Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
84 Cards in this Set
- Front
- Back
|
(T/F) The outer membrane for G+ and the cell membrane for G- act as major surface antigens.
|
FALSE: they DO act a major surface antigens BUT the outer mb
for G- and the cell membrane for G+ |
|
|
2. Are endotoxins heat stable?
|
yes, stable at 100C for 1 hr.
|
|
|
3. Are endotoxins secreted from cells?
|
No
|
|
|
4. Are endotoxins used as antigens in vaccines?
|
No they don't produce protective immune response
|
|
|
5. Are exotoxins heat stable?
|
no, destroyed rapidly at 60C (exception: Staphylococcal enterotoxin)
|
|
|
6. Are exotoxins secreted from cells?
|
Yes
|
|
|
7. Are exotoxins used as antigens in vaccines?
|
Yes, TOXOIDS are used as vaccines
|
|
|
14. Does endotoxin induce and antigenic response?
|
no, not well
|
|
|
15. Does exotoxin induce and antigenic response?
|
Yes, induces high-titer antibodies called antitoxins
|
|
|
18. How are the pathogenic Neisseria species differentiated?
|
on the basis of sugar fermentation Maltose
|
|
|
19. How are the species of Streptococcus primarily differentiated?
|
on the basis of their HEMOLYTIC capabilities & Lancefield Ag
|
|
|
20. List the four phases of the bacterial growth curve.
|
Lag phase - log (exponential) phase - stationary phase - death phase
|
|
|
23. Name 2 bacteria that use IgA protease to colonize mucosal surfaces.
|
S. pneumoniae & Neisseria
|
|
|
22. Name 2 G- rods which are lactose nonfermenters and Oxidase(-)?
|
Shigella, Salmonella
|
|
|
25. Name four genus of bacteria that are G+ rods.
|
1) Clostridium (an anaerobe) 2) Coynebacterium 3) Listeria 4) Bacillus
|
|
|
27. Name three diseases caused by exotoxins.
|
Tetanus - botulism – diptheria
|
|
|
28. Name 2 G- bacteria species that make exotoxins.
|
E coli
Vibrio Cholera |
|
|
Teichoic acid induces what two cytokines?
|
TNF and IL-1
|
|
|
What are the effects of erythrogenic toxin?
|
it is a superantigen - it causes rash of Scarlet fever
|
|
|
What are the effects of streptolysin O?
|
it is a hemolysin - it is the antigen for ASO-antibody found in rheumatic fever
|
|
|
What are the effects of the exotoxin secreted by Bacillus anthracis? (1)
|
edema
|
|
|
What are the effects of the exotoxin secreted by Clostridium botulinum?
|
blocks release of acetylcholine: causes anticholenergic
symptoms, CNS "flaccid" paralysis; baby seen as failing to thrive |
|
|
What are the effects of the exotoxin secreted by Clostridium perfringens?
|
alpha toxin is a lecithinase - causes gas gangrene - get a double zone of hemolysis on blood agar
|
|
|
What are the effects of the exotoxin secreted by Clostridium tetani?
|
blocks release of the inhibitory NT glycine; causes 'lockjaw'
|
|
|
What are the effects of the exotoxin secreted by Corynebacterium diphtheria? (3)
|
1) inactivates EF-2 by ADP ribosylation 2) attack heart 3)'pseudomembrane' in throat
|
|
|
What are the effects of the exotoxin secreted by Staph. aureus?
|
superantigen; induces IL-1 and IL-2 synthesis in Toxic Shock Syndrome; also causes food poisoning
|
|
|
What are the effects of the exotoxin secreted by Vibro cholerae? (3)
|
Stimulates adenylate cyclase by ADP ribosylation of G protein - increases pumping of Cl- and H2O into gut - causes voluminous rice-water diarrhea
|
|
|
What are the general clinical effects of endotoxin?(2)
|
fever, shock
|
|
|
What are two exotoxins secreted by Strep. pyogenes?
|
Erythrogenic toxin and streptolysin O
|
|
|
What are two species of Gram (-) cocci and how are they differentiated?
|
1) Neisseria memingitidis: maltose fermenter 2) Neisseria gonorrhoeae: maltose NONfementer
|
|
|
What culture requirements do Lactose-fermenting enterics have?
|
MacConkey's agar (make pink colonies)
|
|
|
What culture requirements does C. diphtheriae have?
|
Tellurite agar
|
|
|
What culture requirements does N. gonorrhea have?
|
Thayer-Martin (VCN) media
|
|
|
What is the chemical composition of endotoxin?
|
LPS
|
|
|
What is the major function of the capsule?
|
antiphagocytic
|
|
|
What is the function of a glycocalix?
|
mediates adherence to surfaces, especially foreign surfaces (i.e. catheters)
|
|
|
What is the primary test to subcatergorize G- rods?
|
are they Lactose Fermenters?
|
|
|
What is the unique chemical component of Gram + cell membranes?
|
Teichoic acid
|
|
|
What test distinguishes Staph. and Strep?
|
Staph. are Catalase (+) and are in clusters - Strep. are Catalase (-) and are in chains
|
|
|
Where are the spores of Clostridium botulinum found?
|
canned food - honey
|
|
|
Which has a higher toxicity: exotoxin or endotoxin?
|
EXOTOXIN: fatal dose is ~1ug! (for endotoxin, fatal dose is hundreds of micrograms)
|
|
|
Following primary infection with TB, under what conditions would the lesion likely progress to lung disease?
|
HIV, malnutrition. This progressive lung disease can rarely lead to death.
|
|
|
How are Mycobacteria visualized in the lab?
|
acid-fast stain =Ziehl-Neelson
|
|
|
How is Shigella spread?
