Aggregatibacter actinomycetemcomitans

This reprint is devoted to the oral microbe Aggregatibacter actinomycetemcomitans and its associated distinctive form of rapidly destructive periodontitis that results in early tooth loss, predominantly occurring in adolescents and children of African descent. Three chapters are related to the biological and clinical characteristics of the disease, while six chapters are devoted genetic features uniquely suited for local disruption of the host’s homeostatic balance. The final two chapters illustrate how a deep molecular understanding of A. actinomycetemcomitans has been used to develop therapies for diseases such as staphylococcal infections and leukemias. The reprint illustrates A. actinomycetemcomitans’s 1) highly adaptable nature, 2) its influence on its microbial cohorts, 3) its modulation of local host responsiveness, and 4) its relationship to tissue damage, microbial survival tactics, and metabolic and competitive ecological strategies. These microbe-related processes can be applied to other infectious diseases. The Damage–Response Framework is illustrated as the most appropriate way to consider this microbe, its effect on its host, and the relationship of time to the extent of damage or repair.