Oxantel Disrupts Polymicrobial Biofilm Development of Periodontal Pathogens

Abstract

Bacterial pathogens commonly associated with chronic periodontitis are the spirochete Treponema denticola and the Gramnegative, proteolytic species Porphyromonas gingivalis and Tannerella forsythia. These species rely on complex anaerobic respiration of amino acids, and the anthelmintic drug oxantel has been shown to inhibit fumarate reductase (Frd) activity in some pathogenic bacteria and inhibit P. gingivalis homotypic biofilm formation. Here, we demonstrate that oxantel inhibited P. gingivalis Frd activity with a 50% inhibitory concentration (IC 50 ) of 2.2 M and planktonic growth of T. forsythia with a MIC of 295 M, but it had no effect on the growth of T. denticola. Oxantel treatment caused the downregulation of six P. gingivalis gene products and the upregulation of 22 gene products. All of these genes are part of a regulon controlled by heme availability. There was no large-scale change in the expression of genes encoding metabolic enzymes, indicating that P. gingivalis may be unable to overcome Frd inhibition. Oxantel disrupted the development of polymicrobial biofilms composed of P. gingivalis, T. forsythia, and T. denticola in a concentration-dependent manner. In these biofilms, all three species were inhibited to a similar degree, demonstrating the synergistic nature of biofilm formation by these species and the dependence of T. denticola on the other two species. In a murine alveolar bone loss model of periodontitis oxantel addition to the drinking water of P. gingivalis-infected mice reduced bone loss to the same level as the uninfected control.

The Role of Treponema denticola Motility in Synergistic Biofilm Formation With Porphyromonas gingivalis

“…Static biofilm assays were carried out essentially as previously described (Dashper et al, 2014). Briefly, T. denticola and P. gingivalis cells were grown to exponential phase and diluted with fresh pre-reduced OBGM to A 650 of 0.15 where necessary.…”

The interplay between iron, haem and manganese in Porphyromonas gingivalis

“…FrdB contains a 2Fe-2S, a 4Fe-4S and a 3Fe-4S cluster, whilst FrdC contains two haem molecules [62] and appears to be the main user of haem as a redox cofactor in the anaerobic respiratory chain of P. gingivalis [64]. Inhibition of fumarate reductase activity by oxantel pamoate stopped the growth of the bacterium and strongly inhibited biofilm formation, demonstrating the essential role of this enzyme in P. gingivalis metabolism [68,69].…”

Mecanismos de vasorelaxamento envolvidos na resposta vasomotora >i<in vitro>/i< de anéis de artéria mesentérica provenientes de ratos com periodontite induzida por ligadura.

“…Em pacientes com periodontite, as bactérias mais encontradas e estudadas são P. gingivalis, T. forsythia, a espiroqueta T. denticola e Actinobacillus (A) actinomycetemcomitans (Mandell, Socransky, 1981;Moore, Moore, 1994;Dashper et al, 2014). A presença de patógenos capazes de invadir a estrutura e alterar função do epitélio juncional, responsável por manter a saúde periodontal e sendo esse um obstáculo eficiente contra bactérias e seus produtos, pode ser uma das explicações para a associação da periodontite com possíveis doenças em órgãos distantes (Nanci, Bosshardt, 2006;Dashper et al, 2014;Salminen, 2014).…”