Virulence in bacteria Flashcards by Meleah McMillen

symbiosis that is beneficial to both organisms involved., relation is positive for both organisms

Mutualism

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is a class of relationships between two organisms where one organism benefits from the other without affecting it. Good for one, no problem for the other (most intestinal flora)

Commensalism

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non-mutual symbiotic relationship between species, where one species, the parasite, benefits at the expense of the other, the host. One takes advantage of the other

Parasitism

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Invasion and multiplication of micro-organisms

Infection

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Causes structural and functional damage

Disease

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E. Coli O157: H7 use this type of motility along with H-antigens, Listeria mnocytogenes (Not in all bacteria, mainly in gram - bacteria)

Flagella

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Flagella is composed of?

Flagellin

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Pili+fimbriae (which are the same thing) came together to be known as ?

Fibrillae

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Used mainly for adhesion by F-antigens

Pili

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Bacterial conjugation use this for plasmid transfer

Special pili known as sex pili

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parasites are capable of living and reproducing either inside or outside cells. ( cause Cell lysis)

Facultative intracellular

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cannot reproduce outside their host cell, meaning that the parasite’s reproduction is entirely reliant on intracellular resources. (cause Cell lysis)

Obligate intracellular

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Extracellular _________ -attach to the heart, parasites take over local use of nutrients oxygen

thrombosis

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Extracellular immunological reaction is when?

macrophages and neutrophils produce oxygen radicals/ enzymes to kill the host cell

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During invasion, what virulence factors are involved?

Capsule
need to haveProteins that circumvent innate immunity or they will be killed off
Iron uptake for growth (body hides iron from bacteria) bacteria have to counteract that to have iron for own metabolism
Production of extracellular enzyme like
a. Hyaluronidases
b. Collagenases
c. Fibrinolysins
d. Coagulases
e. Hemolysins
f. Leucocidins

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Not in all bacteria
composed of Polysaccarides-proteins
is a Virulence factor
a. colonization
b. invasion
c. Adhesion
d. Protection against phagocytosis and complement
Environmental protection (spore formation)
K antigens of the cell

Capsule

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Bacterial metabolites like Clostridium, high molecular weight–>vaccination (thus antigenic)

Type I, II, III

Exotoxins

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chemically treated (formalin) toxin

toxic effect goes down, antigenicity +vacination goes up

Anatoxins

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is the capacity of a chemical structure (either an antigen or Hapten) to bind specifically with a group of certain products that have adaptive immunity: T cell receptors or antibodies (a.k.a. B cell receptors).

Antigenicity

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Type of exotoxin that binds receptor, disturbance of cell metabolism.
Examples: STa ETEC, clostridium perfringens, Staphylococco, Streptococci

Type 1 exotoxin

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type of exotoxin where there is cell wall damage. staphylococcus aureus (alfa toxin-hemolysis), Actinobacillus pleuropneumoniae (pore forming)-makes holes in cell through cell lysis

Type II exotoxin

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Type of exotoxin that is intracellular toxins, A component goes intracellular (IC), B (binding) component binds membrane

Type III exotoxin

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Examples of Type III exotoxin

Heat labile toxin
Shiga toxin
Botulinum toxin
tetanospasmin

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Part of the cell wall in Gram +/- bacteria

Endotoxin (part of the cell wall)

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Toxin that targets cell wall components and causes lots of damage and causes an immune reaction. LPS (heat stable) Causes fever, general sickness, tissue damage, cardiovascular shock, death

Endotoxin for Gram negative

Function of the lipopolysaccharide?

Protection against toxic products and complement activation. Acts as an endotoxin for infections with a gram negative bacterium Endotoxin lipopolysaccharide is released by multiplication of membrane vesicles or they are released by "lysing" to get endotoxine release

Gram negative bacteria-->lipid A =Endotoxin----> ?

Endotoxic shock

Complement activation causes?

Anaphylatoxin Chemotaxis

Hageman factor causes?

Intravascular coagulation

Macrophages-------> ?

Cytokines

Cytokines------> ?

Different cells and organs

Different cells and organs-----> ?

Fever, general sickness, tissue damage, cardio shock

Toxins cell wall Gram + bacteria?

