Name Bench ID Date 
Higher order taxa
Bacteria – Bacteroidetes – Bacteroidia – Bacteroidales – Porphyromonadaceae - Porphyromonas - P. gingivalis
Species name and type strain (consult LPSN http://www.bacterio.net/index.html for this information)
Description and significance
Porphyromonas gingivalis is an obligately aerobic, gram-negative bacterium belonging to the phylum Bacteroidetes (2). Characterised by its rod shaped morphology, it is a non-spore bearing and non-motile bacterium most commonly inhabiting the oral cavity (2). Recognised as an opportunistic pathogen, P. gingivalis is capable of living in commensal harmony with the host (5). Termed as a pathobiont, the bacterium can cause episodes of diseases when a change in the ecological balance of the periodontal microenvironment transpires (5,14). Although the bacterium is capable of existing as a commensal organism, certain strains are known to be more virulent and pathogenic than others (5). Virulent strains have found to include, W83, W50, ATCC 49417 and A7A1 (6,7). Avirulent strains include ATCC 381, 33277 and 23A4 (6,7). In vitro studies of the bacterium have found cells cultured in broth with a size range from 0.5 by 1 to 2 μm (2). Cells grown on a solid media showed coccobacilli or very short rod structures (2). On blood agar plates, the bacterium forms black-pigmented colonies, predominately smooth, shiny and convex with a diameter between 1 to 2 mm (2, 12).
Typically found in the oral cavity of individuals, P. gingivalis has been implicated with periodontal diseases, most commonly associated with chronic periodontitis. A report from the Centres for Disease Control and Prevention (CDC) recorded 47. 2 % of adults in the United Stated aged 30 years or older have experienced some form of periodontal disease (8). In light of this information, recent studies have also reported that P. gingivalis is associated with systematic diseases, including cardiovascular diseases, rheumatoid arthritis and decreased kidney function (4). Studies underlying the molecular mechanisms behind the bacterial pathogenesis are key to design effective treatments. Consequently reducing the potential development of inflammatory diseases that arise as a secondary consequence of periodontitis.
Select a strain for which genome information (e.g. size, plasmids, distinct genes, etc.) is available.
Cell structure and metabolism
Cell wall, biofilm formation, motility, metabolic functions.
Aerobe/anaerobe, habitat (location in the oral cavity, potential other environments) and microbe/host interactions.
Do these microorganisms cause disease in the oral cavity or elsewhere?
Application to biotechnology
Bioengineering, biotechnologically relevant enzyme/compound production, drug targets,…
Summarise some of the most recent discoveries regarding this species.
1. Sahm, K., MacGregor, B.J., Jørgensen, B.B., and Stahl, D.A. (1999) Sulphate reduction and vertical distribution of sulphate-reducing bacteria quantified by rRNA slotblot hybridization in a coastal marine sediment. Environ Microbiol 1: 65-74.
This page is written by Amy Pham for the MICR3004 course, Semester 2, 2016