Flashcards in Micro - Things IDK yet... Deck (190)
What is the red complex, and what bacteria does it include?
- related strikingly to clinical measures of periodontal disease
- particularly pocket depth & BOP
- includes Poryphormonas gingivalis, Tannarella forsythia, Treponema denticola.
What is the orange complex, and what bacteria does it include?
- also related to pocket depth
- this relationship & the relationship to other clinical parameters is less striking than the red complex
- includes P. intermedia, C. rectus, C. showae, E. nodatum, F. nucelatum, P. micros, P. nigrescens
* need orange complex for red complex to come in and flourish
What is a common trait of Red complex? And what does it do?
the expression of trypsin-like proteases; Trypsin-like proteases interact w/ host cell protease-activated receptor PAR-2
Pg gingipains have been shown to stimulate the secretion of cytokines via activation of...?
What pathogens share the ability to penetrate the gingival epithelium (invasive)? And why?
Aa, Pg, Tf, Td; due to their ability to produce toxic proteases (ex. endotoxins)
What bacteria are useful indicators of progressive periodontitis (in aggressive & chronic disease)?
Aa, Pg, Pi, Td, Tf
- one or more of these species occur in 99% of progressive lesions
- collectively, these species avoid/compromise host defenses and induce tissue dmg
what is one of the first stages of initiation of gingivitis?
bacterial exotoxins (i.e. Hyaluronidase) destroying intercellular connections betw epithelial cells lining the gingival sulcus.
Pg is commonly found in large numbers in gingivitis patients. Why is this?
WRONG! FALSE! NOOOOO! Pg is RARELY found in gingivitis patients and also remember, it is ABSENT from edentulous.
Gingipains are what and do what?
Gingipains are trypsin-like /cysteine proteases that degrade collagen, fibrinogen, fibronectin, complement components C3 & C5a, IgG & IgA.
*also have 2 arginine-specific and 1 lysine-specific
What does Arg-gingipain do?
It agglutinates and lyses the erythrocytes providing heme-a growth factor for Pg
What does gingipain cleave and what is the resulting consequence?
Gingipains cleave monocyte CD14, contributing to hyporesponsiveness to LPS and other bacterial triggers of mac activation.
______ and ______ promote adherence to host cells, contributing to the invasive capacity of Pg.
Pg fimbriae & Arg-gingipain
How does Pg persist in the plaque biofilm on tooth surfaces?
It attaches to Streptococcus gordonii via the major fimbrial subunit protein (FimA)
What is special about Pg's LPS?
It has hemin-dependent alteration in its structure of Lipid A that may reduce the host's ability to mount an innate immune response.
How is Aa invasive?
1. enter epithelial cells
2. escape phagocytic vacuoles
3. multiplies in cytoplasm
4. spread to adjacent epithelial cells via protrusions
How does Aa affect PMNs and mac's?
It produces a leukotoxin that can destroy PMNs and mac's by forming cation-selective pores that lead to the osmotic lysis of these cells.
What are the major Td virulence determinants?
2. Major outer sheath protein (Msp)
3. Sip protein
What is dentilisin?
a major Td virulence determinant that is a serine protease that degrades matrix prot & host cell junctional prot
- also activates host MMPs to degrade matrix
What is the Major outer sheath protein (Msp)?
a major Td virulence determinant that is a porin, causing membrane depolarization in some cells--cytotoxic to others
- alters fibroblast cytoskeleton reorganization, diminishing the cell migration, which prolongs tissue remodeling and wound healing
What is the Sip protein?
a major Td virulence determinant that induces arrest of T-cells in G1 and subsequent apoptosis, suppressing T-lymphocyte proliferation in response to mitogens (substances that induce mitosis)
In order for Td to be present, what else must be present?
Pg! They coaggregate not only w/ F. nucleatum but also with each other.
What is a major virulence determinant for Tannarella forsythia (Tf)?
BspA protein = binds to fibronectin & fibrinogen and stimulates neutrophil recruitment, inflammation, and bone resorption.
What type of patients would you find Prevotella intermedia (Pi)?
gingivitis, healthy, and edentulous patients
Pi expresses proteases and resists killing by phagocytes, but it lacks what...?
antiphagocytic capsule & collagenase production
Pi often dominates the subgingival flora in what type of gingivitis?
NUG = necrotizing ulcerative gingivitis
Predisposition to more severe chronic periodontitis occurs with...?
certain genetic polymorphisms (i.e. IL-1 genes)
What opportunistic pathogens/bacteria can infect a patient with a suppressed immune response due to periodontal disease?
cytomegalovirus, Epstein-Barr virus, and herpesvirus co-infections
Peripheral blood monocytes from PD pts release 2-3x more ...?
IL-1B (osteoclast activating factor)--this increase due to monocytes stimulated by LPS
What is wrong with treating oral infections w/ systemic antimicrobial agents? And why?
It risks side effects and gives varied results.
- Bc it is difficult to maintain adequate drug levels for a sufficient time at site of action
- Also bc of reduced susceptibility of bact in biofilm compared to planktonic bacteria on which AB MIC (minimum inhibitory conc) values determine