Phenotypic Modulation of the Virulent Bvg Phase Is Not Required for Pathogenesis and Transmission of Bordetella bronchisepticain Swine
In: Infection and Immunity, Jg. 80 (2012-03-01), Heft 3, S. 1025-1036
Online
serialPeriodical
Zugriff:
The majority of virulence gene expression in Bordetellais regulated by a two-component sensory transduction system encoded by the bvglocus. In response to environmental cues, the BvgAS regulatory system controls expression of a spectrum of phenotypic phases, transitioning between a virulent (Bvg+) phase and a nonvirulent (Bvg-) phase, a process referred to as phenotypic modulation. We hypothesized that the ability of Bordetella bronchisepticato undergo phenotypic modulation is required at one or more points during the infectious cycle in swine. To investigate the Bvg phase-dependent contribution to pathogenesis of B. bronchisepticain swine, we constructed a series of isogenic mutants in a virulent B. bronchisepticaswine isolate and compared each mutant to the wild-type isolate for its ability to colonize and cause disease. We additionally tested whether a BvgAS system capable of modulation is required for direct or indirect transmission. The Bvg-phase-locked mutant was never recovered from any respiratory tract site at any time point examined. An intermediate phase-locked mutant (Bvgi) was found in numbers lower than the wild type at all respiratory tract sites and time points examined and caused limited to no disease. In contrast, colonization of the respiratory tract and disease caused by the Bvg+phase-locked mutant and the wild-type strain were indistinguishable. The Bvg+phase-locked mutant transmitted to naïve pigs by both direct and indirect contact with efficiency equal to that of the wild-type isolate. These results indicate that while full activation of the BvgAS regulatory system is required for colonization and severe disease, it is not deleterious to direct and indirect transmission. Overall, our results demonstrate that the Bvg+phase is sufficient for respiratory infection and host-to-host transmission of B. bronchisepticain swine.
Titel: |
Phenotypic Modulation of the Virulent Bvg Phase Is Not Required for Pathogenesis and Transmission of Bordetella bronchisepticain Swine
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Autor/in / Beteiligte Person: | Nicholson, Tracy L. ; Brockmeier, Susan L. ; Loving, Crystal L. ; Register, Karen B. ; Kehrli, Marcus E. ; Stibitz, Scott E. ; Shore, Sarah M. |
Link: | |
Zeitschrift: | Infection and Immunity, Jg. 80 (2012-03-01), Heft 3, S. 1025-1036 |
Veröffentlichung: | 2012 |
Medientyp: | serialPeriodical |
ISSN: | 0019-9567 (print) ; 1098-5522 (print) |
DOI: | 10.1128/IAI.06016-11 |
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