Micro II-B – Flashcards
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| If a bacteriophage implants a toxic gene into a strep. pyogenes cell, what could occur |
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| scarlet fever |
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| extensive muscle and fat destruction along facial planes |
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| necrotizing fasciitis |
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| this bacteria avoids complement activity by being enclosed in a capsule |
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| Staph. Aureus |
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| this bacteria avoids complement activity by being coated with Protein A (IgA) |
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| Neisseria meningitidis (meningococci) Strep. Staph. |
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| This bacteria defends itself from complement activity by employing a peptidase to destroy C5a peptide |
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| Strep. Pyogenes (uses C5a peptidase) |
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| 2 bacteria that prevent the membrane attack complex from attaching to their surface due to their LPS |
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| Gram negatives like E.coli and Salmonella |
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| This bacteria produces an enzyme which lyses phagocytic cells |
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| Strep. Pyogenes -produces streptolysin |
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| When protein A binds to the wrong side of IgG antibody, what occurs? |
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| The Ab is unable to bind to the Fc receptor of phagocytes. So they are not recruited |
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| What bacteria synthesizes M-protein, and what is its effect |
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| Strep. Pyogenes Protein M binds serum-factor-H, which when bound degrades C3b, eliminating opsinization. |
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| This bacteria has a nearly endless array of pili and membrane proteins, which protects it from being targetted |
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| Neisseria gonorrhoeae |
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| The initiation of non-discriminate T-cell activation is caused by what? |
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| A super-antigen |
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| Generally speaking, a non-specific (excess) production of T-cells leads to what? |
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| Shock IL-2 cytokine released in excess which stimulated TNF-a production |
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| Genes encoding for virulence factors are often found ____ |
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| on plasmids and bacteriophages |
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| What makes a pathogenicity island |
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| Grouped virulence genes on a chromosome. The group of genes has distinct structural and functional units |
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| Tetracycline is an example of what kind of staining |
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| Intrinsic staining Mother was on drug during pregnancy |
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| Intrinsic stains are removable T/F |
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| False |
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| What is an example of extrinsic staining |
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| chlorohexidine, smoking, coffee |
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| A loosely attached collection of host cells and food debris, removed by air/water |
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| material alba |
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| highly structured accumulation of bacteria and their products, tightly attached |
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| dental plaque |
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| calcification of plaque over time results in |
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| calculus/tartar |
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| characteristics of plaque |
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| 1- acquired on teeth, restorations, oral cavity 2-composed of bacteria, their products, and host components 3- highly organized, orderly formation 4- composition varies b/w individual 5- variation in path of different types of plaque |
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| matrix-enclosed bacterial populations that adhere to eachother and/or surfaces.. |
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| bacterial biofilm |
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| when bacteria are suspended in a liquid, they are referred to as being |
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| in a planktonic state |
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| Bacteria living in a biofilm are resistant to host-defense mechanisms T/F |
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| True They exist as extracellular bact. protected by film... i.e. opsonization, IgA, complement, macrophages |
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| Bacteria in biofilm are relatively resistant to antibiotics T/F |
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| True, Protected within film to some extent |
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| Compared to the supragingival environment, the subgingival environment is |
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| lower O2 content lower CHO higher temperature |
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| What materials are transported through the "primitive circulatory system" of a biofilm |
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| Nutrients Waste Products (acids, etc.) |
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| What is metabolic cooperativity |
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| when different species provide for eachother in some way |
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| What is Quorum Sensing? |
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| communication b/w bacterial cells via small signalling molecules which will bind to receptors on other bact. |
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| What is the main communication of Quorum sensing? |
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| The overall density of the environment they live in (can affect growth rate of other cells) |
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| 3 steps in biofilm formation |
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| Attachment Growth Detachment |
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| What are some determinants of the microbial microenvironment? |
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| saliva GCF diet oral hygiene medical history ...many others |
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| What are some factors of bacteria that determine colonization? |
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| Adhesins Metabolic requirements Toxin production (can inhibit competitors) Coaggregation (cooperate with others) |
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| What makes up the acquired pellicle |
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| salivary proteins/glyco-proteins maybe some dead host/bact cells GCF food |
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| Prophy removes the acquired pellicle T/F |
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| True |
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| Components of the pellicle act as ___ whereas early colonizers act as _____ |
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| Receptors Ligands |
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| Initial Colonizers |
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| Strep. sanguis Strep. gordonii Strep. oralis Strep. mitis Actinomyces naeslundi |
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| Characteristics of early colonizers |
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| gram positive facultative anaerobes cocci and rods columnar colonies WELL tolerated |
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| Initial spread of proliferating cells occurs.. |
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| LATERALLY |
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| Organic components of extracellular matrix of plaque |
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| salivary/serum proteins and glycoproteins lipids bacterial polysaccharides |
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| Inorganic components of ECM of plaque |
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| iron (gcf/serum related)-SUB minerals (calcium, fluoride) |
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| As plaque develops, bacteria tend to become (Gram +/-) |
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| They become gram negative |
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| As plaque begins to mature, what can be said of the types of bacteria? |
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| more positive AND negative more rods and filaments anaerobic organisms |
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| Secondary/Late colonizers: |
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| Fusobacterium nucleatum Tannerellsa forsythenis Prevotella intermedia Porphyromonas gingivalis Treponema denticola Aggregatibacter actinomycetemcomitans |
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| Characterisitcs of late colonizers |
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| + and - facultative and obligate anaerobes cocci, branched rods, filaments, spiro. Associated with decay/gingival inflamm. |
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| At the climax of plaque maturation, what can happen to some bacteria? |
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| they can enter the planktonic state spread to other areas of oral cavity |
