Effect of carbohydrates on the adhesion of Bordetella bronchiseptica to the respiratory epithelium in rabbits

This study proposes an ecological approach for preventing respiratory tract infections caused by Bordetella bronchiseptica in mammals using a mixture of carbohydrates. In an in vivo study, 51-day-old New Zealand rabbits were treated with a solution containing 1 × 107 CFUs of B. bronchiseptica and 250 μg of one of the following carbohydrates: N acetylglucosamine (GlcNAc), N acetylgalactosamine (GalNAc), alpha methyl mannose (AmeMan), alpha methyl glucose (AmeGlc) and sialic acid (Neu5AC). Positive (B. bronchiseptica) and negative (Physiological Saline Solution (PSS)) controls were included. Animals treated with GlcNAc or AmeGlc showed no clinical signs of infection and exhibited a significant reduction (p < 0.05) in the severity of microscopic lesions evaluated in the nasal cavity and lung compared with the positive controls. Additionally, the presence of bacteria was not detected through microbiological isolation or PCR in the lungs of animals treated with these sugars. Use of a mixture of GlcNAc and AmeGlc resulted in greater inhibition of microscopic lesions, with a significant reduction (p < 0.05) in the severity of these lesions compared to the results obtained using individual sugars. Furthermore, the bacterium was not detected through microbiological isolation, Polymerase Chain Reaction (PCR) or indirect immunoperoxidase (IIP) in this group.

Bordetella bronchiseptica and Bordetella pertussis: Similarities and Differences in Infection, Immuno-Modulation, and Vaccine Considerations

Bordetella pertussis and Bordetella bronchiseptica belong to the genus Bordetella, which comprises 14 other species. B. pertussis is responsible for whooping cough in humans, a severe infection in children and less severe or chronic in adults. These infections are restricted to humans and currently increasing worldwide. B. bronchiseptica is involved in diverse respiratory infections in a wide range of mammals. For instance, the canine infectious respiratory disease complex (CIRDC), characterized by a chronic cough in dogs. At the same time, it is increasingly implicated in human infections, while remaining an important pathogen in the veterinary field. Both Bordetella can evade and modulate host immune responses to support their persistence, although it is more pronounced in B. bronchiseptica infection. The protective immune responses elicited by both pathogens are comparable, while there are important characteristics in the mechanisms that differ. However, B. pertussis pathogenesis is more difficult to decipher in animal models than those of B. bronchiseptica because of its restriction to humans. Nevertheless, the licensed vaccines for each Bordetella are different in terms of formulation, route of administration and immune responses induced, with no known cross-reaction between them. Moreover, the target of the mucosal tissues and the induction of long-lasting cellular and humoral responses are required to control and eliminate Bordetella. In addition, the interaction between both veterinary and human fields are essential for the control of this genus, by preventing the infections in animals and the subsequent zoonotic transmission to humans.

Bordetella spp. utilize the type 3 secretion system to manipulate the VIP/VPAC2 signaling and promote colonization and persistence of the three classical Bordetella in the lower respiratory tract

Introduction

Bordetella are respiratory pathogens comprised of three classical Bordetella species: B. pertussis, B. parapertussis, and B. bronchiseptica. With recent surges in Bordetella spp. cases and antibiotics becoming less effective to combat infectious diseases, there is an imperative need for novel antimicrobial therapies. Our goal is to investigate the possible targets of host immunomodulatory mechanisms that can be exploited to promote clearance of Bordetella spp. infections. Vasoactive intestinal peptide (VIP) is a neuropeptide that promotes Th2 anti-inflammatory responses through VPAC1 and VPAC2 receptor binding and activation of downstream signaling cascades.

Methods

We used classical growth in vitro assays to evaluate the effects of VIP on Bordetella spp. growth and survival. Using the three classical Bordetella spp. in combination with different mouse strains we were able to evaluate the role of VIP/VPAC2 signaling in the infectious dose 50 and infection dynamics. Finally using the B. bronchiseptica murine model we determine the suitability of VPAC2 antagonists as possible therapy for Bordetella spp. infections.

Results

Under the hypothesis that inhibition of VIP/VPAC2 signaling would promote clearance, we found that VPAC2-/- mice, lacking a functional VIP/VPAC2 axis, hinder the ability of the bacteria to colonize the lungs, resulting in decreased bacterial burden by all three classical Bordetella species. Moreover, treatment with VPAC2 antagonists decrease lung pathology, suggesting its potential use to prevent lung damage and dysfunction caused by infection. Our results indicate that the ability of Bordetella spp. to manipulate VIP/VPAC signaling pathway appears to be mediated by the type 3 secretion system (T3SS), suggesting that this might serve as a therapeutical target for other gram-negative bacteria.

