Virulence in bacteria Flashcards
symbiosis that is beneficial to both organisms involved., relation is positive for both organisms
Mutualism
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
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
Invasion and multiplication of micro-organisms
Infection
Causes structural and functional damage
Disease
E. Coli O157: H7 use this type of motility along with H-antigens, Listeria mnocytogenes (Not in all bacteria, mainly in gram - bacteria)
Flagella
Flagella is composed of?
Flagellin
Pili+fimbriae (which are the same thing) came together to be known as ?
Fibrillae
Used mainly for adhesion by F-antigens
Pili
Bacterial conjugation use this for plasmid transfer
Special pili known as sex pili
parasites are capable of living and reproducing either inside or outside cells. ( cause Cell lysis)
Facultative intracellular
cannot reproduce outside their host cell, meaning that the parasite’s reproduction is entirely reliant on intracellular resources. (cause Cell lysis)
Obligate intracellular
Extracellular _________ -attach to the heart, parasites take over local use of nutrients oxygen
thrombosis
Extracellular immunological reaction is when?
macrophages and neutrophils produce oxygen radicals/ enzymes to kill the host cell
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
- 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
Bacterial metabolites like Clostridium, high molecular weight–>vaccination (thus antigenic)
Type I, II, III
Exotoxins
chemically treated (formalin) toxin
toxic effect goes down, antigenicity +vacination goes up
Anatoxins
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
Type of exotoxin that binds receptor, disturbance of cell metabolism.
Examples: STa ETEC, clostridium perfringens, Staphylococco, Streptococci
Type 1 exotoxin
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
Type of exotoxin that is intracellular toxins, A component goes intracellular (IC), B (binding) component binds membrane
Type III exotoxin
Examples of Type III exotoxin
- Heat labile toxin
- Shiga toxin
- Botulinum toxin
- tetanospasmin
Part of the cell wall in Gram +/- bacteria
Endotoxin (part of the cell wall)
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?
- Phagolysosomal vacuole
- Unfused phagosome
- 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)
