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Microbiology section 3
Second Micro test. Spring 2012. Section 3.
221
Microbiology
Graduate
01/16/2012

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Term
Describe the bacteria that causes diphtheria.
Definition
It is called Corynebacterium diphtheriae. It is a small, Gram positive club.
Term
What are the three domains of the diphtheria toxin.
Definition
A: the section that is released into and damages the cell
B: binds to cell membrane
T: inserts into membrane of the endocytotic vesicle
Term
Which bacteria forms a pseudomembrane in the throat?
Definition
Corynebacterium tuburculosae
Term
How is diphtheria transmits?
Definition
Inhalation of droplets from an infected person.
Term
Why kind of Strep causes Strep throat and scarlet fever?
Definition
Streptococcus pyogenes. (Group A Strep)
Term
What does DPT stand for?
Definition
diphtheria, pertussis, tetanus
Term
What are exogenous bacteria?
Definition
Those that are not normally found in the human body. They cause primary infections.
Term
What are opportunistic infections?
Definition
They are caused by normal flora when conditions are right.
Term
What kind of bacteria are most enteric bacteria?
Definition
Gram negative rods.
Term
Which bacteria causes Lyme disease?
Definition
Borrelia burgdorferi
Term
Which kinds of bacteria (shape and Gram) cause most diseases?
Definition
Gram+ cocci and Gram- rods
Term
Which major diseases are caused by Gram negative cocci?
Definition
gonorrhea and meningitis
Term
Which two major diseases are caused by Mycobacterium species?
Definition
tuberculosis and leprosy
Term
Describe the bacteria that causes whooping cough. (Shape, metabolism, Gram)
Definition
Bordetella pertussis. Strictly aerobic, Gram negative rod.
Term
During a pertussis infection, when do you get the coughs with whooping sound?
Definition
2-4 wks
Term
Which area does B. pertussis colonize?
Definition
the pharynx, larynx, trachea, and bronchi
Term
Why is B. pertussis virulent?
Definition
It produces adhesins that prevent it from becoming swept away by binding to cilia. (Filamentous hemoglutin)

Also, it produces the pertussis toxin. The toxin can act as an adhesin or harm host cells.
Term
What does pertussis toxin do?
Definition
It increases intracellular cAMP, which interferes with normal signaling.
Term
What were the three original fungal phyla?
Definition
Basidiomycota, Ascomycota, and Zygomycota.
Term
Are fungi mobile? Can they fix carbon?
Definition
With very limited exception, they are non-motile. They are heterotrophs (they cannot fix carbon).
Term
Which fungal form consists of hyphae that form a mycelium?
Definition
the mold form
Term
What does it mean for a fungus to be dimorphic?
Definition
It can switch between the yeast and mold forms.
Term
Oftentimes, hyphae are divided into separate compartments by barriers called ____.
Definition
septae
Term
Asexual spores are called _____ or ____, while sexual spores are called _____.
Definition
anamorphs; conidia; teleomorphs
Term
Sometimes, spores simply ___ off of existing cells. Other times, they are released from a lollipop-shaped _____.
Definition
bud; sporangiospore
Term
Polyenes bind to ____, interfering with cell ____.
Definition
ergosterol; membranes
Term
Azoles prevent ____ synthesis, which prevents ____ synthesis.
Definition
ergosterol; membrane
Term
What do echinocandins do?
Definition
They prevent fungal cell wall synthesis.
Term
What two classes of fungal antibiotics are most commonly used?
Definition
Azoles and echinocandins.
Term
Mircosporum, Trichophyton, and Epidermophyton cause _____ fungal infections, such as ringwom and athlete's foot.
Definition
cutaneous
Term
Chromoblastomycosis, phaeohyphomycosis, mycetoma, and sporotrichosis are all examples of _____ fungal infections.
Definition
subcutaneous
Term
______ is sometimes called "valley fever" and is found in the southwest US and Mexico.
Definition
Coccidioidomycosis
Term
Of the endemic fungal diseases we looked at, which is localized in the Ohio river valley area?