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| During development of subgingival plaque, what can be seen in the junctional epithelium |
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| presence of neutrophils |
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| The subgingival environment: |
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| low O2 high temp derived from GCF Increased protein metabolism |
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| Characteristics of subgingival plaque |
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| gram negative (LPS endotoxin!) anaerobic and capnophilic (CO2) proteolytic organisms (ptein metab.) associated with perio/gingivitis |
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| Examples of some things which can induce periodontal disease |
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| Plaque Drugs Smoking Cancer Fungus (candida albicans) |
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| A major difference between gingivitis and periodontal disease |
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| In PD: attachment apparatus affected |
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| Calculus is pathogenic T/F |
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| F only when plaque grows on calculus is it detrimental |
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| Cessation of oral hygiene leads to an increase in what morphologies of bacteria |
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| In order: cocci + rod filament spirochetes |
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| In regards to the gingivitis model, the amount of developing bacteria reaches a plateau T/F |
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| T Called the climax community |
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| Evidence in support of the specific plaque hypothesis |
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| -no direct correlation b/w amount of plaque and severity of disease -presence of certain morphotypes -association b/w specific species and a unique form of a disease |
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| Problems of applying Koch's to perio disease |
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| -difficult to isolate (complex mixture) -multiple forms of perio disease -a pathogen in one person might not be one in another individual -no animal model -does the org actually cause the disease, or just based on environment |
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| Sochransky's Modifications |
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| -pathogen should be at higher amount in affected individual (quantity) -removal of organism ceases disease -organism should posses virulence factors relevant to the disease -the host response should be directed towards the pathogen/bacteria |
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| Bacteria associated with Necrotizing Ulcerative Gingivitas |
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| Spirochetes Fusobacterium Selenomonas Prevotella intermedia |
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| A whitish pseudo-membrane on the papilla, induced by emotional stress could be: |
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| Necrotizing Ulcerative Gingivitis (trench mouth, Vincent's disease) |
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| A type of perio disease commonly found at the age of puberty, resulting in rapid bone loss of incisors and first molars |
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| Localized Aggressive Periodontitis |
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| The best association between perio disease and bacteria is: |
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Localized Aggressive Periodontitis and Aggregatibacter actinomycetecomitans (AA) |
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| Aggregatibacter actinomycetecomitans (AA) us characterized by: |
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| Gram negative coccbacillus (LPS) Capnophilic Secretes leukotoxin* Non-motile Non-encapsulated |
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| What is the effect of leukotoxin? |
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| Lysis or apoptosis of a host cell |
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| What specific toxin is capable of killing epithelial cells |
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| cytolethal distending toxin (CDT) |
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| Bacteria associated with Chronic Perio |
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| Porphyromonas gingivalis Tannerella forsythia AA Treponema denticola |
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| presence of subgingival calculus might indicate... |
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| chronic periodontitis |
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| Organisms which could inhibit growth of pathogenic bacteria: |
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| S. sanguis V. parvula C. orchracea |
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| Ecologic plaque hypothesis basics: |
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| In healthy individuals, pathogenic bugs at low levels based on the environment of oral cavity |
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| How do bacteria cause perio disease? |
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| Cause inflammatory responses TNF-a IL's PGE-2, pro-inflammatory molecules |
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| What bacteria is known for causing root caries |
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| Actinomyces viscosus |
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| What do caries-resistant hampsters lack? |
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| cariogenic bacteria |
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| Which bacteria have a strong association with most types of caries |
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| Mutans Streptococci (mutans, sobrinus, rattus, cricetus) |
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| Virulence of cariogenic bacteria |
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| rapid transport of fermentable CHO rapid conversion to produce acids produce CHO stores/resevoir Ability to maintain metab at low pH |
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| The ecological plaque hypothesis is relevant to: |
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| Perio disease and dental caries |
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| Broad grouping of fungi: |
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| Yeast and Molds |
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| Round/ellipsoid fungi, which multiply via mitotic budding |
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| Yeasts |
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| Fungi which are comprised of strands of multicellular filaments and branching tubules (hyphae) |
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| Molds |
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| During growth of fungi, a tangled mass of filaments is called |
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| mycelium |
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| Dimorphic fungi change their morphology based on what? |
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| Changes in temperature |
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| What are major virulence factors in fungi |
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| -being dimorphic (change based on temp) -melanin pigment -large CHO capsules |
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| An imperfect spore is one which... |
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| cannot mate |
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| What types of people might be more succeptible to fungal infections |
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| HIV Chemo patients Marrow/Organ transplant patients |
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| General virulence traits: |
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| detect host resist host evade host modify host steal nutrients from host |
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| Polyenes, azoles and allylamines are anti-fungal drugs which.. |
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| target and impair ergosterol synthesis in the cell membrane |
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| An infection which affects the hair shaft would be classified as: |
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| superficial |
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| a fungal infection affecting keratinized tissue is considered a: |
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| cutaneous infection |
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| Dermatophytes are: |
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| fungi restricted to the surface unable to survive above 37 degrees |
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| Subcutaneous fungal infections are generally caused by: |
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| geophilic fungi, entering skin through an injury |
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| neutropenia is classified as |
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| having low amounts of neutrophiles |
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| Budding asexual division by: Fragmented asexual division by: |
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| BLASTOconidia ARTHROconidia |
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| Lollipop structure |
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| Sporongiospore |
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| 4-8 spores in ascus sac |
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| Ascospore |
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| 4 spores in Basidium/club |
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| Basidospore |
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| a motile spore producing fungi |
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| Zoospore |
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| Drug which interrupts cell wall structure |
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| Echinocandins |
