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75 Cards in this Set

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of the A/B toxin:
1. what is the function of the A subunit?
2. what is the function of the B subunit?
1. A subunit has toxin activity
2. B subunit is required for binding and translocation
give two examples of toxins that have the A/B toxin subunits.
1. cholera toxin
2. pertussis toxin
which two bacteria are the "most important" in regards to their superantigen production?
1. Staph aureus
2. Strep pyogenes
superantigens cause?
polyclonal activation of T cells leading to the release of proinflammatory cytokines
describe toxin production by Bacillus anthracis
- has a protective antigen
- this antigen is cleaved by the host protease
- pore is formed
- Lethal factor + PA = lethal toxin
- Edema factor + PA = edema toxin
upon cellular entry PA binds to either lethal factor or edema factor
the cholera toxin targets which protein?
G proteins
(alters ion transport)
the pertussis toxin targets which protein?
G protein
results in an increase of cAMP
some toxins result in cell cycle arrest of the host cell. In what phase are these cells arrested in?
G2
what is the most potent toxin known?
Botulinum toxin
(from Clostridium botulinum)
both the botulinum and the tetanus toxin alter what?
vesicular trafficking in the nervous system
via what mechanism do many bacteria induce apoptosis?
via activation of the caspases
give two examples of bacteria that induce apoptosis
1. shigella
2. salmonella
*many bacteria induce apoptosis*
give an example of a bacteria that BLOCKS apoptosis
Why would it want to do that?
Rickettsia rickettsii (RMSF)
*it is an obligate intracellular parasite
type III secretion is characterized by?
secretion of proteins across 3 membranes
(bacterial cytosol to eukaryotic cytosol)
which type of secretion do conjugal DNA transfer systems use?
Type IV secretion
besides DNA, what else is transported via type IV secretion? (2)
1. nucleoprotein complexes
2. multisubunit toxins
acute lymphadenitis is most often caused by?
local trapping of microbes
diffuse lymphadenitis is most often caused by? (3)
viral infection
bacteremia
diseases caused by exotoxins
which type of infections would cause acute suppurative lymphadenitis?
pyogenic (pus-forming) infections
(these are characterized by acute inflammatory neutrophilic rxn and are caused by drainage of bacteria from the infected site)
which two bacteria are known to cause acute suppurative lymphadenitis?
staph aureus
group A strep
(above are referred to as the pyogenic cocci)
which organism, responsible for cat-scratch disease, causes a regional self limiting lymphadenitis?
Bartonella henslae
(gram negative rod)
what happens in a Bartonella henslae infection?
- starts as a small papule 3-10 days after infection
- organism spreads to regional lymph nodes
*host usually limits the infection here
which organism causes "uncontrolled cat scratch disease"
Bacillary angiomatosis
bacteria multiply freely and are disseminated into the bloodstream
*sepsis occurs
* get skin erruptions resembling Kaposi's sarcoma
which one of 3 antibiotics would we use to treat cat scratch disease?
erythromycin
doxyxycline
azithromycin
what is a scrofula?
TB that has caused cervical lymphadenitis
*caused by spread from the lung
*firm red painless mass on SCM or in supraclavicular area
inguinal lymphadenopathy is caused by what three things?
1. STDs
2. Plague
3. Tularemia
lymphadenitis caused by Haemophilus decreyi (an STD) is known as?
a chancroid
organism causing the plague?
Yersinia pestis
(small gram - rod)
are most Yersinia infections intra or extra cellular?
extracellular
(although it is a facultatively intracellular pathogen)
in current times, where in the US are most Yersinia infections seen?
southwest
Yersinia pestis has a bipolar staining. what does it look like in the blood?
safety pin appearance
extracellular
how is the Bubonic plague transmitted?
flea bites
in Bubonic plague:
describe what happens from the flea bite up until death
- infection spreads from flea bites to regional lymph nodes
- inflammed lymph nodes form buboes (painful)
- bacteria spreads from lymph nodes to lung, liver, spleen
- death from septic shock
how does septicemic plague differ from bubonic plague?
disease progression occurs without the formation of buboes
what is the difference between pneumonic plague and the other two types of plague?
direct inoculation into the lung via aerosols
- almost always fatal
- human to human transmission
what aspect of Yersinia pestis is used as a diagnostic tool?