|
food, fingers, feces, and flies'
|
|
|
Is Bacillus anthracis G+ or G-? What is its morphology?
|
It is a G+, spore-forming rod
|
|
|
Name 2 symptoms of diphtheria.
|
pseudomembraneous pharyngitis (grayish white membrane) - lymphadenopathy
|
|
|
Name two non-lactose fermenting bacteria that invade intestinal mucosa and can cause bloody diarrhea.
|
Salmonella & shigella
|
|
|
T/F Enterobacteriaceae are oxidase negative and are glucose fermenters.
|
TRUE Use NH4
|
|
|
T/F: S. aureus food poisoning is due to the ingestion of bacteria that rapidly secrete toxin once they enter the GI tract.
|
FALSE: rapid onset of S. aureus food poisoning is due to injestion of PREFORMED toxin
|
|
|
What bacteria are G+, spore-forming, anaerobic bacilli?
|
Clostridia
|
|
|
What bacteria causes a malignant pustule (painless ulcer); black skin lesions that are vesicular papules covered by a black eschar?
|
Bacillus anthracis
|
|
|
What bacteria exhibits a 'tumbling' motility, is found in unpasteurized milk, and causes meningitis in newborns?
|
Listeria monocytogenes
|
|
|
What bacteria is catalase(-) and bacitracin-resistant?
|
Strep. agalactiae
|
|
|
What bacteria is catalase(-) and bacitracin-sensitive?
|
Strep. pyogenes
|
|
|
What bacteria is catalase+ and coagulase+?
|
Staph. aureus
|
|
|
What bacteria produces alpha-toxin, a hemolytic lecithinase that causes myonecrosis or gas gangrene?
|
Clostridium perfringens
|
|
|
What causes tetanus? (give bacteria and disease process)
|
Clostridium tetani: exotoxin produced blocks glycine release (inhibitory NT) from Renshaw cells in spinal cord
|
|
|
What disease is caused by Clostridium botulinum? What pathophys. does it cause?
|
Botulism: associated with contaminated canned food, produces a preformed, heat-labile toxin that inhibits ACh release---> flaccid paralysis.
|
|
|
What diseases can be caused by Staph. aureus?
|
Inflammatory disease: skin infections, organ abcess, pneumonia - Toxin-mediated disease: Toxic Shock Syn., scalded skin syndrome (exfoliative toxin), rapid onset food poisoning (enterotoxins)
|
|
|
What does catalase do?
|
it degrades H2O2, an antimicrobial product of PMNs.
|
|
|
What family of bacteria uses the O-, K-, and H-antigen nomenclature?
|
Enterobacteriaceae
|
|
|
What general type of bacteria are normal flora in GI tract but pathogenic elsewhere?
|
Anaerobes
|
|
|
What general type of bacteria grow pink colonies on MacConkey's agar?
|
Lactose-fermenting enteric bacteria
|
|
|
What is a lab diagnosis of diphtheria based on?
|
G+ rods with metachromatic granules; grows on tellurite agar. (Coryne=club shaped)
|
|
|
What is a major difference between Salmonella and Shigella observable in the lab?
|
Salmonella are motile; Shigella are nonmotile
|
|
|
What is a positive Quellung reaction?
|
if encapsulated bug is present, capsule SWELLS when specific anticapsular antisera are added.
|
|
|
What is the common site of infection for Mycobacterium tuberculosis?
|
the apicies of the lung (which have the highest PO2)
|
|
|
What is the toxin responsible for TSS is Staph. aureus?
|
TSST-1; it is a superantigen that binds to class II MHC and T-cell receptors---> polyclonal T-cell activation
|
|
|
What species is associated with food poisoning in meats, mayonnaise, and custard?
|
Staphylococcus aureus (this food poisoining usu. starts quickly and ends quickly)
|
|
|
What species is associated with food poisoning in poultry, meat, and eggs?
|
Salmonella
|
|
|
What species is associated with food poisoning in reheated meat dishes?
|
Clostridium perfringens
|
|
|
What species is associated with food poisoning in reheated rice?
|
Bacillus cereus ('Food poisoning from reheated rice? Be serious!')
|
|
|
What species is associated with food poisoning in undercooked meat and unpasteurized juices?
|
E. coli 0157-H7
|
|
|
What virulence factor of Staph. aureus binds Fc-IgG, inhibiting complement fixation and phagocytosis?
|
Protein A
|
|
|
What virulence factor of Strep. pyogenes also serves as an antigen to which the host makes antibodies?
|
M-protein
|
|
|
Which has an animal reservoir? (Salmonella or Shigella)
|
Salmonella: poultry, meat, eggs
|
|
|
Which is more virulent? (Salmonella or Shigella)
|
Shigella (10^1 organisms vs. Salmonella 10^5 organisms)
|
|
|
Which is motile? (Salmonella or Shigella)
|
Salmonella (think: salmon swim)
|
|
|
Why are anaerobes susceptible to oxygen?
|
they lack catalase and/or oxidase and are susceptible to oxidative damage
|
|
|
Why does TB usually infect the upper lobes of the lung?
|
M.tuberculosis is an aerobe; there is more oxygen at the apicies
|
|
|
T/F Cholera toxin is a bacteriophage.
|
T
|
|
|
TCBS Medium has an alkalotic pH. What kind of sugar does it ferment & what color are the colonies?
|
Sucrose. Yellow/ORANGE
|
|
|
Bacteria makes gas below the skin. Name bacteria & disease.
|
Clostridium. Sort tissue infection
|
|
|
Two distinct zones of hemolysis are produced on a blood agar. What is the bacteria/disease?
|
C. perferingens
|
