Bordetella bronchiseptica in a pediatric Cystic Fibrosis center

Multifocal pneumonia caused by Bordetella bronchiseptica: Insights from a human case study

This case report describes a 43-year-old man who presented with respiratory distress and was diagnosed with an exacerbation of congestive heart failure and multifocal pneumonia caused by Bordetella bronchiseptica. Microbiological work up of a respiratory sample identified the causative organism, prompting antibiotic treatment and recommending vaccination for his dog. This case emphasizes the need to consider diverse origins in respiratory infections for effective clinical management.

Bordetella bronchiseptica diguanylate cyclase BdcB inhibits the type three secretion system and impacts the immune response

Bordetella bronchiseptica is a gram-negative bacterium that causes respiratory diseases in different animals, including mice, making B. bronchiseptica the gold-standard model to investigate host-pathogen interaction at the molecular level. B. bronchiseptica utilizes many different mechanisms to precisely regulate the expression of virulence factors. Cyclic di-GMP is a second messenger synthesized by diguanylate cyclases and degraded by phosphodiesterases that regulates the expression of multiple virulence factors including biofilm formation. As in other bacteria, we have previously shown that c-di-GMP regulates motility and biofilm formation in B. bronchiseptica. This work describes the diguanylate cyclase BdcB (Bordetella diguanylate cyclase B) as an active diguanylate cyclase that promotes biofilm formation and inhibits motility in B. bronchiseptica. The absence of BdcB increased macrophage cytotoxicity in vitro and induced a greater production of TNF-α, IL-6, and IL-10 by macrophages. Our study reveals that BdcB regulates the expression of components of T3SS, an important virulence factor of B. bronchiseptica. The Bb∆bdcB mutant presented increased expression of T3SS-mediated toxins such as bteA, responsible for cytotoxicity. Our in vivo results revealed that albeit the absence of bdcB did not affect the ability of B. bronchiseptica to infect and colonize the respiratory tract of mice, mice infected with Bb∆bdcB presented a significantly higher pro-inflammatory response than those infected with wild type B. bronchiseptica.

Conquering the host: Bordetella spp. and Pseudomonas aeruginosa molecular regulators in lung infection

When bacteria sense cues from the host environment, stress responses are activated. Two component systems, sigma factors, small RNAs, ppGpp stringent response, and chaperones start coordinate the expression of virulence factors or immunomodulators to allow bacteria to respond. Although, some of these are well studied, such as the two-component systems, the contribution of other regulators, such as sigma factors or ppGpp, is increasingly gaining attention. Pseudomonas aeruginosa is the gold standard pathogen for studying the molecular mechanisms to sense and respond to environmental cues. Bordetella spp., on the other hand, is a microbial model for studying host-pathogen interactions at the molecular level. These two pathogens have the ability to colonize the lungs of patients with chronic diseases, suggesting that they have the potential to share a niche and interact. However, the molecular networks that facilitate adaptation of Bordetella spp. to cues are unclear. Here, we offer a side-by-side comparison of what is known about these diverse molecular mechanisms that bacteria utilize to counteract host immune responses, while highlighting the relatively unexplored interactions between them.

Antibiotic multidrug resistance in the cystic fibrosis airway microbiome is associated with decreased diversity

Background

Cystic fibrosis (CF) is associated with significant morbidity and early mortality due to recurrent acute and chronic lung infections. The chronic use of multiple antibiotics increases the possibility of multidrug resistance (MDR). Antibiotic susceptibility determined by culture-based techniques may not fully represent the resistance profile. The study objective was to detect additional antibiotic resistance using molecular methods and relate the presence of MDR to airway microbiome diversity and pulmonary function.

Methods

Bacterial DNA was extracted from sputum samples and amplified for the V4 region of the 16S rRNA gene. An qPCR array was used to detect antibiotic resistance genes. Clinical culture results and pulmonary function were also noted for each encounter.

Results

Six study participants contributed samples from 19 encounters. Those samples with MDR (n = 7) had significantly lower diversity measured by inverse Simpson's index than those without (n = 12) (2.193 ± 0.427 vs 6.023 ± 1.564, p = 0.035). Differential abundance showed that samples with MDR had more Streptococcus (p = 0.002) and Alcaligenaceae_unclassified (p = 0.002). Pulmonary function was also decreased when MDR was present (FEV₁, 51 ± 22.9 vs 77 ± 26.7, p = 0.054; FVC, 64.5 ± 22.7 vs 91.6 ± 27.7, p = 0.047).

Conclusions

The presence of MDR within the CF airway microbiome was associated with decreased microbial diversity, the presence of Alcaligenes, and decreased pulmonary function.

