Microbial Interaction of Periodontopathic Bacterium Porphyromonas gingivalis and HIV-Possible Causal Link of Periodontal Diseases to AIDS Progression-

A wide variety of infections, including bacteria, viruses, fungi and protozoa occur in the immunocompromised condition associated with human immunodeficiency virus type 1 (HIV-1) infection and acquired immunodeficiency syndrome (AIDS). Although these opportunistic infections are believed to arise as an effect of the immunodeficiency, these microbes sometimes promote the disease progression of HIV-1 infection by enhancing viral replication or modulating host immune responses. Here we review the experimental and clinical evidence supporting such causal relationships associated with periodontogenic bacteria. Periodontal disease, caused by subgingival infection with oral anaerobic bacteria, typically Porphyromonas gingivalis (P. gingivalis) belonging to the phylum Bacteroidetes, is found worldwide and is one of the most prevalent microbial diseases of mankind. Emerging evidence implicates the involvement of P. gingivalis infection in the progression of HIV-1 infection. We demonstrate that P. gingivalis can induce HIV-1 reactivation via chromatin modification, and that the bacterial metabolite butyric acid produced in anaerobic conditions is responsible for this effect. These findings suggest that periodontal diseases could act as a risk factor for HIV-1 reactivation in infected individuals and might contribute to AIDS progression. Furthermore, it would imply that prevention and early treatment of periodontitis involving P. gingivalis infection could effectively block further clinical progression of AIDS.