ABSTRACT
Anaerobic bacteria live in environments with reduced oxygen levels and include both commensals microorganisms and microbial pathogens. Anaerobic pathogens are frequently components of the resident (normal) microflora. They are opportunistic pathogens that can cause disease if, for example, they are traumatically inoculated into adjacent sites or by elimination of microbial competitors following antibiotic therapy. Resident anaerobic bacteria can also become pathogenic by gaining access to the bloodstream and being transported from their normal ecologic niche to distant sites in the body. Anaerobic bacteria that normally reside in the human oral cavity—members of the genera Porphyromonas and Prevotella— can be found in atherosclerotic plaques (Haraszthy et al., 2000; Kozarov et al., 2006; Zhong et al., 2008; Chhibber-Goel et al., 2016). A number of oral species have been associated with atherosclerotic plaques including A. actinomycetemcomitans, C. pneumoniae, C. rectus, E. corrodens, E. hormaechei, F. necrophorum, F. nucleatum, H. pylori, M. pneumoniae, P. aeruginosa, P. endodontalis, P. gingivalis, P. intermedia, P. luteola, P. nigrescens, S. gordonii, S. mitis, S. mutans, S. oralis, S. sanguinis, T. denticola, T. forsythia, and Veillonella (Chhibber-Goel et al., 2016). Many species, including Porphyromonas gingivalis and Prevotella intermedia, have been identified by polymerase chain reaction (PCR) amplification of bacterial 16S rDNA and 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.