Definition
Histoplasmosis
Term
C. albicans is ____, meaning it can switch from its blastoconidia form to hyphae.
Definition
dimorphic
Term
What is a characteristic that all the opportunistic fungi share?
Definition
They can grown well at 37 degrees C.
Term
Of the opportunistic fungi we looked at, which is inhaled and binds to fibrinogen?
Definition
Aspergillus
Term
Which opportunistic fungus has a very thick capsule and can invade CSF?
Definition
Cryptococcus
Term
What is a zygospore?
Definition
When two fungi mate sexually, their hyphae are connected by the zygospore, from which a sporangiospore arises and releases spores.
Term
Where in the body is a Rhizopus infection typically localized?
Definition
In the rhinocerebral region. It can spread to the orbits as well.
Term
All Staphylococci are ____ positive. However, only Staph aureus is ____ positive.
Definition
catalase; coagulase
Term
Describe Staph.
Definition
Gram positive facultative cocci.
Term
What are some diseases caused by Staph?
Definition
abscesses, SSSS, TSS, and food poisoning
Term
What is exfoliatin? What disease is it involved in?
Definition
Exfoliatin is a toxin produced by Staph. It is involved in SSSS.
Term
Superantigens cause many T cells to differentiate, leading to excess production of ___.
Definition
interleukin-2
Term
Streptococci are classified according to their hemolysis of RBCs. Describe the three different hemolysis patterns.
Definition
Alpha: greenish zone around colony
Beta (complete hemolysis): complete clearing around colony
Gamma: colony does not cause hemolysis
Term
In what ages is strep throat most common?
Definition
Kids 5-10 yrs old.
Term
Which genus causes impetigo and rheumatic fever?
Definition
Streptococcus
Term
Which disease causes "strawberry tongue"?
Definition
scarlet fever caused by Strep. pyogenes
Term
Which causes TSS from tampons, Strep or Staph? Which is more deadly? Which important virulence factor do both produce.
Definition
Staph TSS is associated with tampons. Strep TSS is more deadly. Both produce superantigens.
Term
How is erisypelas different from impetigo?
Definition
Both are Strep infections, but erisypelas occurs in a deeper layer of skin than impetigo.
Term
If strep pharyngitis is not treated with penicillin, the patient may later experience ____, a delayed sequela.
Definition
rheumatic fever
Term
These are virulence factors for Strep:
M-protein
F-protein
Streptolysin
What do they do?
Definition
M-protein: antiphagocytic
F-protein: an adhesin
Streptolysin: lyses leukocytes
Term
What is M protein?
Definition
A virulence factor for Strep A. It's a long protein on the strep cell surface that prevents phagocytosis.
Term
What are three diseases causes by Strep pneumoniae?
Definition
pneumonia, otitis media, and meningitis
Term
Describe the grouping of the cocci of Strep A and Strep pneumoniae.
Definition
Strep A: long chains
Strep pneumoniae: short chains, pairs, or solo
Term
What are two important diagnostic features for pneumococci?
Definition
1. bile solubility (due to autolysin)
2. resond to Quellung test (capsules swell)
Term
What feature of pneumococci allows them to resist phagocytosis in the lung?
Definition
their capsule
Term
Pnemococci are able to cause meningitis because they can cross the _____.
Definition
blood-brain barrier
Term
Which is more susceptible to penicillin, staph or strep?
Definition
strep
Term
What is the most abundant bacteria in the gut?
Definition
E. coli
Term
Which bacteria cause dysentery?
Definition
Both E. coli and Shigella species.
Term
In a serotype, what do the O and H refer to?
Definition
O-antigen: LPS side chains
H-antigen: flagella
(K-antigen: the capsule)
Term
Shigella has a ___ infectious dose.
Definition
low
Term
Often, ____ infections occur at day cares.
Definition
Shigella
Term
Is Salmonella part of normal flora?
Definition
Not for humans.
