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Bacteria Associated with Periodontal Disease. 23 June 2008 Article Presentation BBSI Summer 2008. Annica Stull-Lane. VCU Mentor: Kimberly Jefferson. Diaz PI, Zilm PS, Rogers AH. (2002) Microbiol 148 : 467-472. How do bacteria cause disease?. ?. !. DISEASE.
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Bacteria Associated with Periodontal Disease 23 June 2008 Article Presentation BBSI Summer 2008 Annica Stull-Lane VCU Mentor: Kimberly Jefferson Diaz PI, Zilm PS, Rogers AH. (2002) Microbiol 148: 467-472
How do bacteria cause disease? ? ! DISEASE http://www.ou.edu/class/pheidole/bacteria.html
What causes periodontal disease? • Periodontal disease: healthy gums gingivitis periodontitis http://www.enexus.com/gumdisease/ • Well, associated with many bacteria, including…
BACTERIA! • Strictly anaerobic • Found in oral cavity Porphyromonas gingivalis Fusobacterium nucleatum WAIT! http://www.pgingivalis.org/photo_gallery.htm http://www.ronaldschulte.nl/Preparaten%20Tandplaque%2002.htm
Experimental Question • Diaz PI, Zilm PS, Rogers AH. (2002) Microbiol 148: 467-472 • Background: Bradshaw et al. (1998) suggested F. nucleatum as a “bridge” or “mediator” of co-aggregation • Diaz et al. ask: Can F. nucleatum by itself protect P. gingivalis (and perhaps other anaerobes less tolerant to oxygen)?
Overview of Experiments • Test oxygen tolerance of monocultures and a co-culture • Test carbon dioxide requirement of monocultures and co-culture P. gingivalis Co-culture Monocultures Chemostat F. nucleatum
Co-culture Experiment • cell viability measured by viable counts 0 % O2 10 % O2 20 % O2 5 % CO2 0 % CO2
Results: Monocultures • Oxygen tolerance • P. gingivalis: doesn’t survive at 10% O2 or 20% O2 , but does at 3% and 6% O2 • F. nucleatum survives at even higher O2 concentrations than air (21-ish% O2)
Results: Monocultures • CO2 requirement P. gingivalis F. nucleatum
Results: Co-culture • In the presence of F. nucleatum, With CO2 P. gingivalis survived in all oxygen concentrations! Without CO2 P. gingivalis survived w/o CO2 in all O2concentrations!
Results: Co-culture • At the higher O2 level (20%): 0% O2 20% O2 A biofilm formed, w/ P. gingivalis F. nucleatum cells lengthened
So how do these anaerobic bacteria survive? • This study suggests: • F. nucleatum creates a necessary reduced O2 condition and a supply of CO2 for survival of P. gingivalis • O2 tolerances, oxidative stress and biofilm, CO2 requirements and co-culture • Plaque biofilm gives insight into relationships among pathogenic bacteria
Etiology of periodontal diseases • Important: determining how microorganisms survive during different stages of plaque development • Control of particular species might drastically affect the pathogenic ecosystem periodontal DISEASE
Diaz PI, Zilm PS, Rogers AH. Fusobacterium nucleatum supports the growth of Porphyromonas gingivalis in oxygenated and carbon-dioxide-depleted environments (2002) Microbiol 148: 467-472