Aggregatibacter actinomycetemcomitans: The virulence factors and relation to persistence biofilm formation

Periodontitis is an infectious and inflammatory condition that is associated with subgingival biofilms in tooth-supporting tissues. Among the several hundred isolated organisms in the oral cavity, one of the most isolated bacteria from infected periodontal pockets are Aggregatibacter actinomycetemcomitans. It is a Gram-negative, facultative anaerobic bacillus that causes juvenile (localized aggressive periodontitis) and adolescent periodontal diseases. The development of biofilms is an essential factor in pathogenesis for A. actinomycetemcomitans. The early attachment of A. actinomycetemcomitans to abiotic surfaces relies on its protein-like fimbriae. This organism's ability to form tenacious biofilms can determine its survival and progression. A. actinomycetemcomitans, a pathogen not solely in periodontal but also involve in some systemic infections. This species has several virulence factors and genes that contribute to its oral cavity survival and, worst of all, cause bone resorption and tooth loss. Genetic diversity between the different A. actinomycetemcomitans isolates are great, and their ability to express and release virulence factors varies. In this review article, we discuss about the potential virulence factors and candidates genes for A. actinomycetemcomitans and their roles within periodontal disease by revealing their functional biology in facilitating attachment to oral surfaces, hindering protection of the host and causing inflammation and degradation of tissue.