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- Colorado
- University of Colorado Health Sciences Center
- Microbiology, Immunology, And Molecular Genetics
- Microbiology, Immunology, And Molecular Genetics 5500
- Rabe
- Lecture 16: All Things Microbial & Dental
Lecture 16: All Things Microbial & Dental
Microbiology, Immunology, And Molecular Genetics 5500 with Rabe at University of Colorado Health Sciences Center
About this deck
By: Leah Keogan
Created: 2011-05-04
Size: 33 flashcards
Views: 32
Created: 2011-05-04
Size: 33 flashcards
Views: 32
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State the Gram status, O2 needs, shape, and role in the mouth of: Haemophilus.
Gram-negative facultatively anaerobic coccobacilli
o Normal flora in the mouth found in plaque biofilms, saliva and mucosa o Causes dentoalveolar infections, acute sialadenitis (salivary gland infection), infective endocarditis.
State the Gram status, O2 needs, shape, and role in the mouth of: Actinobacillus
Gram-negative microaerophilic or capnophilic (CO2 dependent) coccobacilli
- fimbria, many virulence factors - in perio pockets; implicate in aggressive Perio disease (localized & general) - copathogen w cervicofacial Actinomyces
State the Gram status, O2 needs, shape, and role in the mouth of: Eikenella.
Gram-negative facultatively anaerobic coccobacilli (formerly Bacteriodes)
- Plaque biofilms in both healthy & periodontitis ppl- Dentoalveolar abscesses, infective endocarditis; possibly implicated in some forms of chronic periodontitis.
State the Gram status, O2 needs, shape, and role in the mouth of: Capnocytophaga.
· carbon dioxide-dependent, Gram-negative rods
o Found in plaque, mucosal surfaces, saliva o Infections in immunocompromised, destructive periodontal disease o Some strains produce IgA protease.
State the Gram status, O2 needs, shape, and role in the mouth of: Porphyromonas gingivalis.
· Gram-negative anaerobic pleomorphic rods, non-motile; degrades collagen
o Can be normal flora or significant problem in PD o Gingival crevice and subgingival plaque in small no.s o Ass. w chronic periodontitis and dentoalveolar abscess.
State the Gram status, O2 needs, shape, and role in the mouth of: Prevotella.
Gram-negative pleomorphic anaerobic rods,
o May be part of normal flora. o Also found in periodontal pockets, dental plaque, chronic periodontitis and dentoalveolar abscess.
State the Gram status, O2 needs, and role in the mouth of: Fusobacterium.
Gram-negative anaerobic
- Can produce ammonia and hydrogen sulfide – “rotten egg”; odor causing in halitosis. - Normal gingival crevice and tonsils. - Also in periodontal infections, acute ulcerative gingivitis, dentoalveolar abscess.
What does P. gingivalis produce that makes it highly virulent? Other features that are bad? Where would we found it's relative: P. endodontalis?
o P. gingivalis is highly virulent in experimental infections, producing proteases, a haemolysin, collagen-degrading enzymes and cytotoxic metabolites; large capsule; fimbriae.
- P. endodontalis from infected root canals.
State the Gram status, O2 needs, and role in the mouth of: Leptotrichia
· Gram-negative filaments anaerobes.
o Found in dental plaque. No known disease association.
State the Gram status, O2 needs, shape, and role in the mouth of: Wolinella
· Gram-negative anaerobic bacilli.
o Found in the gingival crevice. Possible involvement in destructive periodontal disease.
State the Gram status, O2 needs, shape, and role in the mouth of: Selomonas
· Gram-negative anaerobic rods.
o Found in the gingival crevice. No known disease association.
State the Gram status, O2 needs, shape, and role in the mouth of: Treponema
· Motile Gram-negative anaerobic helical/spirillum.
o Difficult to culture. o Found in the gingival crevice; closely associated with acute ulcerative gingivitis, destructive periodontal disease (degrades collagen).
Which genus do the majority of the supragingival bacteria belong to?
Streptococci are the predominant supragingival bacteria; they belong to four main species groups: mutans, salivarius, anginosus and mitis
Which 5 species make up subgingival plaque?
The predominant cultivable species in subgingival plaque are Actinomyces, Prevotella, Porphyromonas, Fusobacterium, Veillonella.
How does saliva modulate bacterial growth? Provides/does...
- pellicle for bact adhesion (initially colonize w Streptococci) - a nutrient source - Clumping bact - non-specific (e.g. lysozyme (peptidoglycan), lactoferrin) & specific (IgA) defense - Maintain pH – buffers and Ca & Ph for remin.
What is the role of dextrans, glucans and fructans/levans in plaque? How are these molecules formed?