Term
Like most enteric bacteria, Vibrio cholerae is a Gram _____ ____.
Definition
negative rod

(however, it is curved)
Term
In terms of colonization, what separates watery diarrhea from bloody diarrhea and dysentery?
Definition
With watery diarrhea, bacteria only colonize the enteric cell surface. With more severe diarrhea, they invade the cells themselves.
Term
How do diarrhea causing bacteria survive the fast flow of the small intestine?
Definition
They use their pili to attach to the tract.
Term
What are the two virulence factors of V. cholerae?
Definition
Tcp pili and cholera toxin.
Term
Describe the structure of cholera toxin. Which subunit is released into the cell?
Definition
There is one alpha subunit and 5 identical beta subunits. The A unit is released into cells (leads to excess cAMP).
Term
Which bacteria causes typhoid fever?
Definition
Salmonella. It's a secondary infection from salmonella infection. (People can be carriers.)
Term
Salmonella can cause typhoid fever when it is able to invade what?
Definition
lymph nodes and blood cells
Term
Which organ is the seat of chronic typhoid infection?
Definition
the gallbladder
Term
Does V. cholerae invade the cell?
Definition
No. It causes watery diarrhea.
Term
Describe the shape/Gram of Neisseria gonorrhoeae.
Definition
Gram negative diplococci
Term
Who is more likely to contract gonorrhea after one exposure, men or women?
Definition
women
Term
Where is the primary site of infection for gonorrhea?
Definition
Men: urethra
Women: endocervix
Term
If a young female has arthritis of the knee, which STD may be to blame?
Definition
gonorrhea
Term
Does the gonococcus enter the host cell?
Definition
Yes, via endocytosis.
Term
Which component of the gonococcus is responsible for most of the symptoms of gonorrhea?
Definition
LOS (lipooligosaccharide), it's endotoxin
Term
What does P1 do for the gonococcus?
Definition
Prevents fusion of lysosome with phagosome.
Term
Why has is been difficult to develop a vaccine against gonorrhea?
Definition
The bacteria constantly undergoes antigenic variation. E.g. when the cell recognizes one kind of pilin, the bacteria will begin producing another.
Term
What class of drugs is used to treat gonorrhea?
Definition
cephalosporins
Term
Which bacteria causes syphilis?
Definition
Treponema pallidum
Term
In what stage of syphilis does chancre appear?
Definition
primary syphilis
Term
In what stage of syphilis does a body-wide rash appear?
Definition
secondary syphilis
Term
After syphilis becomes latent, what can happen?
Definition
1. nothing("cure")
2. secondary stage recurs
3. tertiary syphilis begins
Term
What happens during tertiary syphilis?
Definition
Bacteria leaves the blood stream and invades the organs.
Term
What is used to treat syphilis?
Definition
Penicillin
Term
What is the most common bacterial STD?
Definition
chlamydia
Term
Chlamydia is very ____, allowing it to pass through some filters. It is an obligate _____ _____.
Definition
small; intracellular parasite
Term
Is Chlamydia trachomatis Gram - or +?
Definition
Gram -
Term
If you see the symptoms of gonorrhea, but cannot find any Gram negative cocci, what does the patient likely have?
Definition
chlamydia
Term
If chlamydia is an obligate intracellular parasite, how can it be transmitted through a towel?
Definition
They exist as EBs (elementary bodies), which can stay outside cells w/o replicating.
Term
What is trachoma?
Definition
An eye infection caused by chlamydia.
Term
Chlamydia replicates within a cell as _____ bodies. When the cell lyses, it releases ____ bodies.
Definition
reticulate; elementary
Term
What is used to treat chlamydia?
Definition
Azithromycin and doxycycline. Erythromycin for children and pregnant women.
Term
Gram and shape of Heliocobacter pylori.
Definition
Gram negative rod. Spiral shaped (not a spirochete).
Term
At what times is pain from gastritis and peptic ulcers likely to occur?
