demonstrated that Bordetella pertussis has invasive behavior in vivo and in vitro. In this study, we investigated the ability of a virulent strain,...
Recent reports have demonstrated that Bordetella pertussis has invasive behavior in vivo and in vitro. In this study, we investigated the ability of a virulent strain, avirulent mutants, and mutants deficient in specific virulence factors to enter and survive intracellularly in human macrophages in vitro. Uptake of virulent B. pertussis was dose dependent and occurred in the absence of serum or specific antibody, with entry occurring via a microfilament-dependent phagocytic process. The virulent wild-type parental strain was internalized and persisted intracellularly over the 3 days of experiments, as determined by transmission electron microscopy and by recovery of viable plate counts. This is the first report of long-term survival of B. pertussis in human macrophages. Avirulent mutants entered macrophages, but at only an average of 1.5% of virulent parental levels, and did not survive intracellularly. Mutants which did not express adenylate cyclase toxin, filamentous hemagglutinin, or pertussis toxin had decreased abilities to enter and to survive inside macrophages. The results suggest that the internalization process, as well as intracellular survival, is virulence dependent and that mutations which inactivate expression of virulence factors may affect both. The ability of B. pertussis to enter and persist inside macrophages may be important not only for survival of the bacteria but also in the pathogenesis of whooping cough.
Topics: Bordetella pertussis; Cadaverine; Cytochalasin D; Humans; Macrophages; Microscopy, Electron; Phagocytosis; Time Factors
PubMed: 1398970
DOI: 10.1128/iai.60.11.4578-4585.1992 -
The Journal of International Medical... 2006We evaluated the diagnostic performance of a genomic DNA amplification method for Bordetella pertussis and Bordetella parapertussis compared with culture isolation.... (Comparative Study)
Comparative Study
We evaluated the diagnostic performance of a genomic DNA amplification method for Bordetella pertussis and Bordetella parapertussis compared with culture isolation. Aliquots from B. pertussis and B. parapertussis cultures were added to sterile physiological saline or sterile distilled water to give bacterial suspensions of 10(8) cells/ml and serial dilutions were prepared. Suspensions in physiological saline were cultured on charcoal agar medium; bacterial growth was observed up to dilutions of 10(-7). Suspensions in distilled water were subjected to DNA extraction and nested polymerase chain reaction (PCR) was performed on the extracts; the PCR was positive up to dilutions of 10(-8) for B. pertussis and 10(-9) for B. parapertussis. Since the efficacy of culture isolation, regarded as the standard for the detection of B. pertussis and B. parapertussis, declines after the first stage of pertussis or with prior vaccination or antibiotic therapy, PCR, although not yet standardized, may provide an alternative diagnostic tool.
Topics: Bacterial Typing Techniques; Bordetella Infections; Bordetella parapertussis; Bordetella pertussis; Culture Techniques; DNA, Bacterial; Diagnostic Techniques and Procedures; Humans; Polymerase Chain Reaction
PubMed: 16989492
DOI: 10.1177/147323000603400405 -
Microbial Genomics Nov 2018The genome of Bordetella pertussis is complex, with high G+C content and many repeats, each longer than 1000 bp. Long-read sequencing offers the opportunity to produce...
The genome of Bordetella pertussis is complex, with high G+C content and many repeats, each longer than 1000 bp. Long-read sequencing offers the opportunity to produce single-contig B. pertussis assemblies using sequencing reads which are longer than the repetitive sections, with the potential to reveal genomic features which were previously unobservable in multi-contig assemblies produced by short-read sequencing alone. We used an R9.4 MinION flow cell and barcoding to sequence five B. pertussis strains in a single sequencing run. We then trialled combinations of the many nanopore user community-built long-read analysis tools to establish the current optimal assembly pipeline for B. pertussis genome sequences. This pipeline produced closed genome sequences for four strains, allowing visualization of inter-strain genomic rearrangement. Read mapping to the Tohama I reference genome suggests that the remaining strain contains an ultra-long duplicated region (almost 200 kbp), which was not resolved by our pipeline; further investigation also revealed that a second strain that was seemingly resolved by our pipeline may contain an even longer duplication, albeit in a small subset of cells. We have therefore demonstrated the ability to resolve the structure of several B. pertussis strains per single barcoded nanopore flow cell, but the genomes with highest complexity (e.g. very large duplicated regions) remain only partially resolved using the standard library preparation and will require an alternative library preparation method. For full strain characterization, we recommend hybrid assembly of long and short reads together; for comparison of genome arrangement, assembly using long reads alone is sufficient.
