Oral ecology and person‐to‐person transmission of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis

Abstract

The ecological characteristics of the oral cavity are dissimilar for A. actinomycetemcomitans and for P. gingivalis, as judged by differences in their colonization preferences and patterns, associations with periodontal disease parameters, relationships with the subgingival microbiota and the type of periodontitis and their clonal persistence in the oral cavity. These features also suggest that as a periodontal pathogen, A. actinomycetemcomitans is different from P. gingivalis. Probably in most infected individuals, low levels of A. actinomycetemcomitans can persist for years in equilibrium with the host and the resident oral microbiota. However, it is well established that A. actinomycetemcomitans can cause disease in some individuals or in some circumstances when the regulatory mechanisms are unable to maintain homeostasis in the ecosystem. Elevated A. actinomycetemcomitans proportions of the biota can be regarded as a sign of ecological imbalance, leading to increased risk of periodontal destruction. There is also evidence showing elevated pathogenic potential of certain A. actinomycetemcomitans clones. Although A. actinomycetemcomitans seems to be relatively rarely transmitted between cohabiting adults, transmission can occur to periodontally healthy children of A. actinomycetemcomitans-positive parents. Parents and children may share factors that promote successful oral colonization of A. actinomycetemcomitans, or the window of opportunity is in childhood. Therefore, to prevent parent-child transmission of A. actinomycetemcomitans, bacterium-positive parents of young children are optimal targets for enhanced information and treatment. In selected populations, screening for specific clones of A. actinomycetemcomitans has been employed in prevention of peridontitis. Future research aiming at finding the reasons which cause the changes in the oral homeostasis to allow the growth of A. actinomycetemcomitans may give insight into novel prevention strategies for A. actinomycetemcomitans-associated periodontitis. Compared with A. actinomycetemcomitans, P. gingivalis shows a different pattern of coexistence with the host. In periodontal health or in children, P. gingivalis is absent or only rarely detected. When present, P. gingivalis is commonly recovered in high numbers from dentitions exhibiting inflamed periodontitis and poor oral hygiene. Contrary to A. actinomycetemcomitans, the data on the vertical transmission of P. gingivalis are limited. The major infection route of P. gingivalis seems to be between adults, indicating that P. gingivalis commonly colonizes in an established oral microbiota. These characteristics suggest that the degree of tolerance between P. gingivalis and the host is inferior to that between A. actinomycetemcomitans and the host. It appears that the association of P. gingivalis with disease is a rule rather than an accidental incident. On these grounds, it seems that the host-P. gingivalis relationship approaches antibiosis. Since P. gingivalis infection is related to a typical periodonta...

Molecular analysis of bacteria in periodontitis: evaluation of clone libraries, novel phylotypes and putative pathogens

“…Accordingly, Paster et al (2001) found the species only once; Sakamoto et al (2000) did not find it at all in their clone populations. Furthermore, culture studies of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans showed that Actinobacillus actinomycetemcomitans occurs in lower proportions than Porphyromonas gingivalis (see review by Asikainen & Chen, 1999).…”

Genomic distribution and functions of uptake signal sequences in Actinobacillus actinomycetemcomitans

“…The Gram-negative, capnophilic bacterium Actinobacillus actinomycetemcomitans, a member of the family Pasteurellaceae, is implicated as a major causative agent of localized aggressive periodontitis and other forms of periodontitis (Asikainen & Chen, 1999;Slots, 1999). A. actinomycetemcomitans is naturally competent for transformation (Fujise et al, 2004;Tønjum et al, 1990;Wang et al, 2002Wang et al, , 2003.…”

Antigenically Diverse Reference Strains and Autologous Strains ofActinobacillus actinomycetemcomitansAre Equally Efficient Antigens in Enzyme-Linked Immunosorbent Assay Analysis

“…In industrialized countries, oral colonization by A. actinomycetemcomitans is most commonly monoclonal (4). Additionally, spontaneous or treatment-induced changes in an A. actinomycetemcomitans clone(s) are rare in individuals persistently culture positive for the species (24; W. Z. Chen, S. Rich, and C. Chen.…”