4. Periodontal Microbiology II Flashcards
Evaluation of Plaque Structure by Fluorescence in situ Hybridization and Spectral Imaging
Designed a set of fluorochrome-conjugated rRNA gene-specific oligonucleotide probes that targeted 96-98% of cells in healthy supragingival plaque.
* \_\_\_\_ * Use similar approach to what's done with 16S sequencing, and label probes with fluorochrome that bind to organisms in dental plaque * Listgarten's studie - corncob structures * And fpictures form this study, very similar type \_\_\_\_ form dental plaque in healthy individuals * Each different color represtns porbe they used for organisms - and bug in center of corncob structures - fusobacterium nucleatum, but they found pink organisms (\_\_\_\_) and not a lot of fusobacterium * Current thinking: maybe fusobacteirum is not as important as prveiously thought
biogeography
structure
cornyebacteria
Evaluation of Plaque Structure by Fluorescence in situ Hybridization and Spectral Imaging
“hedgehog structure”
* Develops structure of dental plaque based upon \_\_\_\_ * Further from tooth, closer to oxygen and carbs (decreasing \_\_\_\_) * Deep down, oxygen poor * And associate microenvironments with presence of bacteria * Cornccobs can form with \_\_\_\_ of different bacteria
hedgehog
gradient
multitude
“Suspected” Periodontal Pathogens: Culture-Independent Evaluation of the Oral Microbiome
With the advent of culture-____, ____ based methods of bacterial identification and ____, our understanding of the bacterial composition of the periodontal region has changed; it is far more ____ than previously thought.
At least ____ bacterial species are capable of colonizing the oral cavity and approximately ____ can simultaneously colonize an individual host.
In addition to the consensus red-complex ‘pathogens’ in chronic and severe periodontitis, newly recognized ____- cultivable organisms that increase in number in diseased sites include the ____ bacteria Filifactor alocis and Peptostreptococcus stomatis, and ____ species in the genera Prevotella, Megasphaera, Selenomonas, Desulfobulbus, Dialister and Synergistes.
independent
molecular
enumeration
diverse
700
150
non- or poorly-
gram-positive
gram-negative
“Suspected” Periodontal Pathogens in the Era of Culture-Independent Methodologies
The findings of such studies may necessitate a reassessment of the roles of certain species of bacteria in plaque formation, maintenance of health and progression to disease, amongst other issues.
The oral microbiome also includes numerous ____ and ____ (____) organisms that can influence the composition of its bacterial component.
* Fungal organisms and bacteriophages can modulate composition of oral microbiome * Would be great to remove individual bug without affecting the microflora and worrying about resistance; can utilize \_\_\_\_ therapeutically (they are v specific)
fungal
viral
bacteriophage
bacteriophage
The Ecologic Plaque Hypothesis
* Non-specific - wasn’t' important what was in plaque, just how \_\_\_\_ - not accurate * Specifc - partially accurate, not everything * Ecological - put clinical info into mcirobial ecology and udnerstanding effect of microenviornemtn on species * In peridontal heatlh with no inflamamtion, \_\_\_\_ GCF, oxygen is \_\_\_\_ > \_\_\_\_ anaerobes - periodotnal health * Accumulation of plaque - inflammation - drives down \_\_\_\_, affects \_\_\_\_ and shifts micrbiotia into \_\_\_\_ and \_\_\_\_ anaerobes that drives perioontitis
much
low
high
gram+
O2
GCF
gram-
obligate
Reinterpretation of the Ecologic Plaque Hypothesis
Review of Terminology
Keystone Pathogens – an organism with a ____ impact on the environment relative to its abundance in the overall community.
Commensals – microbes that can colonize hosts without causing ____ or tissue destruction.
Accessory Pathogens – commensal bacteria living in a particular niche that are not pathogenic by themselves but can enhance the ____ of other organisms.
Pathobionts – commensals that exhibit the potential to induce ____ under conditions of disrupted ____.
disproportionately large disease virulence pathology homeostasis
Reinterpretation of the Ecologic Plaque Hypothesis
Review of Terminology
Homeostasis – a condition of equilibrium or stability in a system, which is maintained by adjusting physiological processes to counteract external changes, e.g., a ____ between a host tissue and the resident microbiota in ways that prevent destructive inflammation or disease.
Symbiosis – close association of two ____ (e.g., a microbe and a mammalian host) that live together without necessarily implying that either partner benefits.
Dysbiosis – a situation resulting in an imbalanced microbiota that is associated with ____, e.g., ____ or ____ disease.
balanced relationship different species disease periodontitis inflammatory bowel
Reinterpretation of the Ecologic Plaque Hypothesis
[LOOK AT AMI’S NOTES]
Pathogenic Synergism
A situation in which individual microorganisms within a polymicrobial community that do not fulfill the requirements necessary to cause a ____, interact with other members of the community to collectively induce ____.
