A

ctinobacillus actinomycetemcomitans, which we will refer to simply as Aa from now on (because I'm not typing that out every damn time) is one of the "HACEK" grouping of Gram negative organisms that are all part of the normal human orophayngeal and/or urogenital flora. This organism (and the others) can, given the right circumstances, be found in association with endocarditis, bacteremia, and wound infections. Aa is a slow bugger to grow, often taking 48 to 72 hours, and forget about growing it on anything but enriched media. The most common infection associated with Aa is subacute bacterial endocarditis, though it is also blazing a trail in the area of periodontal disease as well. Aa has a decent sized virulence factor arsenal, including a leukotoxin, a PMN chemotaxis-inhibiting factor, resistance to complement killing, and bone resorption-inducing toxin.