microbio "basics" Flashcards
(48 cards)
H. influenzae B
- Virulence factor
- vaccine component
- IgA protease- cleaves IgA
- **vaccine= anti PRP**
- capsule made of PRP = stop complement mediated phagocytosis capsule made of PRP
- (polyribosyltibitol phosphate) –> binds factor H in body which will prevent C3b depo onto host cell
clostridium perfringens
- toxin
- alpha toxin (exotoxin)
- lecithinase hydrolyzes lecithin in cell membranes –> cell lysis –> development of gas gangrene
- also causes hemolysis
Strep pyogenes (grp a strep)
- virulence factor
- toxin
- V FACTOR
- M protein (in bac cell wall)binds factor H tp prevent opsonization and destruction via the alternative complement pathway
- molecular mimicy of the M protein is what causes either rheumatic heart ds or glomerulnephritis
- TOXINs
- streptolysin O
- lyse cell membranes (along w streptolysin S will make S. pyogenes beta hemolytic
- ASO Ab are against streptolysin O
- erythrogenic exotoxin A+C =
- SUPERANTIGEN –> cause toxic shock-like syndrome
- streptolysin O
S. aureus
- virulence factor
- toxin
- virulence
- Protein A= in the cell wall, prevent opsonization by binding Fc region of Igs (turn upside down= can’t bind complement)
- exotoxin
- superantigen toxic shock syndrome toxin (TSST-1)= cross link MHCII –> activate so many T cells –> over production of IL-1, Il-2, IFN-y, TNF-alpa –> toxic shock syndrome
M. tuberculosis
- what mechanism of survival does it use?
trehalose dimycolate + cord factor
- cell wall component ,
- protect from Møs and instead stimulate granuloma formation
- after a few weeks of latent Mø infection, the Møs start expressing MHCII which will recruit CD4 and lead to granuloma formation)
- (CD4 cells will release IFN-y and better able phagocytosis against the TB)
- aka prevention of phagosome-lysosome fusion
bordatella pertussis
- toxin
- what factors wase pertussis invasion
- exotoxin= pertussis toxin
- inhibit phagocytic ability via disabling Gi –> inc cAMP in Nø –> unable to do oxidative burst
- also inhibit Møs
- ***sketchy= a disableed G.I. Joe**
- adhesins
- pertactin= allows adhesion to ciliated upper respiratory epithelium
- **military tactics**
cryptococcus neoformans
- what stains are used
- what protects it from the immune system
- stains
- ziehl neelson, mucicarmin, india ink
- **liam neeson, carmin, and indiana Jones walk into the crypt of neo-man**
- immune protection
- antiphagocytic polysacch capsule
enterococcus
- how can he grow? what stops him from growing?
- -gamma hemolysis (no do hemolysis)
- PYR + can grow in bile
- can grow in 6.5% NaCl- (will not appear on a urine nitrite bc cannot turn nitrate into nitrite)
strep pneumo
- virulence factor
- what else helps it resist the immune response
- IgA protease
- breakdown IgA
- resistance to phagocytosis via its thick polysacch capsule
shigella dysenteriae
- toxin (–> how does this manifest)
- shiga (exo)toxin= inhibit host protein synthesis
- bloody diarrhea = dysentery
- also will enahnce cytokine release and cause HUS (hemoyltic uremic syndrome = acute renal failure with hemolytic anemia)
corynebacterium
- toxin
- how will this manifest
- diptheria (exo)toxin=
- inactivate elongation factor 2 (EF-2) by adding ADP-ribose to it
- prevent protein elongation
- manifestation=
- sore throat (pharyngitis) + pseudomembrane on the back of the throat (dyptheria)
- lymphadenopathy = BULL NECK
listeria monocytogenes
- how you survive
- form “rocket tails”
- actin polymeriation that allows intracelular movement and cell-to-cell spread across cell membranes –> avoid Abs
- “tumbling mobility in broth”
bacillus anthracis
- toxin
** vikings around the cAMP fire, on water (bc edema) **
- edema toxin
- exotoxin that mimics cAMP in the GI tract –> inc Cle excretion –> inc fluid secretion –> watery diarrhea
- cutaneous anthrax= black eschar lesions on skin w characteristic edematous borders
- GI ulcers will also have the edema borders
- can also cause a necrotizing pneumonia with inc edema and
- forms spores that are resistant to high temperatures, chemical disinfectants, irradiation, and desiccation
- the only bacterium with a polypeptide capsule that keeps it safe
- medusa head appearance of colonies = halo of projections coming from the bac
clostridium : how they survive
toxins..
