Transcript The Microbiology of Bad Breath and Periodontitis

The Microbiology of Bad
Breath and Periodontitis
By Kate Egge
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Overview
• Background information about bad breath and
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Periodontitis
Discuss 3 bacteria that cause oral malodor
Methods for detecting bacteria and?or Bad breath:
PCR, organoleptic, VSC concentrations, and BANA tests
Research: that indicates bacteria cause bad breath
Research: that indicates that bacteria may cause
periodontitis
Conclusions
References
Questions
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Bad Breath
• Americans spent 625 million
dollars on breath fresheners in
2000.
• 85-95% of cases originate in
the mouth
• Microorganisms on the
posterior dorsal side of tongue
is the main source of bad
breath
• Area is poorly cleansed by
saliva and contains
invaginations where bacteria
can hide and putrefy postnasal
drip
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Periodontitis
• Some bad breath is associated with periodontal
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disease and destruction of gums
Periodontitis is a common, progressive disease
that affects the supporting structures of the
teeth, causing loss of attachment to the bone
and often resulting in tooth loss
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Bad breath
• Bad breath primarily result of
microbial metabolism.
• Organisms feed off of
glycoproteins and release
offensive chemical odors
• Oral gram-negative organisms
such as spirochetes and some
bacteroides have the capacity
to produce oral malodor
through putrification of sulfur
containing protein substrates
such as cysteine and
methionine
• Chemistry
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Important microorganisms
• Key anaerobic organisms Treponema
denticola, Porphyromonas gingivalis, and
Bacteroides forsythus
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Phylogenetic tree of major lineages
of Bacteria based on 16s ribosomal
RNA sequence comparisons
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Treptonema denticola
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Gram negative, anaerobic spirochete
A lot of size variation among the spirochetes
Form a major phylogenetic lineage of Bacteria
Protoplasmic cylinder
Flagella emerge from each pole and are located
in the periplasm of the cell (endoflagella)
Endoflagella and protoplasmic cylinder are
surrounded by a flexible membrane called the
outer sheath
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Porphyromonas gingivalis and
Bacteroides forsythus
• Member of genus Bacteroides
• Gram negative obligate anaerobe
• Ferments sugars to primarily acetate and
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succinate
Bacteroides species dominant bacteria in large
intestine, found 10^10 – 10^11 cells per gram
of human feces
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Porphyromonas gingivalis
• Several clinical studies show that P.
gingivalis is a factor in periodontitis
• Study Journal of Clinical Microbiology
compared the prevalence of P. gingivalis in
a group with periodontitis to a different
group that was periodontally healthy
• Results:
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Porphyromonas gingivalis
• P. gingivalis was detected in only 25% of
the healthy subjects but was detected in
79% of the periodontitis group
• The odds ratio for being infected with P.
gingivalis was 11.2 times greater in the
periodontits group than in the healthy
group.
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Porphyromonas gingivalis and PCR
• PCR assays were used for detection of
P.gingivalis
• Target sequence was the ribosomal DNA
spacer region between 16S and 23S
ribosomal genes
• DNA fragments were separated by
agarose gel electrophoresis
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Detecting Porphyromonas gingivalis
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Methods for detecting oral malodor
• Organoleptic measurements:
• Scale 0=no odor up to 5=foul odor
• Tongue malodor was assessed by scraping the
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posterior tongue dorsum with gauze and
immediately smelling it’s odor.
Malodor in dental sites was assessed by pushing
waxed dental floss between teeth and
immediately smelling and recording the odor
based on the organoleptic scale
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Methods for detecting oral malodor
continued…
• High VSC concentrations indicate oral malodor
• Volatile Sulfur Compounds (VSC) are measured with a
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portable sulfide monitor
VSC monitor contains a pump which sucks air from a
plastic straw placed inside the subjects mouth
The mouth air is passed through an electrolytic sensor
which measures the concentration of volatile sulfurs
VSC levels are strongly associated with organoleptic
scores
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Methods for detecting oral malodor
continued
• BANA test
Test kit for bacterial trypsin like activity based on the
hydrolysis of benzoyl-DL-arginine-naphthylamide (BANA)
used to asses the presence of one or more of
T. denticola , P. gingivalis , B. forsythus
• These bacteria are capable of hydrolyzing the synthetic
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trypsin substrate BANA- an activity not identified in other
oral microbial species
Conditions favoring a Positive BANA test on the tongue
dorsum and tooth sites were associated with oral
malodor production
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Relationship of Oral Malodor to
Periodontitis
• Species identified by BANA tests have been
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tentatively implicated as putative periodontal
pathogens
However, some studies have found that species
Treponema denticola, Porphyromonas gingivalis,
and Bacteroides forsythus identified by BANA
tests do not cause periodontitis.
When peridontitis was present 87.5% of tooth
sites and 92.5% of tongue sites were BANA (+)
In healthy individuals 74.4% of tooth sites and
93% of tongue sites were BANA (+)
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Relationship of Oral Malodor to
Periodontitis continued
• Oral malodor is not directly associated
with presence of periodontitis
• Substantial oral malodor may be present
in individuals without periodontitis
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Conclusions
• Gram negative anaerobic oral bacteria (Treponema denticola,
Porphyromonas gingivalis, and Bacteroides forsythus ) cause bad
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breath
Key anaerobic organisms Treponema denticola, Porphyromonas
gingivalis, and Bacteroides forsythus degrade glycoproteins proteins
and release foul smelling chemicals
Strong evidence indicates that these bacteria cause bad breath
Treponema denticola: Anaerobic spirochete, Protoplasmic cylinder
and endoflagella
Porphyromonas gingivalis, and Bacteroides forsythus are both
members of the genus Bacteroides
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Conclusions continued
• Bacteria on the posterior dorsal side of tongue is the
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main source of bad breath
One study using PCR found that P.gingivalis was 11x
more likely to be found in individuals that had
periodontitis- P. gingivalis may be a periodontal
pathogen
However, research using BANA tests found that the
presence of T. denticola, P. gingivalis, and B. forsythus
was NOT associated with periodontitis
• Oral malodor is not directly associated with the presence
of periodontitis
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References:
• Rosenberg, Mel. Clinical Assessment of Bad Breath: Current Concepts.
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Journal of the American Dental Association 1996; 127: 475-82
Griffen A, Becker M, Lyons S. Prevalence of Porphyromonas gingivalis and
Periodontal Health Status. Journal of Clinical Microbiology 1998; 36(11)
:3239-42
Madigan M, Martinko J, Parker J. Biology of Microorganisms. Ninth edition
A, Bosy, G.V. Kulkarni, M. Rosenberg and C.A.G. McCulloch. Relationship of
oral malodor to periodontitis: Evidence of independence in discrete
subpopulations. Journal of Periodontology 1994; 65:37-46.
Rosenberg Mel. The science of Bad Breath. Scientific American 2002; 72-79.
Bruce P,Boches S, Galvin J. Bacterial Diversity in human subgingival plaque.
Journal of Bacteriology 2001;183(12): 3770-83.
De Boever E, Uzeda M, Loesche W. Relationship between volatile sulfur
compounds,Bana-Hydrolyzing bacteria and gingival health in patients with
and without complaints of oral malodor. Journal of Clinical Dentistry 1994;
4(4):114-119
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