-
MBio Oct 2017Nearly all virulence factors in are activated by a master two-component system, BvgAS, composed of the sensor kinase BvgS and the response regulator BvgA. When BvgS is...
Nearly all virulence factors in are activated by a master two-component system, BvgAS, composed of the sensor kinase BvgS and the response regulator BvgA. When BvgS is active, BvgA is phosphorylated (BvgA~P), and virulence-activated genes (s) are expressed [Bvg(+) mode]. When BvgS is inactive and BvgA is not phosphorylated, virulence-repressed genes (s) are induced [Bvg(-) mode]. Here, we have used transcriptome sequencing (RNA-seq) and reverse transcription-quantitative PCR (RT-qPCR) to define the BvgAS-dependent regulon of Tohama I. Our analyses reveal more than 550 BvgA-regulated genes, of which 353 are newly identified. BvgA-activated genes include those encoding two-component systems (such as ), multiple other transcriptional regulators, and the extracytoplasmic function (ECF) sigma factor , which is needed for type 3 secretion system (T3SS) expression, further establishing the importance of BvgA~P as an apex regulator of transcriptional networks promoting virulence. Using transcription, we demonstrate that the promoter for is directly activated by BvgA~P. BvgA-FeBABE cleavage reactions identify BvgA~P binding sites centered at positions -41.5 and -63.5 in Most importantly, we show for the first time that genes for multiple and varied metabolic pathways are significantly upregulated in the Bvg(-) mode. These include genes for fatty acid and lipid metabolism, sugar and amino acid transporters, pyruvate dehydrogenase, phenylacetic acid degradation, and the glycolate/glyoxylate utilization pathway. Our results suggest that metabolic changes in the Bvg(-) mode may be participating in bacterial survival, transmission, and/or persistence and identify over 200 new s that can be tested for function. Within the past 20 years, outbreaks of whooping cough, caused by , have led to respiratory disease and infant mortalities, despite good vaccination coverage. This is due, at least in part, to the introduction of a less effective acellular vaccine in the 1990s. It is crucial, then, to understand the molecular basis of growth and infection. The two-component system BvgA (response regulator)/BvgS (histidine kinase) is the master regulator of virulence genes. We report here the first RNA-seq analysis of the BvgAS regulon in , revealing that more than 550 genes are regulated by BvgAS. We show that genes for multiple and varied metabolic pathways are highly regulated in the Bvg(-) mode (absence of BvgA phosphorylation). Our results suggest that metabolic changes in the Bvg(-) mode may be participating in bacterial survival, transmission, and/or persistence.
Topics: Bacterial Proteins; Bordetella pertussis; Gene Expression Regulation, Bacterial; Genes, Regulator; High-Throughput Nucleotide Sequencing; Promoter Regions, Genetic; Regulon; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Transcription Factors; Transcriptome; Virulence
PubMed: 29018122
DOI: 10.1128/mBio.01526-17 -
Microbes and Infection 2019The introduction of pertussis vaccination in the 1950s resulted in a significant decrease in the incidence of disease. However, since the 1990s many highly vaccinated...
The introduction of pertussis vaccination in the 1950s resulted in a significant decrease in the incidence of disease. However, since the 1990s many highly vaccinated countries have observed the re-emergence of the disease. One of the causes of this phenomenon might be related to the adaptation of Bordetella pertussis to vaccination. The purpose of the presented study was an investigation of the emergence and spread of vaccine antigen-deficient B. pertussis isolates in Poland and genomic characterization of the currently circulating pathogen population using PFGE, MLVA and MAST. The results revealed that all tested isolates expressed Ptx, FHA and ACT antigens but 15.4% (4/26) of isolates from 2010 to 2016 were Prn-deficient. Moreover, one TcfA-deficient isolate was collected in 2015. The genotyping showed a genetic distinction between the isolates circulating in 2010-2016 and isolates from previous periods. The majority of currently circulating isolates belonged to PFGE group IV (96.2%), type MT27 (73.1%), and carried ptxA1-ptxC2-ptxP3-prn2-tcfA2-fim2-1-fim3-1 alleles (61.5%). The unique genetic structure of the B. pertussis population in Poland has changed since 2010 and became similar to that observed in countries with aP vaccination. This could be a result of increasing use of aP vaccines (60% of primary vaccination in 2013) over wP vaccines, which have been broadly used for primary vaccination in Poland for decades.
Topics: Antigens, Bacterial; Bacterial Outer Membrane Proteins; Bordetella pertussis; DNA, Bacterial; Genetic Variation; Genome, Bacterial; Genotype; Humans; Pertussis Vaccine; Poland; Time Factors; Vaccination; Virulence Factors, Bordetella; Whooping Cough
PubMed: 30580013
DOI: 10.1016/j.micinf.2018.12.001 -
Theoretical Population Biology Aug 2015Pertussis, or whooping cough, is an important respiratory infection causing considerable infant mortality worldwide. Recently, incidence has risen in countries with...
