13-pathogens and host defenses Flashcards by SUN Z

Name all virulence factors (5)

I ACE IT–adhesins, capsules, enzymes, invasins, injectisomes and translocon

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What differs between adhesins and capsules

adhesins offer specific attachment; capsule are not specific, provide protection and can be found on non-virulent bacteria

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How do we identify pathogens

set of virulence genes carried and express

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Higher virulence–streptococcus pneumoniae or salmonella enterica serovar typhimurium

streptococcus pneumonaie

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Name 7 extracellular enzymes

hyaluronidase, collagenase, lecithinase, hemolysin, leucocidin, protease, coagulase

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Define virulence

ability to cause damage to host

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Define pathogen

microorganism capable of causing disease

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What determines site of colonization by pathogen?

adhesin type

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Adhesin is specific to

A few cell type

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Name 2 types of Adhesin & explain

Fimbriae/pili: polymer, long, loose attachment

Afimbrial adhesins: one protein, short, close attachement

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Provide one example of afimbrial adhesin

HA protein

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Which virus contains afrimbrial adhesin

influenza virus–HA protein

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Capsules protects against

phagocytes

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Name 2 bacterial pathgens w/ capsule as their essential virulence factors

streptococcus pneumoniae and haemophilus influenze

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Name 2 ways to destroy host tissues

Penetration & release of extracellular enzyme

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Name the protein in ECM holding cells to collagen mesh network

integrins

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Describe the sequence of destruction of mucosa

Destruction of epithelial cells (single cell layer)–>invasion of loose connective tissue

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Name two enzymes acting on ECM

Hyaluronidase and collagenase

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Name 3 microorganism using hyaluronidase

staphylococci, streptococci, clostrida

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What is the role of lecithinase (2)

lysis of red blood c

destroy tissue cell

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Phosphatidylcholine in cell membrane is

a lecithinase

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Provide an example of a lecithinase

phosphatidylcholine C

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Name a strict anaerobe using hyaluronidase, collagenase, and hyaluronidase. Provide its common name

Clostridium perfringens/ gas gangrene

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Cytolysins are what kind of enzymes. Elaborate

Hemolysins–lysis red blood cells and other types, enzyme or cytolysins (pore-forming)

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Which two types of extracellular enzymes induce lysis of red blood cells

Hemolysins and lecithinase

Leucocidin induces

lysis of leucocytes

Name 2 bacteria using leucocidin

staphylococci, streptococci

Bateria using leucocidin as more likely to be gram

Gram negative

Which enzymes degrade complement protein and antibodies

proteases

Coagulases are produced by

virulent staphylococci

Staphylococci use (3 enzymes)

hyaluronidase, coagulases, leucocidin

What is the role of coagulases

use fribrin to cloak bacteria from host's immune system

Invasins are what type of proteins

surface or injected

What is a major virulence factor for entracellular pathogens triggering endocytosiss

invasin

Which type of virulence factor can invade cells as well as phagocytes

invasins

What are the benefit of invasins for the bacteria

invasins invade host cell and phagocytes: | source of nutrient & protection against immune syst of host

Name 4 microorganism using invasin

myobacterium, salmonella, listeria, chlamydia

What type of virulence factors form channels

injectisomes and translocons

Injectisomes form channels through to (4 membranes)

cytoplasmic/vacuolar membrane, periplasm, outer membrane+peptidoglycan layer, cytosolic cell membrane

The ultimate goal of injectisome

inject effectors into cytol of host

Gram___bacteria use injectisome

Gram negative

Gram negative bacteria use (2)

leucidin and injectisome

Name 3 functions of effectors

Invasion of host cell Block phagosome maturation Take control of host cell

Name two types of toxigenicity induced by bacterial pathogens

Infectious disease (growth) and Intoxication

Name 3 types of infectious disease

pneumonia, meningitis, syphilis

Name one major virulence factor for staphylococci pneumonae

capsule

Name one major virulence factor for haemophilus influenza

capsule

Name 5 characteristics of exotoxins

``` 1-heat-labile proteins 2-soluble 3-potent 4-AB toxin 5-categorized by target ```

What modifies host cells from within?

AB toxin

Name the functions of A, B subunits

A-modify target inside host | B-specific binding

Name one type of A-subunit toxin

ADP-ribosyltransferase modifying host protein

Name 3 types of AB-toxins; they are produced by

1-Botulinum toxin-clostridium botulinum 2-Tetanus toxin-clostridium tetanii 3-Diphteria toxin-corynebacterium dipheteria

What is the vaccine for dipheteria toxin

DTaP

Botox causes sweating

hyperhydrosis

Which toxins is found in bacteria living in soil forming spores

Clostridium tetanii

Differentiate the mode of inhibition btwen botulinum and tetanus toxin

1-botulinum: flaccid paralysis, inhibit release of Ach -->inhibit muscle contraction 2-tetanus: spastic parylysis; inhibit glycine release-->prolonged release of Ach-->prolonged contraction

Name a AB5 toxin; bateria

Cholera toxin; vibrio cholerae

Describe the mode of action of cholera & Sx

subunit B binds to receptor GM1 on intestinal epithelial cell Subunit A: take ATP-->cAMP( control Na transport)--->accumulation cAMP--> stop Na transport into the cell-->Cl and HCO3 release outisde in the lumen-->accumulation of fluid in lumen-->massive water loss & diarrhea

Endotoxin are released by Gram___bacteria

Gram negative

Which type of toxin have systemic effect; describe

endotoxin; pyrogenic fever, weakness, inflammation, diarrhea, septic shock

Name 5 characteristics of endotoxins

``` 1-Heat stable 2-Lipid A of LPS-->gram neg 3-weakly immunogenic 4-release during multiplication or lysis of bacterial cell 5-systemic effect ```

What is the diff btwn innate and adaptive defenses.

- Innate: properties of normal host, non-specific | - Adaptive: induced by infection; specific to the pathogen based on ANTIGENS

What the 1st barriers

skin and mucous membrane

Normal microbbiome of the skin and mucous membrane

Competes for attachment sites and nutrients | Secretes BACTERIOCIN

Bacteriocin is

secreted by the normal microbbiome

Antimicrobial substances include

FA, lysoymes, antimicrobial peptides (AMPs), antibodies (if the host if immune)

Antibodies are secreted when the host is

immune

Skin is

a thick layer of dead cells

Mucous membrane produce

mucus

AMPs is the shortcut for and its role is

antimicrobial peptides; make pores in the bacterial membrane

Describe innate defenses components of the airways (2)

mucous membrane, mucus (traps bacteria); ciliated cells (removes mucus & bact up the trachea & dump into oesophagus)

What happens when bacteria overcomes the first line of defenses (skin and mucosa)?

It encounters a second line of defenses

Name the component of the second line of defenses (3) of tissues/ internal fluids

1. Complement system: proteins set-->pores in pathogen membrane & lysis 2. Phagocytes 3. Inflammation: general nonspecific response of innate syst to toxins and pathogens

Imflammation is speci or non-specific?

Non specific

Complement syst consists of proteins (name them)

C1-c9

Complement system complement the action of

Antibodies

Activation of the complement system is by 2 pathways:

1-classical pathway through antibodies | 2-Alternative pathway: microbial cell wall components (polysaccharides, lipopolysaccharide)

MAC results from

Activation of the complement system --> Membrane attack complex (MAC) -->lysis of gram-negative

MAC has no effect on

Gram-positives

Serum sensitivty

test sensitivity to complement by exposing pathogens to serum (blood w/out RBC)

What is serum

blood w/out RBC