Bact hydrolyze sucrose and make polysaccharides like:
· dextrans make a sticky surface for other bugs · glucans – used by bacteria to store energy · fructans/levans – storage forms made by bugs – when broken down, plaque gets more acidic
How do bacteria stick to the surface of teeth?
MUST HAVE bact for PD and caries
- Bugs are NEGATIVELY charged, as is tooth surface
1. Ca+2 ions make a bridge between enamel and pellicle and bug 2. -bact use fimbriae, pili or flagella to bind to glycoproteins (salivary) of pellicle
What's the definition of a biofilm?
A biofilm is defined as a complex, functional community of one or more species of microbes, encased in an exopolysaccharide matrix and attached to one another or to a solid surface.
List the order of bacterial types that form plaque.
o Pioneers that selectively colonize the salivary pellicle during plaque formation are Gram-positive cocci and rods. (like Streptococci) o followed by Gram-negative cocci and rods. o Last by fusobacteria, spirillum and spirochetes.
What's the advantage to quorum-sensing molecules, secreted by biofilm bacteria?
·communication--> all act as one organism!
- Control genes related to extracellular polysaccharide production - Reduce metabolism (for bacteria at the bottom) - Control production of virulent factors, incl. drug-destroying genes.
What's the difference btwn sessile and planktonic organisms?
· live as aggregate (sessile organisms) vs free living organisms (planktonic)
· sessile orgs often drug resistant. Within a colony, the bact at the bottom of sessile group are shielded from any Abx (common on heart valve)
Plaque formation is essential for gingivitis and periodontitis; state why this is.
- Adsorption of host and bact to the tooth surface forms the acquired salivary pellicle.
What is the main etiological agent of periodontal disease?
The main etiological agent of periodontal disease is flora inhabiting subgingival plaque.
Describe the specific plaque hypothesis and give support. What does this hypothesis imply for treatment?
*key orgs cause disease*
o necrotizing ulcerative gingivitis caused by fusobact and spirochaetes. - Tx: Abx anti-anaerobes (metronidazole). o Actinobacillus actinomycetemcomitans in aggressive (juvenile) periodontitis, - Tx: tetracycline
Describe the non-specific plaque hypothesis and give support for it. What does this hypothesis imply for treatment?
disease caused by combo of non-specific orgs
- collective different bact groups have combo of virulence factors for tissue destruction
- implies plaque causes disease irrespective of its composition; many bact species in diseased perio pockets.
- implies plaque causes disease irrespective of its composition; many bact species in diseased perio pockets.
What do specific vs non-specific plaque hypotheses imply about PD therapy?
- non-specific: reduce the plaque to an acceptable level and the maintenance of healthy plaque, - specific: therapy should be directed at elimination of specific pathogens, for instance by appropriate antibiotic therapy
Describe the ecological plaque hypothesis for periodontal disease
- Host mounts inflammatory response to plaque--> increased GCF flow, which “feeds” Gram-neg anaerobes --> suppresses fac. anaerobic Gram + bact & pop. shift occurs in flora --> cyclical tissue destruction (from post-immune response)
Describe periodontal disease (PD) formation, in the context of the ecological plaque hypothesis.
- flora produce virulence factors that overwhelm host defenses --> tissue destruction/disease - PD is endogenous or opportunistic infxn, caused by imbalance in composition of the resident microflora due to alteration in the local ecology
What does the Ecology Hypothesis imply in terms of treating PD?
o Ecology hypothesis implies that periodontal disease may be treated by reducing the plaque to an acceptable level and the maintenance of healthy plaque. o Doxycylcine à Abx and anti-inflammatory; works well for this
Describe normal flora in the gingival sulcus
o Anaerobic, gram-positive bacilli are found in the range of 5%-14%
How does normal flora in gingival sulcus change during adult periodontitis?
- adult periodontitis: microflora changes from aerobic, non-motile, Gram + cocci to anaerobic, motile, Gram - bacilli
How does normal flora in gingival sulcus change during localized or generalized aggressive periodontitis?
o In localized or generalized aggressive periodontitis there is an increase in Actinobacillus either alone or synergistically with Capnocytophaga spp. and Porphyromonas gingivalis.
How does normal flora in gingival sulcus change during necrotizing ulcerative gingivitis?
o In necrotizing ulcerative gingivitis, Fusobacterium nucleatum and oral spirochetes (Treponema spp.) predominate.
About this deck
By: Leah Keogan
Created: 2011-05-04
Size: 33 flashcards
Views: 32
Created: 2011-05-04
Size: 33 flashcards
Views: 32
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy
Kathy