The role of black‐pigmented Bacteroides in human oral infections

Abstract

Today, 10 black‐pigmented Bacteroides (BPB) species are recognized. The majority of these species can be isolated from the oral cavity. BPB species are involved in anaerobic infections of oral and non‐oral sites. In the oral cavity. BPB species are associated with gingivitis, periodontitis, endodontal infections and odontogenic abscesses. Cultural studies suggest a specific role of the various BPB species in the different types of infection. Bacteroides gingivalis is closely correlated with destructive periodontitis in adults as well as in juveniles. Bacteroides intermedius seems to be less specific since it is found in gingivitis, periodontitis, endodontal infections and odontogenic abscesses. The recently described Bacteroides endodontalis is closely associated with endodontal infections and odontogenic abscesses of endodontal origin. There are indications that these periodontopathic BPB species are only present in the oral cavity of subjects suffering from periodontal breakdown, being absent on the mucosal surfaces of subjects without periodontal breakdown. BPB species associated with healthy oral conditions are Bacteroides melaninogenicus, Bacteroides denticola and Bacteroides loescheii. There are indications that these BPB species are part of the normal indigenous oral microflora. Many studies in the past have documented the pathogenic potential and virulence of BPB species. This virulence can be explained by the large numbers of virulence factors demonstrated in this group of microorganisms. Among others, the proteolytic activity seems to be one of the most important features. Several artificial substrates as well as numerous biological proteins are degraded. These include anti‐inflammatory proteins such as alpha‐2‐macroglobulin, alpha‐1‐antitrypsin, C3 and C5 complement factors and immunoglobulins. B. gingivalis is by far the most proteolytic species, followed by B. endodontalis. Like other bacteria, the lipopolysaccharide of B. gingivalis has shown to be active in bone resorption in vitro and is capable in stimulating interleukin‐1 production in human peripheral monocytes. Based on the well documented association with periodontal disease and the possession of relevant virulence factors. BPB species must be considered as important micro‐organisms in the etiology of oral infections. B. gingivalis seems to be the most pathogenic and virulent species.

Th1 Immune Response Promotes Severe Bone Resorption Caused by Porphyromonas gingivalis

“…The pathogen Porphyromonas gingivalis has been associated with active disease in both systems. [1][2][3][4][5][6] In periodontal disease, an epithelial barrier separates the microbial biofilm from host tissues, whereas in periapical periodontitis; there is direct tissue invasion and parenteral contact of bacteria with the host immune system. Remarkably, actual microbial invasion of bone rarely occurs in periapical periodontitis, suggesting that the local immune response contains the infection but at the same time mediates bone resorption.…”

Sub-Micrometric Liposomes as Drug Delivery Systems in the Treatment and Periodontitis

“…In the 70's, Nisengard et aI., van Winkelhoff et aI. and others highlighted the central role of bacteria in causing periodontitis (33,34). The goal of our study was to prepare sub-micrometer liposomes able to diffuse in dentinal tubules, where bacteria hide as colonies within the entire length ofthe tubule.…”

Identification of putative pathogens in acute endodontic infections by PCR based on 16S rDNA

“…본 연구에서는 P. nigrescens 가 18.2%로 나타났고, P. intermedia가 15.9%로 나타나 치수 및 치근단 질환에서 두 세균 종들의 발현 빈도는 비슷 한 양상을 보였다( Table 2). P. endodontalis와 P. gingivalis가 급성 증상과 관련이 있다고 알려진 반면, 일반적으 로 P. intermedia와 P. nigrescens는 급성 증상과 무 증상 에서 두루 발견된다고 알려져 있다 10,12,13) . 본 연구의 결과를 볼 때, 이들 세균이 증상과 어느 정도 관련이 있기는 하나, 확실한 관련성을 밝히기 위해서는 앞으로 더 많은 연구가 필요할 것으로 사료된다.…”