Indigenous microflora and innate immunity of the head and neck.

The normal flora of the head and neck exists in a delicate balance within tightly regulated ecologic niches, counterbalanced by a highly efficient innate immune system of the host. Invasion by the normal oral flora is rare when mucosal defenses remain intact. An understanding of the indigenous microflora and the innate mucosal defense mechanisms is necessary for an appropriate evaluation of infections and therapies in this area.