Bordetella bronchiseptica in non-cystic fibrosis bronchiectasis

Bordetella bronchiseptica is a rare pulmonary infection, often associated with zoonotic transmission. It has been described in immunocompromised patients and those with underlying pulmonary disease. However, there are no case series describing the spectrum of disease caused by Bordetella bronchiseptica in patients with non-cystic fibrosis bronchiectasis. Here, we report three cases of Bordetella bronchiseptica infection in patients with non-cystic fibrosis bronchiectasis and highlight the pathophysiology of the microbe. While the clinical presentation can be quite variable, it is important to note that Bordetella bronchiseptica can be a cause of pulmonary exacerbations and can be difficult to eradicate.

Cystic Fibrosis Mice Develop Spontaneous Chronic Bordetella Airway Infections

Chronic pulmonary disease and infection is the primary cause of morbidity and mortality in people with cystic fibrosis (CF). Though Pseudomonas aeruginosa, is most commonly found in the airways of individuals with CF, there is increasing appreciation for the diversity of the CF microbiome, including other taxa such as Bordetella. Here we describe the identification and impact of Bordetella pseudohinzii infection in CF mice, which previously have not been thought to develop spontaneous airway infections. We determined that CF mice are more susceptible to the B. pseudohinzii infections, and less able to resolve the infection than non-CF mice. Moreover, in both CF and non-CF mice, B. pseudohinzii infections lead to markedly reduced respiratory rates and a CF-specific immune response. These results establish the CF mouse model as an important tool for the study of CF-relevant infection and highlight the potential contribution of Bordetella to CF clinical pathology.

Bordetella bronchiseptica pneumonia in a patient with lung cancer; a case report of a rare infection

BACKGROUND

Bordetella bronchiseptica (B.bronchiseptica) is a frequent cause of respiratory infections in animals but rarely causes serious infection in humans. We present a rare case of B. bronchiseptica pneumonia in a patient with lung cancer.

CASE PRESENTATION

A 52-year-old white male with non small cell lung cancer developed fever during treatment with nivolumab. A persistent productive cough and a deterioration in his clinical condition led to his hospitalization for evaluation. Bronchoscopy was performed and a diagnosis of B. bronchiseptica pneumonia was made. The infection was successfully managed by antiobiotic therapy.

CONCLUSIONS

B. bronchiseptica is a pathogen that can cause serious infection in humans, especially in immunocompromised or immunoincompetent individuals. In our patient it showed unusual resistance to cephalosporins and poor sensitivity to amikacin. To our knowledge this is the first case of such an infection in a lung cancer patient undergoing treatment with nivolumab. When B. bronchiseptica is identified, the possibility of a nosocomial transmission must be considered.

Strong incidence of Pseudomonas aeruginosa on bacterial rrs and ITS genetic structures of cystic fibrosis sputa

Cystic fibrosis (CF) lungs harbor a complex community of interacting microbes, including pathogens like Pseudomonas aeruginosa. Meta-taxogenomic analysis based on V5-V6 rrs PCR products of 52 P. aeruginosa-positive (Pp) and 52 P. aeruginosa-negative (Pn) pooled DNA extracts from CF sputa suggested positive associations between P. aeruginosa and Stenotrophomonas and Prevotella, but negative ones with Haemophilus, Neisseria and Burkholderia. Internal Transcribed Spacer analyses (RISA) from individual DNA extracts identified three significant genetic structures within the CF cohorts, and indicated an impact of P. aeruginosa. RISA clusters Ip and IIIp contained CF sputa with a P. aeruginosa prevalence above 93%, and of 24.2% in cluster IIp. Clusters Ip and IIIp showed lower RISA genetic diversity and richness than IIp. Highly similar cluster IIp RISA profiles were obtained from two patients harboring isolates of a same P. aeruginosa clone, suggesting convergent evolution in the structure of their microbiota. CF patients of cluster IIp had received significantly less antibiotics than patients of clusters Ip and IIIp but harbored the most resistant P. aeruginosa strains. Patients of cluster IIIp were older than those of Ip. The effects of P. aeruginosa on the RISA structures could not be fully dissociated from the above two confounding factors but several trends in these datasets support the conclusion of a strong incidence of P. aeruginosa on the genetic structure of CF lung microbiota.

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.

Pneumonia caused by Bordetella bronchiseptica in two HIV-positive patients

CONTEXT AND OBJECTIVE

Bordetella bronchiseptica (BB) is a Gram-negative coccobacillus responsible for respiratory diseases in dogs, cats and rabbits. Reports on its development in humans are rare. However, in immunosuppressed patients, especially in those with the immunodeficiency virus (HIV), BB can cause severe pulmonary infections. We report on two cases of pneumonia caused by BB in HIV-positive male patients in a university hospital.

