chapter 2: cell structures, virulence factors and toxins Flashcards
the flagellum is affixed to the bacteria by the ___ ____ which spins around to move the flagellum
basal body
vibrio cholera has how many flagella
single
e coli flagella
also proteus mirabilis
many around the cell
shigella has ___ flagella
no
____ can serve as adherence factors called ___
and these are necessary for certain bacteria to cause virulence
pili
adhesins
which bacteria is unique in that its capsule is made up of amino acid residues
bacillus anthracis
what are capsules
protective walls that surround the cell membrane of bacteria
-usually made of simple sugar residues
how do capsules make bacteria more virulent
macrophages and neutorphils cannot phagocytize encapsulated bugs
what 2 tests enable doctors to visualize capsules under the microscope and aid in IDing bacteria
first one IDs what bacteria
india ink stain: appears as tranparent halo around cell
-identify cryptococcus
(halo around the crypt)
quellung reaction: bacteria mixed with Abs that bind capsule, when bind, capsule swells with water and this is visualized
how does our body get rid of encapsulated bacteria
Abs bind it, opsoninzing it which helps macrophages and neutrophils
endospores have a multilayered protective coat consisting of
cell membarne thick peptigoglycan mesh another cell membrane wall of keratin like protein outer layer called exosporium
biofilms fnct
allows bacteria to bind to prostetic devices like IV catheters
protects them from attack by antibiotics and immune system
whch bacteria forms biofilms on intravascular catheters and can cause catheter related sepsis
staphlyococcus epidermidis
facultative intracellular organisms
bacteria that get phagocytosed by macrophages and neutrophils but survive unharmed
-prevent phagosome-lysosome fusion
facultative intracellular organisms
listen sally yer friend bruce must leave now
listeria, salmonella, yersinia francisella brucella legionella mycobacterium nocardia
exotoxins are mainly secreted by what but certain gram ___ bacteria like ___ and ___ secrete them too
gram positive
gram negative like virbio cholera and E. Coli
neurotoxins and examples
exotoxins that act on nerves or motor endplates that cause paralysis
tetanus toxin
botulinium toxin
enterotoxin
exotoxins that act on GI tract to cause diarrhea
-inhibit NaCl absorption and cause its secretion
enterotoxins cause 2 disease manifestations
examples
infectious diarrhea:
- V cholera, E coli, campylocbater jejuni, shigella dysenteriae
food poisoning:
bacillus cereus
staphylococcus aureus
pyrogenic exotoxins stimulate release of ___ and can cause
examples
cytokines
can casue rash, fever, toxic shock
staphylococcus aureus
streptococcus pyogenes
exotoxin subunits
2 polypeptide subunits bound together by disulfide bridges
B or H binds to target cell
A or L exerts toxic effect
what is bacteremia
bacteria in the blood stream
4 bacteria that produce exotoxins that increase levels of cAMP
cholera
anthrax
montezumas revenege (E coli)
pertussis
cAMP
