Porphyromonas gingivalis outer membrane vesicles promote bacterial resistance to chlorhexidine

Porphyromonas gingivalis has been frequently associated with some types of periodontal diseases and possesses various mechanisms favoring the pathogenic process. It has been recently observed that vesicles elaborated by P. gingivalis are able to protect bacteria from the bactericidal activity of human serum. The aim of the present investigation was to evaluate the ability of vesicles from P. gingivalis in protecting oral bacteria against chlorhexidine. Data indicate that vesicles released by P. gingivalis may bind chlorhexidine, thus allowing protection for itself and for other oral bacterial species. It has also been demonstrated that lipopolysaccharides are the major component involved in the binding of chlorhexidine by vesicles. The mechanism of resistance reported in this study indicates that bacterial interactions in the oral cavity may influence the sensitivity of microbes.