CASE REPORT

The first case comprised a 43-year-old patient who was admitted presenting chronic leg pain and coughing, with suspected pneumonia. BB was isolated from sputum culture and was successfully treated with trimethoprim/sulfamethoxazole in association with levofloxacin. The second case comprised a 49-year-old patient who was admitted presenting fever, nausea, sweating and a dry cough, also with suspected pneumonia. BB was isolated from sputum culture, tracheal secretions and bronchoalveolar lavage. The disease was treated with ciprofloxacin but the patient died.

CONCLUSION

BB should be included in the etiology of pneumonia in immunodeficient HIV patients. As far as we know, these two were the first cases of pneumonia due to BB to occur in this university hospital.

Cilia-associated bacteria in fatal Bordetella bronchiseptica pneumonia of dogs and cats

Bordetella bronchiseptica frequently causes nonfatal tracheobronchitis, but its role in fatal pneumonia is less recognized. Our study evaluated histologic identification of cilia-associated bacteria as a method for diagnosis of B. bronchiseptica pneumonia. Cases of fatal bronchopneumonia were studied retrospectively, excluding neonates and cases of aspiration pneumonia, minor lung lesions, or autolysis. The study population comprised 36 canine and 31 feline cases of bronchopneumonia. B. bronchiseptica was identified in 8 of 36 canine and 14 of 31 feline cases based on immunohistochemistry (IHC) using serum from a rabbit hyperimmunized with pertactin, PCR testing (Fla2/Fla12), and/or bacterial culture data when available. Of these, IHC was positive in 4 canine and 7 feline cases, PCR was positive in 8 canine and 14 feline cases, and B. bronchiseptica was isolated in 2 of 5 canine and 3 of 9 feline cases tested. Examination of histologic sections stained with hematoxylin and eosin revealed bronchial cilia-associated bacteria in 4 of 36 canine and 5 of 31 feline cases; these were all positive by IHC and PCR. The presence of cilia-associated bacteria had been noted in the pathology report for only 2 of these 9 cases. Thus, the presence of cilia-associated bacteria seems frequently overlooked by pathologists, but is a diagnostically significant feature of B. bronchiseptica pneumonia. A specific diagnosis of B. bronchiseptica pneumonia is important because it suggests primary or opportunistic bacterial pneumonia rather than aspiration pneumonia, and because of the risk of animal-to-animal transmission of B. bronchiseptica, the availability of vaccines for disease prevention, and the potential zoonotic risk to immunocompromised pet owners.

Persistent Bordetella bronchiseptica infection in a child with cystic fibrosis: Relationship to bacterial phenotype

Bordetella bronchiseptica is an opportunistic bacteria infecting the respiratory tract of patients with cystic fibrosis. We present a case of B. bronchiseptica chronic pulmonary infection and documentation of some phenotypic attributes of the clinical isolates allowing the microorganism to induce progressive respiratory degradation and chronic sputum colonization. We recommend implementing adequate treatment aiming eradication from the first isolation of this bacterium. We advise for practices that minimize opportunities for zoonotic transmission of B. bronchiseptica from family pets.

Draft Genome Assembly of Bordetella bronchiseptica ATCC 10580, a Historical Canine Clinical Isolate

We present the scaffolded genome of Bordetella bronchiseptica ATCC 10580, assembled into 98 contigs. This 5.1-Mb assembly (68.2% G+C content) contains 4,870 coding regions. The strain was originally isolated from canine lung tissue and is used in quality control testing.

Comparative analyses of a cystic fibrosis isolate of Bordetella bronchiseptica reveal differences in important pathogenic phenotypes

Bordetella bronchiseptica is a Gram-negative bacterium that infects and causes disease in a wide variety of animals. B. bronchiseptica also infects humans, thereby demonstrating zoonotic transmission. An extensive characterization of human B. bronchiseptica isolates is needed to better understand the distinct genetic and phenotypic traits associated with these zoonotic transmission events. Using whole-genome transcriptome and CGH analysis, we report that a B. bronchiseptica cystic fibrosis isolate, T44625, contains a distinct genomic content of virulence-associated genes and differentially expresses these genes compared to the sequenced model laboratory strain RB50, a rabbit isolate. The differential gene expression pattern correlated with unique phenotypes exhibited by T44625, which included lower motility, increased aggregation, hyperbiofilm formation, and an increased in vitro capacity to adhere to respiratory epithelial cells. Using a mouse intranasal infection model, we found that although defective in establishing high bacterial burdens early during the infection process, T44625 persisted efficiently in the mouse nose. By documenting the unique genomic and phenotypic attributes of T44625, this report provides a blueprint for understanding the successful zoonotic potential of B. bronchiseptica and other zoonotic bacteria.