Polymicrobial Synergy and Dysbiosis Model
“Biofilm accumulation can invoke and deregulate a host ____ response, which will change the ____ microenvironment, which in turn can drive a ____ of the composition and activity of the microbiota, resulting in a more ____ host response, leading to further changes in the environment, and subsequently the ____ of communities of microorganisms that are even more suited to the prevailing conditions.”
disease
pathology
inflammatory subgingival reorganization aggressive selection
Reinterpretation of the Ecologic Plaque Hypothesis
Homeostasis - Periodontal Health
Dysbiosis Polymicrobial synergy; certain organisms cause disruption of ____ resulting in an ____ conducive to the growth of other
bacteria that trigger ____.
homeostasis
environment
inflammation
Reinterpretation of the Ecologic Plaque Hypothesis
* Inividinivudal with healthy periodntoiugm, bc of presence of early supragingival plaque, there is a \_\_\_\_ level of inflam reaction that occurs within the microenviornemnt (only seen \_\_\_\_) * This low level response - is sufficeinct to maintain peirodntoanl \_\_\_\_ * What changes - lapse in OH - accumultate supragingival - mature - onset of inflammation - resulting in \_\_\_\_ * Manifestations of gingival inflamamtion here may be in different individuals - under ifnlamamtion, enviornement produced that is conducive to \_\_\_\_ - and via events, there is in increase in levl of inlammation - facilitates deisease provoking inflammophilic population of organisms \_\_\_\_ - transition to periodontitis - now becomes circular, the \_\_\_\_ is extremely favorable for these organisms
low
histologically
homeostasis
gingivitis
keystones
subgingivally
environment
Current Concepts on the Bacterial Etiology of Periodontal Disease
Periodontal diseases are not bacterial infections in the classical sense; they are not caused by a single or a limited number of exogenous pathogens.
Periodontal disease is the result of a ____ community- induced perturbation of host homeostasis leading to inflammation in susceptible individuals.
Relevant organisms are likely a component of the ____ oral flora albeit in very low numbers at healthy sites and increasing in abundance at ____ sites.
Interactions between bacteria and both the ____ and ____ components of the host’s immune system are central to the pathogenesis of periodontal disease.
* We do periodontitis to ourselves, not AID, but it is a manifestation of host resopnse to bacteria presence * Bone resoprtion, brekadown of tissue - mediated by \_\_\_\_ mechanisms * Some \_\_\_\_ is important in formation of gingivitis
polymicrobial
normal
diseased
innate
adaptive
host
specificity
Current Concepts on the Bacterial Etiology of Periodontal Disease
Tissue damage can result via the direct effects of ____- derived substances that impact the viability of host cells and integrity of host tissues or indirectly, by induction of an ____ reaction on the part of the host.
Gingivitis results from a build-up in the ____ mass that is, in part, due to the accumulation of ____ bacteria leading to the induction of an ____ reaction that may be of a sufficient magnitude to ____ the biofilm.
Rather than there being distinct pathogens for any single form of periodontal disease, there appear to be complexes of organisms that synergize with one another to enhance colonization, persistence or virulence. Certain bacteria may be involved in the breakdown of ____ while others may trigger destructive ____ once homeostasis is disrupted. Collectively, they promote the onset of disease.
bacterially
inflammatory
plaque
gram-negative
inflammatory
“control”
homeostasis
inflammation
Current Concepts on the Bacterial Etiology of Periodontal Disease
Unique organisms may subvert and dysregulate the host immune system leading to changes in the microenvironment that drive a transition towards a pathogenic microflora (____).
The presence of certain organisms may be beneficial since they inhibit the growth of the more ____ species (S. sanguis, V. parvula and C. orchracea).
____ viruses may be involved in periodontal disease due to their ability to modulate certain elements of the ____ system. More ____ are needed to evaluate this concept.
Interactions between plaque ____ and ____ organisms may play a currently underappreciated role in the pathogenesis of periodontal disease.
dysbiosis
pathogenic
herpes
immune
studies
bacteria
fungal
Current Concepts on the Bacterial Etiology of Periodontal Disease
The story is far from complete as there are most likely relevant organisms (bacteria, viruses, bacteriophages and/or fungi) that have yet to be:
- fully characterized with respect to their ____, virulence factors or interactions with other microbes and the host,
- cultured,
- ____,
- or identified.
physiology
named
Intrinsic factors:
____
Epigenetic
____ microbiomes Systemic disease
Extrinsic factors: Environmental Acquired diseases \_\_\_\_ Nutrition \_\_\_\_ Stress
genetic
oral/systemic
medications
smoking