Definition
2-3 hours after a meal and during the middle of the night.
Term
H. pylori is safe within the mucin layer, but how does it survive its journey there?
Definition
It secretes urease, which neutralizes the acid around itself.
Term
Why are ulcers vulnerable to acid?
Definition
The LPS of H. pylori breaks down the mucin layer.
Term
H. pylori attaches to epithelial cells using several different kinds of _____.
Definition
adhesins
Term
What is the purpose of a urease breath test?
Definition
A pt drinks a solution with labeled urea. If H. pylori is present, the urea will be broken down to ammonia and exhaled. This test checks for H. pylori.
Term
For ___ percent of people, a ___ week course of antibiotics will cure ulcers.
Definition
80; 2
Term
How is Borrelia burgdorferi visualized?
Definition
dark-field microscopy
Term
Which bacteria causes Lyme disease?
Definition
Borrelia burgdorferi
Term
Which kinds of ticks carry B. burgdorferi?
Definition
Ixodes (deer tick)
Term
What is the symptom of stage 1 Lyme disease?
Definition
erythema migrans
Term
What happens during stage 2 Lyme disease?
Definition
Dissemination. Fatigue, headache, pain, fever, etc. It's kind of like the flu.
Term
What happens during stage 3 Lyme disease?
Definition
Arthritis, Bell's palsy, meningitis, arrhythmia.
Term
What is the treatment for Lyme disease?
Definition
Doxycyline and Lyme disease vaccine.
Term
How does tuberculosis grow?
Definition
Slowly. In cords.
Term
How is tuberculosis transmitted? How many bacteria are needed?
Definition
It is inhaled. Only a few bacteria are necessary for TB infection.
Term
How does TB survive in the lungs?
Definition
The unique cell wall makes them resistant to destruction by macrophages.
Term
What happens during primary TB?
Definition
Usually, not much if the patient is healthy. The body will form tubercles.
Term
What happens during secondary TB?
Definition
Lesion break down. Tissue can become necrotic. Bloody sputa. TB is contagious.
Term
High lipid content and ____ acid make _____ species like the bacteria that causes Tb very tough.
Definition
mycolic; Mycobacterium
Term
How does M. tuberculosis survive in the macrophage?
Definition
Prevent fusion with the lysosome. Escapes into cytoplasm. Inhibits activation.
Term
How is Tb diagnosed?
Definition
Tb skin test (most common), culture test, chest x-ray (for granulomas).
Term
What is unique about Tb treatment?
Definition
It lasts 6-9 months. Several different drugs must be used in concert.
Term
What drug can cause intrinsic staining on teeth?
Definition
Tetracycline used in utero. This is cosmetic only. The only treatment is veneers.
Term
What rinse may cause extrinsic staining? Why?
Definition
Chlorhexidine. It kills bacteria, causing them to release their pigments.
Term
What is material alba?
Definition
A loosely attached accumulation of host cells, bacteria, and food.
Term
How can dental plaque be removed?
Definition
Only mechanically.
Term
What is the difference between calculus and plaque?
Definition
Calculus is calcified plaque. It is always covered with a layer of uncalcified plaque.
Term
What is planktonic bacteria?
Definition
The bacteria is suspended in solution. For my purposes, it's basically bacteria in saliva as opposed to bacteria in biofilm.
Term
Biofilms exhibit primitive "_____ systems."
Definition
circulatory
Term
What are the three steps of biofilm formation?
Definition
Attachment, growth, and detachment.
Term
How do the nutritional needs of plaque in the gingival sulcus differ from those on the tooth surface?
Definition
In the gingival sulcus, bacteria will have to live off protein instead of carbs. This is because crevicular fluid is derived from serum, not saliva.
Term
How do the bacteria in a biofilm interact with one another?
Definition
They can cooperate to enhance metabolic activity, or they can have antagonistic effects on one another.
Term
What four factors explain plaque's resistance to host defenses and antibiotics?
