Evaluation of the Role of the Bvg Intermediate Phase in Bordetella pertussis during Experimental Respiratory Infection

Abstract

pertussis may be involved in facilitating transmission between hosts. Thus, a B. pertussis mutant carrying the bvgS-I1 mutation (GMT1i) persisted at wild-type levels only in the upper murine respiratory tract. Interestingly, a bipA deletion derivative of GMT1i displayed a reduced ability to colonize the nasal cavity of mice compared with GMT1i. However, in experimental mixed infections GMT1i expressing the Bvg i phase could establish an initial colonization in the nose and trachea of mice as efficiently as GMT1, but the wild-type strain outcompeted GMT1i at a later time point at all sites of the respiratory tract, suggesting that the Bvg i phase does not serve as a phenotypic phase specialized in colonization. Finally, even though B. pertussis expresses in vitro the Bvg i phase at the human nasal temperature, anti-BipA antibodies were undetectable in a large collection of sera from pertussis patients.

The Proinflammatory Response Induced by Wild-TypeYersinia pseudotuberculosisInfection Inhibits Survival ofyopMutants in the Gastrointestinal Tract and Peyer's Patches

“…A number of mutants in a variety of bacterial pathogens survive as well as the wild-type pathogen in single-strain infections but are outcompeted by the wild-type strain in competition infections (30,36,37,55,60). Possible explanations for these results include an inability of the mutant to compete for sites of colonization or key nutrients or an inability to survive the host response to infection by the wild-type pathogen.…”

Species- and Strain-Specific Control of a Complex, Flexible Regulon by Bordetella BvgAS

“…Because intermediate-phase gene expression patterns were found to differ significantly between the two species, these phases may provide species-specific functions in addition to the putative roles in aerosol transmission and biofilm formation (25,60). Preferential expression in the Bvg i -a phase of B. bronchiseptica of genes for respiratory terminal oxidases with high oxygen affinity suggests that this phase may be optimized for survival in microaerophilic conditions, which may be encountered at the airway epithelium due to the accumulation of mucus and debris.…”

“…The Bvg Ϫ phase of B. pertussis is still relatively uncharacterized, and because B. pertussis is apparently unable to persist outside the host, this phase has been proposed to be an evolutionary remnant (9,40). The Bvg i phase is thought to be similar in B. bronchiseptica and B. pertussis (17) and may be involved in biofilm formation (25) and aerosol transmission (11,60).…”

Cross-Species Protection Mediated by a Bordetella bronchiseptica Strain Lacking Antigenic Homologs Present in Acellular Pertussis Vaccines

“…While ACT is not included in any of the Pa vaccines, we deleted cyaA because ACT is a critical virulence factor (23,54). The bipA gene was deleted based on previous reports that BipA is highly immunogenic in both naturally and experimentally infected animals (17,53). In a murine model of intranasal infection, LPaV colonized and persisted in the noses of mice.…”