Conclusion

Taken together, our findings uncover a novel mechanism of bacteria-host crosstalk that could provide a target for the future treatment for whooping cough as well as other infectious diseases caused primarily by persistent mucosal infections.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Bordetella bronchiseptica Co-Infection in a Stem Cell Transplant Patient

Bordetella bronchiseptica infections may be overlooked by clinicians due to the uncommon encounter of this pathogen in humans and common isolation of co-pathogens. However, the isolation of B. bronchiseptica in immunocompromised individuals may represent a true infection. We report our experience with the fatal case of a stem cell transplant recipient, co-infected with SARS-CoV-2 and B. bronchiseptica, who was considered fully vaccinated (two doses) at the time of her case in spring 2021. Future studies are needed to evaluate the incidence of bacterial co-infections in immunosuppressed individuals with SARS-CoV-2 and clinicians should remain cognizant of the potential pathogenic role of uncommon pathogens isolated in these individuals.

Comparison of ribotyping and sequence-based typing for discriminating among isolates of Bordetella bronchiseptica

PvuII ribotyping and MLST are each highly discriminatory methods for genotyping Bordetella bronchiseptica, but a direct comparison between these approaches has not been undertaken. The goal of this study was to directly compare the discriminatory power of PvuII ribotyping and MLST, using a single set of geographically and genetically diverse strains, and to determine whether subtyping based on repeat region sequences of the pertactin gene (prn) provides additional resolution. One hundred twenty-two isolates were analyzed, representing 11 mammalian or avian hosts, sourced from the United States, Europe, Israel and Australia. Thirty-two ribotype patterns were identified; one isolate could not be typed. In comparison, all isolates were typeable by MLST and a total of 30 sequence types was identified. An analysis based on Simpson's Index of Diversity (SID) revealed that ribotyping and MLST are nearly equally discriminatory, with SIDs of 0.920 for ribotyping and 0.919 for MLST. Nonetheless, for ten ribotypes and eight MLST sequence types, the alternative method discriminates among isolates that otherwise type identically. Pairing prn repeat region typing with ribotyping yielded 54 genotypes and increased the SID to 0.954. Repeat region typing combined with MLST resulted in 47 genotypes and an SID of 0.944. Given the technical and practical advantages of MLST over ribotyping, and the nominal difference in their SIDs, we conclude MLST is the preferred primary typing tool. We recommend the combination of MLST and prn repeat region typing as a high-resolution, objective and standardized approach valuable for investigating the population structure and epidemiology of B. bronchiseptica.

Novel, host-restricted genotypes of Bordetella bronchiseptica associated with phocine respiratory tract isolates

During a succession of phocine morbillivirus outbreaks spanning the past 25 years, Bordetella bronchiseptica was identified as a frequent secondary invader and cause of death. The goal of this study was to evaluate genetic diversity and the molecular basis for host specificity among seal isolates from these outbreaks. MLST and PvuII ribotyping of 54 isolates from Scottish, English or Danish coasts of the Atlantic or North Sea revealed a single, host-restricted genotype. A single, novel genotype, unique from that of the Atlantic and North Sea isolates, was found in isolates from an outbreak in the Caspian Sea. Phylogenetic analysis based either on MLST sequence, ribotype patterns or genome-wide SNPs consistently placed both seal-specific genotypes within the same major clade but indicates a distinct evolutionary history for each. An additional isolate from the intestinal tract of a seal on the south-west coast of England has a genotype otherwise found in rabbit, guinea pig and pig isolates. To investigate the molecular basis for host specificity, DNA and predicted protein sequences of virulence genes that mediate host interactions were used in comparisons between a North Sea isolate, a Caspian Sea isolate and each of their closest relatives as inferred from genome-wide SNP analysis. Despite their phylogenetic divergence, fewer nucleotide and amino acid substitutions were found in comparisons of the two seal isolates than in comparisons with closely related strains. These data indicate isolates of B. bronchiseptica associated with respiratory disease in seals comprise unique, host-adapted and highly clonal populations.

