Tools of Aggregatibacter actinomycetemcomitans to Evade the Host Response

Abstract

Periodontitis is an infection-induced inflammatory disease that affects the tooth supporting tissues, i.e., bone and connective tissues. The initiation and progression of this disease depend on dysbiotic ecological changes in the oral microbiome, thereby affecting the severity of disease through multiple immune-inflammatory responses. Aggregatibacter actinomycetemcomitans is a facultative anaerobic Gram-negative bacterium associated with such cellular and molecular mechanisms associated with the pathogenesis of periodontitis. In the present review, we outline virulence mechanisms that help the bacterium to escape the host response. These properties include invasiveness, secretion of exotoxins, serum resistance, and release of outer membrane vesicles. Virulence properties of A. actinomycetemcomitans that can contribute to treatment resistance in the infected individuals and upon translocation to the circulation, also induce pathogenic mechanisms associated with several systemic diseases.

Rheumatoid Arthritis-Associated Mechanisms of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans

“…A more detailed analysis of the pathogenic mechanisms associated with the induction of periodontitis by Aa have been reviewed recently. [203]…”

Virulence and Pathogenicity Properties of Aggregatibacter actinomycetemcomitans

“…Its lipopolysaccharide is quite special in that the immunological responses elicited by the host can be used in classifying (serotyping) the virulence identity of each one of its strains [7]. More recently identified cytokine-binding molecules add to its potential virulence factors, suggesting additional pathogenicity mechanisms by which it can manipulate the host [8]. A. actinomycetemcomitans is also equipped with a wealth of outer membrane vesicles, like all Gram-negative species, which might confer special virulence properties to this species [9].…”

43-Year Temporal Trends in Immune Response to Oral Bacteria in a Swedish Population

“…This is especially noteworthy, as a significant reduction in caries and periodontitis has occurred and attendance of regular dental care increased in the targeted population over the study period. Systemic antibody responses to colonizing or invading bacteria indicate activation of the host response to current or past presence of a species [29,30]. One potential hypothesis behind a changed systemic antibody response would be a change in the abundance of the triggering bacterium, but it is not obvious that the levels of immunoreactivity reflect the bacterial load in the oral cavity [31].…”