- C. tetani
- C. botulinum
- C. perfringens
- survivie
- forms spores that are resistant to high temperatures, chemical disinfectants, irradiation, and desiccation
- toxins
- C. tetani : tetanospasmin
- (the Joker): protease cleaves SNARE protein –> cannot bring pres-synaptic vescicle full of NTs to the membrane for fusion and dispersment into synapse
- inhibit GABA and glycine in renshaw cells of SC–> constant M activation –> rigid Ms ( spastic paralysis, risus sardonicus = the grin, lockjaw “trisumus” )
- C. botulinum
- botulnium exotoxin; protease cleaves SNARE protein –> cannot bring pres-synaptic vescicle full of NTs to the membrane for fusion and dispersment into synapse
- inhibit the release of Ach = no activation of post-synaptic membrane = FLACCID paralysis (“floppy baby”)
- C perfringens = alpha toxin
- exotoxin that will lyse the membrane via lecithinase =–> myonecrosis –> dec BF to the area = less O2 in env (necessary bc is an anaerobe) = gas gangrene and hemolysis = “double zone” of hemolysis on blood agar
- C. tetani : tetanospasmin
E. Coli
- anatomy that helps it invade
- toxin
- EHEC
- ETEC
*
- anatomy to get it: fimbriae/pilli for attaching to target cells K1 capsular Ag
- in strains that cause neonatal meningitis
- exotoxin
- EHEC : H for hemorrhagic diarrhea
- EHEC O157:H7 -Shiga-like toxin aka “verotoxin”: inhibit protein synthesis
- bind directly to 60S ribosome in bacteria and remove a very specfic adenosine –> inactive teh ribosome –> x protein synthesis
- bloody diarrhea (dysentery ) and will often cause HUS (acute renal failure with hemolytic anemia)
- ETEC: T for Temperature
- cause watery diarrhea via increased fluid secretion in the GI tract
- Heat Labile Toxin (LT) = does not survive hot temps
- increase cAMP in the GI tract –> Cl- + fluid secretion
- **labile in the air**
- Heat Stabile Toxin (ST)= survive hot temps aka fever
- inc cGMP –> block reabsorption of Cl- via NaCl transporter –> inc Cl- in the lumen and fluid secretion
- EHEC : H for hemorrhagic diarrhea
neisseria
- how does it get into the body
- virulence factor
- toxin
- fimbriae/ pilli for attaching to target cells
- virulence= IgA protease (breakdown IgA to evade immune response)
- endotoxin LSP for N. gonorrhea BUT LPO for N. meningitidis
vibrio cholerae
- how does it get into the body
- toxin
- fimbriae/ pilli for attaching to target cells
- toxin
- exotoxin= cholera toxin : cause fluid secretion via permaneny activation of Gs –> inc cAMP –> watery diarrhea
- = rice water diarrhea
- v serious: can cause death from dehydration and electrolyte abnormalities
which organisms use Lipid A as a virulence factor- what does it cause
Lipid A is the core of the endotoxin (O Ag is the end) found on select G(-) bacteria
- LPS= endotoxin = cause shock via 3 MOA
- bind CD14 on Møs –> inc IL-6 + IL-1 (fever) , TNF-alpha (fever and hypotension) + N.O synthesis (hypotension)
- actviates complement via incr _C3a (_histamine release) and C5a (nø chemotaxis)
- directly binds tissue factor –> coagulation cascade actvation –> DIC
lipid A unit in lipopolysaccharides is found in enteric bacteria it causes activation of macrophages –> widespread release of IL-1 and TNF-alph –> SEPTIC SHOCK
what different virulence factors are used by different strains of E. Coli- link the different virulence factors to the different clinical presentations

endotoxin vs exotoxin
- who has it
- method of release
- chemistry components
- location of genes
- potency
- gen MOAs
- gen clin presentation
- antigenicity
- vaccines
- heat stablity
- who has it
- ENDO: some G-, some G+
- EXO: only G- bc its in the cell membrane outler later and only G- have an outer layer
- method of release
- ENDO: secreted into circulation
- EXO: when bacteria dies, its membrane breaks apart and the LPS/LPO is released into circulation