Pertussis, or whooping cough, is an important respiratory infection causing considerable infant mortality worldwide. Recently, incidence has risen in countries with strong vaccine programmes and there are concerns about antigenic shift resulting in vaccine evasion. Interactions between pertussis and non-vaccine-preventable strains will play an important role in the evolution and population dynamics of pertussis. In particular, if we are to understand the role strain replacement plays in vaccinated settings, it will be essential to understand how strains or variants of pertussis interact. Here we explore under what conditions we would expect strain replacement to be of concern in pertussis. We develop a dynamic transmission model that allows for coinfection between Bordetella pertussis (the main causative agent of pertussis) and a strain or variant unaffected by the vaccine. We incorporate both neutrality (in the sense of ecological/population genetic neutrality) and immunity into the model, leaving the specificity of the immune response flexible. We find that strain replacement may be considerable when immunity is non-specific. This is in contrast to previous findings where neutrality was not considered. We conclude that the extent to which models reflect ecological neutrality can have a large impact on conclusions regarding strain replacement. This will likely have onward consequences for estimates of vaccine efficacy and cost-effectiveness.
Topics: Bordetella pertussis; Models, Biological
PubMed: 26032910
DOI: 10.1016/j.tpb.2015.05.003 -
Clinical Microbiology and Infection :... May 2024In Finland, whole cell pertussis vaccine (wP) was introduced in 1952 and was replaced by acellular pertussis vaccine (aP) without fimbrial (FIM) antigen in 2005. We...
OBJECTIVES
In Finland, whole cell pertussis vaccine (wP) was introduced in 1952 and was replaced by acellular pertussis vaccine (aP) without fimbrial (FIM) antigen in 2005. We aimed to analyse the changes in serotypes of circulating Bordetella pertussis before and after acellular vaccination and to explore the relationship between biofilm formation and serotype diversity after the introduction of aP vaccine.
METHODS
Serotyping of 1399 B. pertussis isolates collected at the Finnish National Reference Laboratory for Pertussis and Diphtheria in Turku, Finland, from 1974 to 2023 was performed by slide agglutination or indirect ELISA. Of 278 isolates collected after 2005, 53 were selected, genotyped for fim3 and fim2 alleles, and tested for biofilm formation. The selection criteria included maintaining a relatively equal distribution of isolates per time interval, ensuring approximately a 50:50 ratio of FIM2 (N = 26) and FIM3 (N = 27) serotypes. The reference strain Tohama I was used as a control.
RESULTS
During the wP era, the majority of circulating B. pertussis exhibited the FIM2 serotype. However, FIM3 strains have appeared since 1999 and become prevalent. After the implementation of aP vaccines, the distribution of serotypes has exhibited substantial variability. FIM3 isolates displayed an enhanced biofilm formation compared to FIM2 isolates (Geometric mean value (95% CI): 0.90 (0.79-1.03) vs. 0.75 (0.65-0.85); p < 0.05). Of the 27 FIM3 isolates, 8 harboured fim3-1 and 19 fim3-2 alleles. FIM3 isolates with fim3-2 allele were significantly associated with increased biofilm formation when compared to those with fim3-1 (1.07 (0.96-1.19) vs. 0.61 (0.52-0.72); p < 0.0001).
CONCLUSION
Following the implementation of aP vaccines, the distribution of serotypes in Finland has exhibited substantial variability. FIM3 isolates with the fim3-2 allele displayed an enhanced biofilm formation capability compared to FIM2 isolates.
Topics: Biofilms; Finland; Bordetella pertussis; Humans; Whooping Cough; Serogroup; Pertussis Vaccine; Vaccines, Acellular; Fimbriae Proteins; Serotyping; Genotype; Child, Preschool; Child; Infant; Vaccination; Antigens, Bacterial; Virulence Factors, Bordetella
PubMed: 38310999
DOI: 10.1016/j.cmi.2024.01.021 -
Epidemiology and Infection Apr 2014Pertussis or whooping cough has persisted and resurged in the face of vaccination and has become one of the most prevalent vaccine-preventable diseases in Western... (Review)
Review
Pertussis or whooping cough has persisted and resurged in the face of vaccination and has become one of the most prevalent vaccine-preventable diseases in Western countries. The high circulation rate of Bordetella pertussis poses a threat to infants that have not been (completely) vaccinated and for whom pertussis is a severe, life-threatening, disease. The increase in pertussis is mainly found in age groups in which immunity has waned and this has resulted in the perception that waning immunity is the main or exclusive cause for the resurgence of pertussis. However, significant changes in B. pertussis populations have been observed after the introduction of vaccinations, suggesting a role for pathogen adaptation in the persistence and resurgence of pertussis. These changes include antigenic divergence with vaccine strains and increased production of pertussis toxin. Antigenic divergence will affect both memory recall and the efficacy of antibodies, while higher levels of pertussis toxin may increase suppression of the innate and acquired immune system. We propose these adaptations of B. pertussis have decreased the period in which pertussis vaccines are effective and thus enhanced the waning of immunity. We plead for a more integrated approach to the pertussis problem which includes the characteristics of the vaccines, the B. pertussis populations and the interaction between the two.