Microbiological and clinical aspects of respiratory infections associated with Bordetella bronchiseptica

Bordetella bronchiseptica is a well-known veterinary pathogen, but its implication in human disease is probably not fully recognized. The purpose of this study was to determine the clinical significance of 36 B. bronchiseptica isolates from respiratory samples of 22 patients. Therefore, we describe microbiological characteristics, including phenotypic and genotypic identification as well as antimicrobial susceptibilities of the isolates. Clonal relatedness was evaluated using pulsed-field gel electrophoresis (PFGE). Most of the patients had some underlying immunosuppressive condition. Eighteen out of 22 (82%) patients had respiratory symptoms, and the death of 2 patients was associated with respiratory infection.All strains were correctly identified at species level by the simultaneous use of phenotypic methods and were confirmed by specific amplification of the upstream region of the fla gene. Tigecycline, minocycline, doxycycline, colistin, and meropenem were the most active agents tested. PFGE analysis revealed that repeated infections involving each patient had been caused by the same strain.

Bordetella bronchiseptica in the immunosuppressed population - a case series and review

Organisms that are not known to cause serious infection in the immunocompetent population can, in fact, cause devastating illness in immunosuppressed neutropenic populations especially those who are undergoing hematopoietic stem cell transplantation (HSCT), and solid organ transplantation or a history of malignancy. One organism of interest isolated from immunosuppressed patients at our institution was Bordetella bronchiseptica. It is known to cause respiratory tract disease in the animal population which includes dogs, cats, and rabbits. This organism rarely causes serious infection in the immunocompetent population. However; in immunosuppressed patients, it can cause serious pulmonary disease. We present three cases of B. bronchiseptica pneumonia in patients with a history of malignancy.

Transcriptome profiling reveals stage-specific production and requirement of flagella during biofilm development in Bordetella bronchiseptica

We have used microarray analysis to study the transcriptome of the bacterial pathogen Bordetella bronchiseptica over the course of five time points representing distinct stages of biofilm development. The results suggest that B. bronchiseptica undergoes a coordinately regulated gene expression program similar to a bacterial developmental process. Expression and subsequent production of the genes encoding flagella, a classical Bvg⁻ phase phenotype, occurs and is under tight regulatory control during B. bronchiseptica biofilm development. Using mutational analysis, we demonstrate that flagella production at the appropriate stage of biofilm development, i.e. production early subsequently followed by repression, is required for robust biofilm formation and maturation. We also demonstrate that flagella are necessary and enhance the initial cell-surface interactions, thereby providing mechanistic information on the initial stages of biofilm development for B. bronchiseptica. Biofilm formation by B. bronchiseptica involves the production of both Bvg-activated and Bvg-repressed factors followed by the repression of factors that inhibit formation of mature biofilms.

Recurrent respiratory infection caused by Bordetella bronchiseptica in an immunocompetent infant

Bordetella bronchiseptica rarely infects immunocompetent humans. We report an unusual case of recurrent pertussis-like syndrome caused by B. bronchiseptica in a 7-month-old immunocompetent boy. Molecular analysis demonstrated that the isolates from the child and mother were identical.

Dual mechanism of protection by live attenuated Bordetella pertussis BPZE1 against Bordetella bronchiseptica in mice

Bordetella bronchiseptica, a gram-negative bacterium, causes chronic respiratory tract infections in a wide variety of mammalian hosts, including man, and no human vaccine is currently available. Acellular pertussis vaccines protect poorly against B. bronchiseptica, although they contain cross-reactive antigens. We have recently developed Bordetella pertussis BPZE1, a novel, live attenuated pertussis vaccine, currently completing phase I clinical trials in humans, and found that it protects against both B. pertussis and Bordetella parapertussis in mice. Here, we show that a single nasal administration of BPZE1 protects mice against lethal infection with B. bronchiseptica. After challenge, the vaccinated animals displayed markedly reduced lung inflammation and tissue damage, decreased neutrophil infiltration and increased levels of CD4(+)CD25(+)FoxP3(+) regulatory T cells in the lungs compared to non-immunized mice. Depletion of these cells abolished BPZE1-induced protection, indicating that BPZE1 protects against lethal inflammation through the recruitment of regulatory T cells. In addition, the B. bronchiseptica load was significantly decreased in the vaccinated animals. Using passive transfer experiments, protection was found to be essentially cell mediated, and BPZE1-induced Th1 and Th17 T cells recognize whole B. bronchiseptica extracts, although the participation of antibodies in protection cannot be discounted. Thus, a single administration of BPZE1 can confer protection against B. bronchiseptica in mice by a dual mechanism.