Topics: Bordetella pertussis; Genome, Bacterial; Molecular Sequence Annotation; Nanopores; Sequence Analysis, DNA
PubMed: 30461375
DOI: 10.1099/mgen.0.000234 -
MBio Aug 2022Copper is essential to most living beings but also highly toxic and as such is an important player at the host-pathogen interface. Bacteria have thus developed...
Copper is essential to most living beings but also highly toxic and as such is an important player at the host-pathogen interface. Bacteria have thus developed homeostatic mechanisms to tightly control its intracellular concentration. Known Cu export and import systems are under transcriptional control, whereas posttranscriptional regulatory mechanisms are yet to be characterized. We identified a three-gene operon, , downregulated by copper and notably encoding a TonB-dependent transporter in Bordetella pertussis. We show here that the protein encoded by the first gene, which is a member of the DUF2946 protein family, represents a new type of upstream Open Reading Frame (uORF) involved in posttranscriptional regulation of the downstream genes. In the absence of copper, the entire operon is transcribed and translated. Perception of copper by the nascent -coded protein via its conserved CXXC motif triggers Rho-dependent transcription termination between the first and second genes by relieving translation arrest on a conserved C-terminal RAPP motif. Homologs of are widespread in bacterial genomes, where they head operons predicted to participate in copper homeostasis. This work has thus unveiled a new mode of genetic regulation by a transition metal and identified a regulatory function for a member of an uncharacterized family of bacterial proteins that we have named CruR, for copper-responsive upstream regulator. Copper is a transition metal necessary for living beings but also extremely toxic. Bacteria thus tightly control its homeostasis with transcriptional regulators. In this work, we have identified in the whooping cough agent Bordetella pertussis a new control mechanism mediated by a small protein called CruR, for copper-responsive upstream regulator. While being translated by the ribosome CruR is able to perceive intracellular copper, which shuts down the transcription of downstream genes of the same operon, coding for a copper uptake system. This mechanism limits the import of copper in conditions where it is abundant for the bacterium. This is the first report of "posttranscriptional regulation" in response to copper. Homologs of CruR genes head many operons harboring copper-related genes in various bacteria, and therefore the regulatory function unveiled here is likely a general property of this new protein family.
Topics: Bacterial Proteins; Bordetella pertussis; Copper; Gene Expression Regulation; Gene Expression Regulation, Bacterial; Open Reading Frames; Operon; Ribosomes
PubMed: 35862763
DOI: 10.1128/mbio.00912-22 -
Infection and Immunity Oct 1987Pertussis toxin is one of the major virulence determinants produced by Bordetella pertussis. The DNA encoding the structural genes for pertussis toxin was cloned in...
Pertussis toxin is one of the major virulence determinants produced by Bordetella pertussis. The DNA encoding the structural genes for pertussis toxin was cloned in Escherichia coli, and pertussis toxin subunit S4 was expressed under the control of the tac promoter. Mutations were introduced into the cloned toxin genes, and a conjugative shuttle vector system was devised for delivering the mutations from E. coli back into B. pertussis. The mutations were introduced by allelic exchange into the chromosome of B. pertussis resulting in a series of B. pertussis strains which were isogenic except at the loci encoding the structural genes for pertussis toxin. These B. pertussis strains were utilized to study the biogenesis of pertussis toxin. Polar mutations in the S1 gene led to a lack of detectable S2 or S4 subunits in whole-cell lysates, suggesting a polycistronic arrangement for these genes. Mutations in the S5 subunit gene resulted in a truncated S1 subunit, while mutations in the S4 gene resulted in a lack of detectable S2 subunit, suggesting that physical relationships among the toxin subunits are directly reflected in the stable biogenesis of the subunits.