- chemistry components
- ENDO: a protein (thus can be inactivated)
- EXO: Lipopolysaccharide LPS (Lipid A core, O Ag at the terminal end) **LPO in N. Meningitidis*
- location of genes
- ENDO: plasmid or bacteriophage (for some- the bacteriophage will insert some extra DNA into the bac DNA so they need the bacteriophage to give them te ability to make exotoxin)
- EXO: bacterial chr
- potency
- ENDO: HIGH (cause ds at low concentrations)
- EXO: LOW (need high concentrations to cause shock
- gen MOAs
- ENDO: 6 gen mechanisms
- inhibit protein synthesis (4)
- inc fluid secretion in GI tract (3)
- inhibit phagocytosis (bordatella)
- inhbit NT release (2)
- lyse the cell membrane (2)
- super Ag (2)
- EXO:
- CD14 activation of Møs –> inc IL-1+IL6, TNF-alpa, and inc NO synthesis
- activate complement C3a and C5s
- directly bind tissue factor –> set off coagulation cascade
- ENDO: 6 gen mechanisms
- gen clin presentation
- ENDO: not that sick, can be divided into categories of sx (dysentery, watery diarrhea, pharyngitis, toxic shock syndrome, NMSK block, skin changes)
- EXO: septic shock and meningococcemia (–> shock)
- antigenicity
- ENDO: yes, induce high titers of Abs (anti-toxins)
- EXO: poor (no Abs form)
- vaccines
- ENDO: can be made from toxoid = inactivated bacterial toxin protein
- i.e. TDaP vaccine : tetanus toxoid + diptheria toxoid + acellular pertussis
- EXO: no vaccines
- ENDO: can be made from toxoid = inactivated bacterial toxin protein
- heat stablity
- ENDO: mostly no (EXCEPT: staph superAg and ETEC ST)
- EXO: yes, it causes shock
- stable at 100 for up to an hour: febrile patients don’t kill off the endo toxin itself even if the back dies
who are the spore forming bacteria
- what is the function of spores
- how does this effect surgery
= bacillus (the rocket) + clostridium (system= destination)
- spores are released as a last ditch effort to keep the species alive : released by bacteria in very inhospitable environments (nutrients are limited)
- spores lack metabolic activity, and are highly resistant to heat and chemicals
- need to autcoalve to kill spores on surgical equipment by steeming at 121C for 15 min to kill them off to avoid inection
Bacillus anthracis (anthrax)
bacillus cereus (food poisening)
C. botulinum (botulism)
C. difficile (pseudomembranous colitis)
C. perfringens (gas gangrene)
C. tetani (tetanus)
which bacteria need a bacteriophage to bring them the genes for exotoxin production
- corneybacterium diptheria ***the big, classic one***
- Grp A strep (pyogenes)
- EHEC
- C. botulinism
- V. cholerae
NAME THAT BUG
G(-) bacteria
- exotoxin forming
- Cocci
- enteric bacilli
- zoonotic bacilli
- respiratory bacilli
G(-) bacteria
- exotoxin forming
- pseudomonas (exotoxin A)
- shigella (shiga toxin)
- EHEC (shiga like toxin)
- ETEC (shiga like toxin)
- Vibrio cholera (cholera toxin)
- bordetella pertussis (pertussis toxin)
- Cocci
- Neisseria (meningitidis and gonnorrea)
- enteric bacilli
- klebsiella
- enterobacters
- serratia
- salmonella (e + t)
- C. jejuni
- h. pylori
- proteus
- zoonotic bacilli (“-ella)
- bartonella henslae
- brucella
- francisella
- pasteurella
- respiratory bacilli
- H. influenzae
- legionella
which bugs do not gram stain well
(not G+ or G-)
the legion of superheros in hiding
-
mycoplasma and ureaplasma (Marvel Universe)
- no cell wall
-
treponema (the space station) and leptospira
- too thin to be seen
-
mycobacteria
- cell wall has high lipid content
- coxiella burnetti (the random brunette for love interest)
- Gardnerella vaginalis (poison ivy)
-
Legionella (the Legion)
- intracellular
-
Rickettsia (black widow)
- intracellular
-
chlamydia (captain america)
- intracellular
-
bartonella (barton - hawkeye)
- intracellular
-
anaplasma (ant man)
- intracelluar
-
Ehrlichia (the Mummy chant)
- intracellular