Definition
1. slow penetration
2. stress response of inner layers
3. altered microenvironment
4. persister cells
Term
What is quorum sensing?
Definition
A process that allows bacterial cells to sense their own density. The result will lead to altered behavior.
Term
Describe the composition of the acquired pellicle.
Definition
It is a cell-free film made mostly of proteins and glycoproteins.
Term
How long does it take the pellicle to appear after teeth cleaning? How long to mature?
Definition
2 hours to appear. 7 days to mature.
Term
What causes firm attachment of bacteria to the pellicle?
Definition
Bacterial adhesins
Term
What types of bacteria attach to the pellicle during plaque initiation?
Definition
Streptococcus and Actinomyces. Gram positive (both cocci and rods).
Term
At late stage of plaque formation, bacteria are likely to be Gram ____.
Definition
negative
Term
What is happening to the tooth surface microenvironment as plaque forms?
Definition
Oxygen and carb levels go down. Temperature increases.
Term
What happens to the prevalence of cocci as plaque matures?
Definition
Cocci are replaced with rods and filaments.
Term
What characterizes the metabolism of late colonizers?
Definition
They are increasingly anaerobic.
Term
How do bacteria in subgingival plaque differ from those in supragingival plaque?
Definition
They are dominated by Gram -, anaerobic bacteria. They are mainly proteolytic.
Term
What are the three phases of plaque initiation?
Definition
random contact, reversible adsorption, and firm attachment
Term
Re the acquired pellicle and the bacteria, what is the ligand and what is the receptor?
Definition
The receptors are proteins on the pellicle and the ligands are adhesins on the surface of bacteria.
Term
What are the five initial colonizers?
Definition
1. Strep sanguis
2. Strep gordonii
3. Strep oralis
4. Strep mitis
5. Actinomyces naeslundii
Term
Large ____ microcolonies formed during early stages of plaque formation are made primarily of _____ shaped cells.
Definition
columnar; coccoid
Term
Where will you find iron, in subgingival or supragingival plaque?
Definition
subgingival (blood products derived from GCF)
Term
Describe the components of the corn cob.
Definition
A rod or filamentous center surrounds by cocci. (Gram+ in early stages. Gram- in later stages.)
Term
When will you find early supragingival plaque? What kinds of organisms are there?
Definition
0-3 days. Gram+ rods and cocci. Facultative anaerobes. The organisms are NOT PATHOGENIC. They are well-tolerated by the host.
Term
Describe the organization of early supragingival plaque colonies.
Definition
Columnar microcolonies.
Term
Name the six secondary colonizers.
Definition
1.Fusobacterium nucleatum
2. Tannerella forsythis
3. Prevotella intermedia
4. Porphyromonas gingivalis
5. Treponema denticola
6. Aggregatibacter actinomycetemcomitans
Term
When is the supragingival plaque fully matured?
Definition
Around 3 weeks. Subgingival plaque continues to develop.
Term
What aspect of bacteria cause inflammation of the gingiva?
Definition
The LPS of Gram- bacteria. (Bacteria is able to permeate the junctional epithelium.)
Term
The JE is more ____ than the SE.
Definition
permeable
Term
What/where are capnophilic bugs found?
Definition
They are found in subgingival plaque. They like carbon dioxide.
Term
What kinds of bacteria are found in subgingival plaque?
Definition
Gram- anaerobes.
Term
The deepest layer of the subgingival plaque will have a wall of _____ between it an the junctional epithelium.
Definition
neutrophils
Term
What are the plaque-induced periondontal diseases?
Definition
gingivitis and periodontitis
Term
What is periodontitis?
Definition
Inflammation and destruction of the attachment apparatus.
Term
How long does it take filamentous and slender rod-shaped bacteria to appear after cessation of OH?
Definition
2-4 days
Term
How long does it take spirochetal organisms to appear after cessation of OH?
Definition
10 days
Term
How many species of bacteria have been isolated in the oral cavity?
Definition
over 700
Term
What is the non-specific plaque hypothesis?