Topics: Alleles; Bordetella pertussis; Chromosome Mapping; Chromosomes, Bacterial; Cloning, Molecular; DNA, Bacterial; Gene Expression Regulation; Genes, Bacterial; Genetic Vectors; Immunoassay; Mutation; Nucleic Acid Hybridization; Operon; Pertussis Toxin; Plasmids; Promoter Regions, Genetic; Virulence; Virulence Factors, Bordetella
PubMed: 2888733
DOI: 10.1128/iai.55.10.2465-2470.1987 -
Journal of Microbiology, Immunology,... Aug 2021Pertussis is an important cause of hospitalization in children. Limited data on pertussis have been reported from China. The aim of this study was to characterize...
BACKGROUND
Pertussis is an important cause of hospitalization in children. Limited data on pertussis have been reported from China. The aim of this study was to characterize clinically suspected pertussis attributable to Bordetella pertussis among children and determine factors associated with longer duration of hospital stay in B. pertussis infection.
METHODS
Two hundred and seventeen consecutive children with clinically suspected pertussis were prospectively enrolled in the study between Jan 2016 through Aug 2017. Variables assessed included demographics, clinical symptoms and laboratory findings. Cox proportional hazards regression model were used to predict variables associated with longer duration of hospital stay.
RESULTS
Among the 217 patients with clinically suspected pertussis, B. pertussis was found in 106 (48.8%) patients. Of the 106 children with B. pertussis infection, 63 (59.4%) patients had coinfections with majority due to rhinovirus (HRV) (30.2%), Mycoplasma pneumoniae (29.2%) and human bocavirus (hBoV) (11.3%). Presence of coinfection [odds ratio (OR): 1.73, CI: 1.17-2.54], age ≤ 3 months (OR: 1.51, CI: 1.09 to 2.27), and WBC count ≥30 × 10/L (OR: 1.66, CI: 1.07 to 2.84) were independently associated with a longer hospital stay.
CONCLUSIONS
B. pertussis infection had a high coinfection rate with the majority of coinfections due to HRV, M. pneumoniae and hBoV. Presence of coinfection, Age ≤3 months and WBC count ≥30 × 10/L were associated with a longer hospital stay. Children admitted with pertussis need close monitoring when they had evidence of coinfection, Age ≤3 months, WBC count ≥30 × 10/L.
Topics: Bordetella pertussis; Child; Child, Preschool; China; Coinfection; Female; Humans; Infant; Length of Stay; Male; Mycoplasma pneumoniae; Prevalence; Proportional Hazards Models; Prospective Studies; Viruses; Whooping Cough
PubMed: 32245724
DOI: 10.1016/j.jmii.2020.03.006 -
Emerging Infectious Diseases Aug 2009Before childhood vaccination was introduced in the 1940s, pertussis was a major cause of infant death worldwide. Widespread vaccination of children succeeded in reducing...
Before childhood vaccination was introduced in the 1940s, pertussis was a major cause of infant death worldwide. Widespread vaccination of children succeeded in reducing illness and death. In the 1990s, a resurgence of pertussis was observed in a number of countries with highly vaccinated populations, and pertussis has become the most prevalent vaccine-preventable disease in industrialized countries. We present evidence that in the Netherlands the dramatic increase in pertussis is temporally associated with the emergence of Bordetella pertussis strains carrying a novel allele for the pertussis toxin promoter, which confers increased pertussis toxin (Ptx) production. Epidemiologic data suggest that these strains are more virulent in humans. We discuss changes in the ecology of B. pertussis that may have driven this adaptation. Our results underline the importance of Ptx in transmission, suggest that vaccination may select for increased virulence, and indicate ways to control pertussis more effectively.
Topics: Adolescent; Alleles; Bacterial Outer Membrane Proteins; Base Sequence; Bordetella pertussis; Child; Child, Preschool; Communicable Diseases, Emerging; DNA Primers; DNA, Bacterial; Genes, Bacterial; Humans; Infant; Molecular Epidemiology; Molecular Sequence Data; Netherlands; Pertussis Toxin; Polymorphism, Genetic; Promoter Regions, Genetic; Sequence Homology, Nucleic Acid; Virulence; Virulence Factors, Bordetella; Whooping Cough; Young Adult
PubMed: 19751581
DOI: 10.3201/eid1508.081511