Other anaerobic bacteria bacteroides, porphyromonas, prevotella, tannerella, fusobacterium, and Gram-Positive Anaerobic Cocci

Anaerobic bacteria live in environments with reduced oxygen levels and include both commensals and pathogens. Anaerobic pathogens are frequently constituents of the resident microflora and, therefore, opportunistic pathogens, which can cause disease if inoculated by trauma into adjacent sites or by overgrowth following the elimination of microbial competitors following antibiotic therapy. Endogenous anaerobic bacteria may also become pathogenic by gaining access to the bloodstream-bacteremia-and being transported from their normal ecologic niche to distant sites in the body. Examples include the presence of anaerobic bacteria that normally reside in the human oral cavity-members of the genera Porphyromonas and Prevotella-in atherosclerotic plaques (Haraszthy et al., 2000; Kozarov et al., 2006). A number of species, including Porphyromonas gingivalis and Prevotella intermedia, have been identified by polymerase chain reaction (PCR) amplification of bacterial 16S rDNA and DNA hybridization using species-specific DNA probes. Consequently, anaerobic species such as these that have their primary ecologic niche in dental plaque in the human oral cavity are thought to gain access to the blood stream and become part of atherosclerotic plaques, possibly playing a role in their formation.