13-pathogens and host defenses Flashcards
Name all virulence factors (5)
I ACE IT–adhesins, capsules, enzymes, invasins, injectisomes and translocon
What differs between adhesins and capsules
adhesins offer specific attachment; capsule are not specific, provide protection and can be found on non-virulent bacteria
How do we identify pathogens
set of virulence genes carried and express
Higher virulence–streptococcus pneumoniae or salmonella enterica serovar typhimurium
streptococcus pneumonaie
Name 7 extracellular enzymes
hyaluronidase, collagenase, lecithinase, hemolysin, leucocidin, protease, coagulase
Define virulence
ability to cause damage to host
Define pathogen
microorganism capable of causing disease
What determines site of colonization by pathogen?
adhesin type
Adhesin is specific to
A few cell type
Name 2 types of Adhesin & explain
Fimbriae/pili: polymer, long, loose attachment
Afimbrial adhesins: one protein, short, close attachement
Provide one example of afimbrial adhesin
HA protein
Which virus contains afrimbrial adhesin
influenza virus–HA protein
Capsules protects against
phagocytes
Name 2 bacterial pathgens w/ capsule as their essential virulence factors
streptococcus pneumoniae and haemophilus influenze
Name 2 ways to destroy host tissues
Penetration & release of extracellular enzyme
Name the protein in ECM holding cells to collagen mesh network
integrins
Describe the sequence of destruction of mucosa
Destruction of epithelial cells (single cell layer)–>invasion of loose connective tissue
Name two enzymes acting on ECM
Hyaluronidase and collagenase
Name 3 microorganism using hyaluronidase
staphylococci, streptococci, clostrida
What is the role of lecithinase (2)
lysis of red blood c
destroy tissue cell
Phosphatidylcholine in cell membrane is
a lecithinase
Provide an example of a lecithinase
phosphatidylcholine C
Name a strict anaerobe using hyaluronidase, collagenase, and hyaluronidase. Provide its common name
Clostridium perfringens/ gas gangrene
Cytolysins are what kind of enzymes. Elaborate
Hemolysins–lysis red blood cells and other types, enzyme or cytolysins (pore-forming)
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
- Complement system: proteins set–>pores in pathogen membrane & lysis
- Phagocytes
- 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