Definition
Doesn't matter what the bugs are, just how many are there.
Term
What is the specific plaque hypothesis?
Definition
Specific organisms in plaque cause gingivitis.
Term
Many oral bugs suspected in periodontal disease are anaerobic. How does that make it difficult to fulfill Koch's postulates?
Definition
They are very difficult to grow in culture.
Term
Who is Sigmund Socransky?
Definition
An oral microbiologist who modified Koch's postulates to work for periodontal disease.
Term
Describe Socransky's modification re numbers.
Definition
The putative pathogen must be present in higher numbers in diseased individuals.
Term
(Socransky) The organism should exhibit _______ relevant to the initiation and progression of the disease. There should be a ___ response to the organism.
Definition
virulence factors; host
Term
Is there a direct correlation between the amount of plaque on an individual's teeth and the severity of periodontal disease? Which hypothesis does this support?
Definition
No. This supports the specific plaque hypothesis.
Term
What is the main thing you can do with dark field microscopy?
Definition
Determine bug morphology.
Term
What are the two main recent advances that have improved the study of periodontal bugs?
Definition
Advances in bacterial culturing and molecular genetic approaches.
Term
What are some other names for necrotizing ulcerative gingivitis?
Definition
Trench mouth. Vincent's disease.
Term
Which periodontal disease is characterized by punched out papillae with a pseudomembrane?
Definition
necrotizing ulcerative gingivitis
Term
Which bacteria are likely involved in necrotizing ulcerative gingivitis?
Definition
Spirochetes, Fusobacteria species, Selenomonas species, and Prevotella species. It's difficult to say if there is a causal relationship.
Term
Which periodontal disease typically involves permanent incisors and first molars and typically self-arrests?
Definition
Localized aggressive periodontitis (formerly called localized juvenile periodontitis)
Term
Which bacteria is most closely related with localized aggressive periodontitis? What are some characteristics of this bacteria?
Definition
Aggregatibacter actinomycetemcomitans (Aa). Gram-, capnophilic, non-encapsulated, non-motile. In subgingival plaque.
Term
In chronic periodontitis, what correlates with the amount of attachment loss?
Definition
the amount of microbial deposits
Term
Which bugs are associated with chronic periodontitis?
Definition
P. gingivalis, Tannerella forsythia, Aa, Treponema denticola
Term
Is Aa implicated in chronic or aggressive periodontitis.
Definition
Both, but much more in aggressive periodontitis.
Term
How are P. gingivalis and Aa similar?
Definition
Both Gram-, both non-motile.
Term
How is P. gingivalis different from Aa?
Definition
Pg is an obligate anaerobe. Aa is a capnophile. Pg has a capsule. Aa does not.
Term
Which virulence factors should a periodontal pathogen display?
Definition
Colonize a niche, invade tissues, obtain nutrients, evade immune system.
Term
What are the three virulence factors of Aa I would like to remember?
Definition
1. Endotoxin
2. Leukotoxin
3. Cytolethal distending toxin
Term
What does Aa endotoxin do?
Definition
Elicits bone resorption and inflammation.
Term
What does Aa leukotoxin do?
Definition
Kills leukocytes.
Term
What does Aa cytolethal distending toxin do?
Definition
Kills epithelial cells.
Term
Porphyromas gingivalis displays the ability to invade ________.
Definition
human cells
Term
What are the three bugs that are suspecting in periodontal disease?
Definition
P. gingivalis, Tannerella forsythia, and Treponema denticolis
Term
According to the ecoligic plaque hypothesis, with plaque accumulation, GCF flow is ____ and electrical potential is ____.
Definition
high; low
Term
What is the ecologic plaque hypothesis (in a nutshell)?
Definition
When the ecology supports the growth of disease causing bugs, they can proliferate past a certain threshold and cause periodontal disease.
Term
Does periodontal disease represent an exogenous or opportunistic infection?
Definition
More so opportunistic. These bugs are likely part of our normal flora. But sometimes maybe they're not.