F1 capsule
function of F1 capsule?
prevents phagocytosis
function of Pla (plasminogen activator) protease in Yersinia pestis?
helps in dissemination from peripheral tissue
also cleaves C3
treatment for Yersinia pestis?
1. supportive care
2. antibiotics (streptomycin, doxycycline, quinolones)
what is a major "attribute" of anthrax that contributes to its virulence?
it can form endospores
what are the three forms of an anthrax infection?
In order of severity:
1. Cutaneous
2. Gastrointestinal
3. Inhalational
treatment for anthrax?
penicillin G (sometimes with an aminoglycoside)
prophylactic treatment for anthrax?
cipro
must take for over 2 months because of endospores
describe the pathogenesis of inhalational anthrax up until death
- inhaled endospores germinate in alveolar macrophages
- bacteria replicate in regional lymph nodes
- progresses to mediastinal hemorrhage
which organism causes Tularemia?
Francisella tularensis
what is notable about F. tularensis?
probably the most infectious bacteria known
(infectious dose as low as 10-50 organisms)
is F. tularensis intra or extra cellular?
F. tularensis is a facultative intracellular parasite
treatment for Tularemia?
streptomycin or other aminoglycoside
prophylaxis for Tularemia?
doxycycline
what is notable about the clinical course of Leptospirosis?
Biphasic course (typical of spirochetes)
1. sepsis
2. menigneal inflammation, rash, uveitis
relapsing fever is most often caused by which microorganism?
Borrelia recurrentis
B. recurrentis is transmitted by?
lice
(when lice are crushed they enter through mucous membranes or broken skin)
describe the relapsing fever seen with Borrelia recurrentis infection
first fever lasts 3-6 days
fever recurs in 7-10 day intervals
(fever is present when spirochetes are in blood, when there is no fever they are in organs)
what is the leading cause of bacteremia and meningitis in neonates?
group B Strep
most common symptom of Group B Strep infection in the neonate?
meningitis
what are the two major types of Rickettsial infections?
1. Typhus group
2. Spotted Fever group
Is rickettsia an intra or extra cellular parasite?
obligate intracellular parasites
where do Rickettsia multiply?
in vascular endothelium - this causes pathology in skin, CNS, liver
describe the pathogenesis of Rocky Mountain Spotted Fever
Rickettsia rickettsii replicate at the site of the tick bite
-spread to blood and vascular endothelium of lungs, spleen, skin, brain
- 1 wk incubation period
- fever, headache, myalgia, respiratory symptoms
- maculopapular rash
- splenomegaly and sepsis occur
what is the mortality rate of Typhus in epidemic areas?
40%
what is the animal reservoir of endemic Typhus?
rodent
Bartonella quintana causes?
trench fever
what is characteristic of trench fever?
intense tibial pain
fever recurs every 5 days with decreasing severity
Q fever is caused by?
Coxiella burnetti
(coccobacillus)
is coxiella an intra or extra cellular parasite?
obligate intracellular parasite
(infects primarily monocytes and macrophages)
how is Q fever diagnosed?
serology
Erlichia is transmitted by?
tick bites
HHV-6 causes? and has a possible association with ?
causes exanthum subitum (rash)
possible association with MS
HTLV-1 is associated with what diseases? (2)
1. Adult T-cell leukemia/lymphoma
2. HTLV associated myelopathy/tropical spastic paraparesis
HTLV-2 is associated with? (1)
HTLV-associated myelopathy/tropical spastic paraparesis
What is the causative agent of infectious mononucleosis?
EBV
EBV is also assiciated with what 2 neoplasms?
1. Burkitt's lymphoma
2. nasopharyngeal carcinoma
where does the latent EBV infection "hang out"
B lymphocytes
describe the virion and capsid seen in EBV
enveloped virion
icosahedral capsid
structurally, what makes EBV different from other herpes viruses?
one predominant glycoprotien on cell surface