Topics: Amino Acid Sequence; Bordetella pertussis; Communicable Diseases, Emerging; Epidemics; Humans; Molecular Sequence Data; Mutation; Pertussis Toxin; Pertussis Vaccine; Sequence Alignment; Whooping Cough
PubMed: 23406868
DOI: 10.1017/S0950268813000071 -
FEMS Microbiology Letters Jul 2022Outer-membrane vesicles (OMVs) are promising tools in the development of novel vaccines against the respiratory pathogens Bordetella pertussis and Bordetella...
Outer-membrane vesicles (OMVs) are promising tools in the development of novel vaccines against the respiratory pathogens Bordetella pertussis and Bordetella bronchiseptica. Unfortunately, vesiculation by bordetellae is too low for cost-effective vaccine production. In other bacteria, iron limitation or inactivation of the fur gene has been shown to increase OMV production, presumably by downregulation of the mla genes, which encode machinery for maintenance of lipid asymmetry in the outer membrane. Here, we followed a similar approach in bordetellae. Whereas a fur mutant was readily obtained in B. bronchiseptica, a B. pertussis fur mutant could only be obtained in iron-deplete conditions, indicating that a fur mutation is conditionally lethal in this bacterium. The fur mutants displayed a growth defect in iron-replete media, presumably because constitutive expression of iron-uptake systems resulted in iron intoxication. Accordingly, expression of the Escherichia coli ferritin FtnA to sequester intracellularly accumulated iron rescued the growth of the mutants in these media. The fur mutations led to the constitutive expression of novel vaccine candidates, such as the TonB-dependent receptors FauA for the siderophore alcaligin and BhuR for heme. However, neither inactivation of fur nor growth under iron limitation improved vesiculation, presumably because the expression of the mla genes appeared unaffected.
Topics: Bacterial Proteins; Bordetella bronchiseptica; Bordetella pertussis; Gene Expression Regulation, Bacterial; Iron; Siderophores
PubMed: 35700015
DOI: 10.1093/femsle/fnac047 -
The Journal of Infectious Diseases Mar 2014Before contacting host tissues, invading pathogens directly or indirectly interact with host microbiota, but the effects of such interactions on the initial stages of...
Before contacting host tissues, invading pathogens directly or indirectly interact with host microbiota, but the effects of such interactions on the initial stages of infection are poorly understood. Bordetella pertussis is highly infectious among humans but requires large doses to colonize rodents, unlike a closely related zoonotic pathogen, Bordetella bronchiseptica, raising important questions about the contributions of bacterial competition to initial colonization and host selection. We observed that <100 colony-forming units (CFU) of B. bronchiseptica efficiently infected mice and displaced culturable host microbiota, whereas 10 000 CFU of B. pertussis were required to colonize murine nasal cavities and did not displace host microorganisms. Bacteria isolated from murine nasal cavities but not those from the human lower respiratory tract limited B. pertussis growth in vitro, indicating that interspecies competition may limit B. pertussis colonization of mice. Further, a broad-spectrum antibiotic treatment delivered before B. pertussis inoculation reduced the infectious dose to <100 CFU, and reintroduction of single Staphylococcus or Klebsiella species was sufficient to inhibit B. pertussis colonization of antibiotic-treated mice. Together, these results reveal that resident microorganisms can prevent B. pertussis colonization and influence host specificity, and they provide rationale for manipulating microbiomes to create more-accurate animal models of infectious diseases.