Term
Which bugs cause severe caries in gnotobiotic rats?
Definition
Lactobacilli and S. mutans
Term
"Caries-resistant hamsters are not truly caries resistant." Explain.
Definition
They just do not carry cariogenic bacteria as part of their normal flora, but when infected, they develop caries.
Term
What kinds of bacteria cause root surface caries?
Definition
Actinomyces viscosus and Lactobacilli.
Term
Which bacteria have a strong association with SS, PF, and RS caries?
Definition
Mutans Streptococci. (incl. S. mutans, S. sobrinus, S. rattus, and S. cricetus)
Term
Are S. sanguis and S. mitis cariogenic?
Definition
They have a weak association with pit and fissure caries.
Term
What is aciduricity (re caries)?
Definition
Capacity of a bacteria to maintain metabolism at low pH.
Term
What is antigen I/II?
Definition
Strep adhesins that allow them to attach to the acquired pellicle and to each other.
Term
What goes glucan binding protein (GBP) do?
Definition
Binds S. mutans to the extracellular glucanms.
Term
All E. coli have ____ pili. In addition, enterotoxigenic E. coli has ____ pili and _______, while uropathogenic E. coli have ____.
Definition
common; Type 1; CFA I/II; P pili
Term
Other than pili, what is a bacterial adherence mechanism we discussed?
Definition
Afimbrial adhesins (surface proteins)
Term
What are the two kinds of adhesins produced by B. pertussis?
Definition
Filamentous hemagglutinin (Fha) and Pertussis toxin (Ptx)
Term
Initial attachment of gonococcus is mediated by ____. Then the surface protein ____ mediates a much tighter interaction.
Definition
pili; P2
Term
What are some kinds of bacteria that can invade cells?
Definition
Chlamydia, Shigella, Salmonella
Term
How do bacteria enter non-phagocytic cells?
Definition
1. Zipper mechanism or
2. Trigger mechanism
Term
How does Yersinia enter cells?
Definition
the Zipper mechanism
Term
How does Salmonella enter cells?
Definition
The "trigger" mechanism. (Changes cytoskeletal structure of cell.)
Term
How can bacteria evade complement?
Definition
1. mask surface w/ capsule (S. aureus)
2. Coat themselves with IgA
3. Produce C5a peptidase (S. pyogenes)
4. LSP blocks access (Salmonella)
Term
What is streptolysin?
Definition
Enzyme produced by S. pyogenes. Capable of lysing a phagocyte. (also causes hemolysis)
Term
Which two surface proteins will prevent opsonization?
Definition
Protein M (staph, strep) and Protein A (S. pyogenes)
Term
1 gram of tetanus toxin is enough to kill _____ people.
Definition
10 million
Term
How does cholera toxin work? (and AB toxin arrangement)
Definition
It hijacks host cell signal transduction. (A-B5)
Term
How does diphtheria toxin work? (and AB toxin arrangement)
Definition
It blocks protein synthesis. (A-B single polypeptide)
Term
How does TSS toxin work?
Definition
As a superantigen (S. aureus)
Term
Group A Strep releases the degradative enzyme ______.
Definition
hyaluronidase
Term
Why is lipid A (endotoxin) not toxic unless the bacteria is lysed?
Definition
It is usually buried in the membrane.
Term
How does endotoxin work?
Definition
It activates a macrophage to activate PGs, ILs, TNF, complement, etc., leading to tissue damage and inflammation.
Term
How can bacteria trigger an autoimmune response?
Definition
Sometimes, the bacteria present an antigen that resembles the host cell.
Term
With tuberculosis, it is not the bacteria themselves that cause damage, but rather inflammation due to _____.
Definition
cytokines
Term
What does the Shigella plasmid do?
Definition
Encode for cell invasion properties.
Term
What are pathogenicity islands?
Definition
Gene segments that are transposable between bacteria.
Term
What are pathogenicity islands?
Definition
Gene segments that are transposable between bacteria.
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