- Lipoteichoic Acid - Lipoarabinomannan (Myobacteria) - Peptidoglycan Fever, general sickness, tissue damage, cardiovascular shock, death

Actinobacteria are a type of?

Gram + bacteria

Secretion systems (not only for toxins) to Type 1-7 use?

Membrane vesicles (can export products from the cell), porin (goes to extracellular bacteria), injection system (needle like injects in host cell),

Spheric structure with a lipid membrane (part of an outer membrane) that con taints enzymes, exotoxins, dan(transformation), signal molecules

Membrane Vesicles

Role of membrane vesicles?

- Pathogenesis - Signaling (quoram sensing) - Excretion of toxic products - Killing of competitors - Immunomodulation - Excretion of bacterial toxic products - Transformation

What 3 places can the host cell membrane finds residence within?

1. Phagolysosomal vacuole 2. Unfused phagosome 3. Host cell cytosol

Bacteria in sessile form included. Gives bacterial persistence like in endocarditus, reduces host immunity, causes local damage, reduced susceptibility to antibiotics, find it within different surfaces

Biofilms

What are biofilms comprised of?

``` Polysaccharides Proteins Nucleic acids (DNA) ```

Role of lipoproteins-porins which are an outer membrane protein?

Pathogenesis Adhesion Iron uptake

Where does iron uptake take place (no free iron in the body)

Cell wall proteins

Iron uptake intracellular-epithelial cells use?

Ferritin

Iron uptake intracellular erythrocytes use?

Hemoglobin

Iron uptake intracellular muscular cells use?

Myoglobin

Serum: ?

transferrin

Mucosae: ?

lactoferrin

Infection with iron uptake...neutrophils----> ?

Lactoferrin

Pathogenic bacteria can circumvent iron restriction by this alternative for iron?

Manganese in Borrelia burgodorferi

Expression of iron uptake system under iron restrictive conditions?

- Siderophore receptor - Transferrine/lactoferrine receptor - Hemoglobine receptor

No complement activation (capsule)?

- presenceSialic acid on the surface | - enzymes that degrade the complement system

bacterium prevent from lysis by the host?

- Lipopolysaccharide | - Capsule

Inhibition of the complement mediated inflammation happens by?

Membrane vesicles (the complement expels to infect because they go all through vesicles-bacteria wait in vesicles to be activated by complement and then take up by white blood cell)

Cellular mechanism of innate immunity?

Phagocytes - Macrophages - Neutrophils NK cells

Virulence factors against phagocytes in extracellular bacteria?

-Capsule | Metabolites-exotoxins

Other Virulence factors against phagocytes?

- Biofilm (white blood cells can't penetrate) | - Facultative intracellular

Vaccines with living organisms

(attenuated)

DNA vaccines, vaccines based on antigens are vaccines without?

living organisms

Vaccines based on antigen?

Toxoid-inactivated exotoxin (isolated from bacterium or recombinant) Bacterins: inactivated complete bacterium Subunit vaccines with fimbriae, surface antigens (isolated from bacterium or recombinant)

Vaccines with living organisms are known as attenuated. These vaccines are not so frequent against bacteria?

-BCG vaccine -Bordetella bronchiseptica E.Coli

What type of immunity with vaccines with living organisms?

Both cellular and humoral immunity

Fast induction of protection?

Vaccines with living organisms (attenuated)

What are Vector vaccines and what do they use?

(Expression of immunogen epitome) they use attenuated salmonella

Genetic manipulation of attenuated vaccines include?

Serial passages in Vitro (Pasteur & rabies) Culture + mutagen Deletion mutants Vector vaccines

What type of vaccine is there generally a lot of antigen and frequently adjuvant added? - 2 administrations with 3-4 week intervals - Safe - Mainly production of antibodies

Vaccines based on antigen

What is included in the vaccine based on antigen known as Toxoid?

Exotoxin + formol Recombinant

What is included in the vaccine based on antigen known as Bacterins?

Complete bacterium Note:autovaccine Bacterium isolated from diseased animal and inactivation(formol) Care: side effects

What is included in the vaccine based on antigen known as Subunit?

Fimbriae (ETEC) | Iron capture systems; transferrin binding proteins (App)

Combination vaccines include?

Bacterin + toxoid Subunit + toxoid (ETEC Fimbriae and LT)