Topics: Animals; Anti-Bacterial Agents; Bordetella Infections; Bordetella bronchiseptica; Bordetella pertussis; Host Specificity; Humans; Klebsiella; Mice, Inbred C57BL; Microbial Interactions; Microbiota; Nasal Cavity; Phylogeny; Sputum; Staphylococcus; Whooping Cough
PubMed: 24227794
DOI: 10.1093/infdis/jit597 -
MBio Apr 2014Bordetella pertussis causes pertussis, a respiratory disease that is most severe for infants. Vaccination was introduced in the 1950s, and in recent years, a resurgence... (Comparative Study)
Comparative Study
Bordetella pertussis causes pertussis, a respiratory disease that is most severe for infants. Vaccination was introduced in the 1950s, and in recent years, a resurgence of disease was observed worldwide, with significant mortality in infants. Possible causes for this include the switch from whole-cell vaccines (WCVs) to less effective acellular vaccines (ACVs), waning immunity, and pathogen adaptation. Pathogen adaptation is suggested by antigenic divergence between vaccine strains and circulating strains and by the emergence of strains with increased pertussis toxin production. We applied comparative genomics to a worldwide collection of 343 B. pertussis strains isolated between 1920 and 2010. The global phylogeny showed two deep branches; the largest of these contained 98% of all strains, and its expansion correlated temporally with the first descriptions of pertussis outbreaks in Europe in the 16th century. We found little evidence of recent geographical clustering of the strains within this lineage, suggesting rapid strain flow between countries. We observed that changes in genes encoding proteins implicated in protective immunity that are included in ACVs occurred after the introduction of WCVs but before the switch to ACVs. Furthermore, our analyses consistently suggested that virulence-associated genes and genes coding for surface-exposed proteins were involved in adaptation. However, many of the putative adaptive loci identified have a physiological role, and further studies of these loci may reveal less obvious ways in which B. pertussis and the host interact. This work provides insight into ways in which pathogens may adapt to vaccination and suggests ways to improve pertussis vaccines. IMPORTANCE Whooping cough is mainly caused by Bordetella pertussis, and current vaccines are targeted against this organism. Recently, there have been increasing outbreaks of whooping cough, even where vaccine coverage is high. Analysis of the genomes of 343 B. pertussis isolates from around the world over the last 100 years suggests that the organism has emerged within the last 500 years, consistent with historical records. We show that global transmission of new strains is very rapid and that the worldwide population of B. pertussis is evolving in response to vaccine introduction, potentially enabling vaccine escape.
Topics: Adaptation, Biological; Bordetella pertussis; Cluster Analysis; Communicable Diseases, Emerging; Evolution, Molecular; Genome, Bacterial; Global Health; Humans; Infant; Pertussis Vaccine; Phylogeny; Vaccination; Whooping Cough
PubMed: 24757216
DOI: 10.1128/mBio.01074-14 -
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 -
MBio Oct 2021The ability of bacterial pathogens to acquire essential micronutrients is critical for their survival in the host environment. Manganese plays a complex role in the...
The ability of bacterial pathogens to acquire essential micronutrients is critical for their survival in the host environment. Manganese plays a complex role in the virulence of a variety of pathogens due to its function as an antioxidant and enzymatic cofactor. Therefore, host cells deprive pathogens of manganese to prevent or attenuate infection. Here, we show that evolution of the human-restricted pathogen Bordetella pertussis has selected for an inhibitory duplication within a manganese exporter of the calcium:cation antiporter superfamily. Intriguingly, upon exposure to toxic levels of manganese, the nonfunctional exporter becomes operative in resister cells due to a unique reverse adaptation mechanism. However, compared with wild-type (wt) cells, the resisters carrying a functional copy of the exporter displayed strongly reduced intracellular levels of manganese and impaired growth under oxidative stress. Apparently, inactivation of the manganese exporter and the resulting accumulation of manganese in the cytosol benefited the pathogen by improving its survival under stress conditions. The inhibitory duplication within the exporter gene is highly conserved among B. pertussis strains, absent from all other species and from a vast majority of organisms across all kingdoms of life. Therefore, we conclude that inactivation of the exporter gene represents an exceptional example of a flexible genome decay strategy employed by a human pathogen to adapt to its exclusive host. Bordetella pertussis, a respiratory pathogen restricted to humans, continuously adapts its genome to its exclusive host. We show that speciation of this reemerging pathogen was accompanied by loss of function of the manganese exporter. Intriguingly, the functionality of the exporter can be restored in the presence of toxic levels of manganese by a unique genetic modification. However, compared with the wt strain, the strain carrying the functional exporter failed to resist the oxidative stress . Thus, our data demonstrate that inactivation of the exporter resulting in manganese accumulation assists B. pertussis in adaptation to oxidative stress. We conclude that this sophisticated process of reverse adaptation enables B. pertussis to adjust to rapidly changing environments by facilitating its resistance to both manganese toxicity and manganese scarcity.
Topics: Bacterial Proteins; Bordetella pertussis; Gene Expression Regulation, Bacterial; Humans; Manganese; Oxidative Stress; Virulence; Virulence Factors; Whooping Cough
PubMed: 34700381
DOI: 10.1128/mBio.01902-21