Bordetella bronchiseptica in a paediatric cystic fibrosis patient: possible transmission from a household cat

Bordetella bronchiseptica is a zoonotic respiratory pathogen commonly found in domesticated farm and companion animals, including dogs and cats. Here, we report isolation of B. bronchiseptica from a sputum sample of a cystic fibrosis patient recently exposed to a kitten with an acute respiratory illness. Genetic characterization of the isolate and comparison with other isolates of human or feline origin strongly suggest that the kitten was the source of infection.

Bordetella bronchiseptica Pneumonia in an Extremely-Low-Birth-Weight Neonate

Bordetella bronchiseptica, a gram-negative coccobacillus, is a common veterinary pathogen. In both domestic and wild animals, this bacterium causes respiratory infections including infectious tracheobronchitis in dogs and atrophic rhinitis in swine. Human infections are rare and have been documented in immunocompromised hosts. Here, we describe an extremely-low-birth-weight infant with B. bronchiseptica pneumonia. This is the first report that describes the microorganism's responsibility in causing nosocomial infection in a preterm neonate. He recovered uneventfully after a course of meropenem. It is possible that the bacteria colonize the respiratory tracts of our health care workers or parents who may have had contact with pets and then transmitted the bacterium to our patient. Follow-up until 21 months of age showed normal growth and development. He did not suffer from any significant residual respiratory disease.

Structural modifications occurring in lipid A of Bordetella bronchiseptica clinical isolates as demonstrated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Bordetella bronchiseptica is a respiratory pathogen in mammal species and its cell surface lipopolysaccharide-endotoxin is a potent virulence factor. In order to better characterize the endotoxin structure to virulence relationships, we studied the lipid A structures of B. bronchiseptica isolates from human and rabbit origins as a function of their virulence phases. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been widely used for the structural characterization of bacterial endotoxins and their lipid A moieties. This method combined with chemical analytical methods proved to be essential for the characterization of small samples and discrete but essential structural modifications. The occurrence of palmitate (C(16)) in the B. bronchiseptica lipid A structures is shown for the first time at two sites. Their presence was also demonstrated for the first time in correlation with the virulence phase of B. bronchiseptica clinical isolates. The recently identified glucosamine modifications of Bordetella lipids A are also reported in these isolates.

Kitten-transmitted Bordetella bronchiseptica infection in a patient receiving temozolomide for glioblastoma

Bordetella bronchiseptica is a gram negative coccobacillus that can be transmitted from domestic animals and cause severe infections in immunocompromised patients. A 56-year-old man with a left parietal glioblastoma was treated with resection, radiation and concomitant and adjuvant temozolomide chemotherapy. He received bevacizumab for progression, and dose dense metronomic temozolomide was added for additional progression. He developed chronic cough and was diagnosed with B. bronchiseptica infection. This is the first reported case of B. bronchiseptica infection in a patient receiving temozolomide. The infection was likely acquired from an infected kitten. Patients receiving temozolomide should be counseled on the risks of acquiring zoonotic infections, including B. bronchiseptica, from their pets.

Active and passive immunizations with Bordetella colonization factor A protect mice against respiratory challenge with Bordetella bronchiseptica

Bordetella colonization factor A (BcfA) is an outer membrane immunogenic protein, which is critical for efficient colonization of the murine respiratory tract. These properties of BcfA prompted us to examine its utility in inducing a protective immune response against Bordetella bronchiseptica in a mouse model of intranasal infection. Mice vaccinated with BcfA demonstrated reduced pathology in the lungs and harbored lower bacterial burdens in the respiratory tract. Immunization with BcfA led to the generation of BcfA-specific antibodies in both the sera and lungs, and passive immunization led to the reduction of B. bronchiseptica in the tracheas and lungs. These results suggest that protection after immunization with BcfA is mediated in part by antibodies against BcfA. To further investigate the mechanism of BcfA-induced immune clearance, we examined the role of neutrophils and macrophages. Our results demonstrate that neutrophils are critical for anti-BcfA antibody-mediated clearance and that opsonization with anti-BcfA serum enhances phagocytosis of B. bronchiseptica by murine macrophages. We show that immunization with BcfA results in the production of gamma interferon and subclasses of immunoglobulin G antibodies that are consistent with the induction of a Th1-type immune response. In combination, our findings suggest that the mechanism of BcfA-mediated immunity involves humoral and cellular responses. Expression of BcfA is conserved among multiple clinical isolates of B. bronchiseptica. Our results demonstrate the striking protective efficacy of BcfA-mediated immunization, thereby highlighting its utility as a potential vaccine candidate. These results also provide a model for the development of cell-free vaccines against B. bronchiseptica.