Comparative Analyses of a Cystic Fibrosis Isolate of Bordetella bronchiseptica Reveal Differences in Important Pathogenic Phenotypes

Abstract

bBordetella 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.

The Protein BpsB Is a Poly-β-1,6-N-acetyl-d-glucosamine Deacetylase Required for Biofilm Formation in Bordetella bronchiseptica

“…In contrast, B. bronchiseptica has a broad host range, colonizing and causing disease in a wide variety of animals. B. bronchiseptica can also infect immunocompromised and healthy humans thereby demonstrating zoonotic transmission (2,3).…”

“…Several studies have shown that Bordetella spp. form biofilms on artificial surfaces (3,(7)(8)(9)(10)(11)(12) and that both B. pertussis and B. bronchiseptica form biofilms in the mouse respiratory tract (13)(14)(15)(16)(17). A biofilm is composed of a complex extracellular matrix that encases microcolonies of bacteria (18,19), which limits the diffusion of antimicrobials and occludes phagocytosis (20).…”

Bordetella Colonization Factor A (BcfA) elicits protective immunity againstBordetella bronchisepticain the absence of an additional adjuvant

“…Furthermore, allelic variants of Prn in B. bronchiseptica are reported(46, 47), implying that Prn-specific responses may not be protective due to antigenic drift among circulating strains. We showed previously that B. bronchiseptica isolates from dogs (including MBORD 685 used in this study), cats, horses, pigs, and humans highly express BcfA (10, 24). Production of BcfA by strains isolated from companion and food-producing animals strengthens its utility as a protective antigen in a novel vaccine, a possibility supported by our data showing that both BcfA alone and BcfA/FHA/Prn immunizations reduced MBORD 685 bacterial CFUs.…”

“…B. bronchiseptica is also increasingly isolated from immunocompromised humans such as those with HIV/AIDS, cancer, or cystic fibrosis. In many of these cases, the infections are linked to exposure to pets with B. bronchiseptica (8–10).…”

Porcine Respiratory Disease Complex and Biofilms

“…Infections with this microorganism are transmitted by aerosol and bacteria can be localized invading the epithelial cells of the respiratory tract [83], where the damage to the respiratory tract is fundamentally caused by dermonecrotic toxins [86]. Several recent reports have demonstrated the isolation of B. bronchiseptica from cystic fibrosis (CF) patients [87].…”