micro Flashcards Preview

uworld > micro > Flashcards

Flashcards in micro Deck (56):
1

HBsAG

-is a noninfective glycoprotein that forms spheres and tubules 22nm in diameter, it is part of the virus enveloppe
-it can be produced in enormous quantities so it is not considered a measure of viral reproductivitym unlike the HBcAg core antigen.

2

HbcAg

-nucleocapis core protein that resides within hepatocytes and aseembles virion it would be a measure of replication

3

Hep B has DNA polymerase that uses revere trascriptase

to replicated genome and produce an intermediate RNA template
Hep B is a hepadna virus it is partially DS, Circular and has an envelope

4

HBeAg

is a nuceleocapsis core and precore protein and a marker of high infectivity!
-the core component resides within hepatocytes and assembles virion, while the precore component directs secretion into blood.

5

hypopigmented, hyperpigmented skin patches or papules, in the setting of a hot and humid climate like the beach!

-pityriasis versicolor/tinea versicolor
-caused by fungus malassezia fur fur
-localized to stratum corneum
-does not tan, so becomes visible on suntanned skin
-diagnosis made by KOH treatment of skin scrappings --> spaghettic ameatballs appearance

streat: topical antifuncals or selenium-containing shampoo

6

transmission of meningococci usually occurs by exposure to respiratory droplets or direct contact with respiratory secretions

-adheres to mucosal epithelium via pillus in the pharynx then gains access to circulation
-IgA protease that facilitates the survival of the organism
-an antibody coating these pili would prevent pious-mediated attachment

7

IgA protease

step pneumo
neisseria
h influenzae

8

herpesviruses

HSV, CMV, EBV etc
are envelloped, linear, DS DNA

9

circular DNA

hepadnavirus (HBV)
pappilomavirus
polyomavirus (JC, BK)

10

the only ss DNA virus?

poor pervy single parvovirus B19

11

Which RNA viruses have no envellope?

Reovirus (colitvirus ROTAVIRUS)
Picornavirus (Hep A, polio, echovirus, rhino virus, coxsackievirus)
Hepevirus (HEV)
Calcivirus (norovirus)

they are ss (+) linear except reovirus which is DS linear

12

note all the SS (-) sense viruses have what kind of capsid?

helical
except HDV

13

The majority of ss (+) sense viruses have what kind of capsid?

icosahedral

14

retroviruses are

envelopped, ss (+) linear, icosahedral
HTLV and HIV

15

Some important envelopped, ss (-) linear viruses are

orthomyxovirus (segemented, flu)
paramyzovirues (non segmented, Mumps, RSV, parainfluenze virus/croup and rubeola/measles)

16

Rubella seams simliar to rubeola and mumps and friends but its not a parmyxovirus, what virus family is it?

togavirus
envelopped, ss (+) linear, icosahedral

EEE and WEE encephalitis are toga too

17

what are some arboviruses (mosquito and tick vector)?

EEE, WEE (toga)
Yellow fever, dengue, St. louis ecephalitis, WNV (flavi flava flav)
the above are enveloped, ss (+) linear

the below are helical, enveloped, ss (-) circular
california E, snadfly/rift valley fever, congo hemorrhagic fever, hanta virus-hemorrhagic fever

18

HDV alone is considered replication defective until?

it needs HBsAg of hep B to coat the HDAg of heptatitis D

19

The most common clinical manifestations of C. botulinum is?

diplopia (blurred vision), dysphagia (difficulty swallowing) and dysphonia

20

What does mycobacteria have that prevents the fusion of lysosome to phagosomes? perimitting it to persist ad a facultative intracellular organism within phagocytes?

sulfatides

21

Cord factor of mycobacteria

-establish virulence through neutrophil inhibition, mitochondiral destruction, and the induced release of TNF

22

aspergillus fumigatus and asthma

-generally only infects immunocompromied or deblillitated patients
-but it can colonize bronchial mucosa and complicated asthma and CF via hypersensitivitt rxn

-high serum IgE levels, eosinophilia, IgE and IgG serum antibodies to aspergillus.

23

Listeria is a facultative intracellular, gram-positive rod

-beta hemolytic
-tumbling mitility at 22 C
-multiple in as low at 4C
has listeriolysin O which can lyse vacuolar membranes which is selectively activated within acidified phagosomes. This allows it to escape the phagosome into the cytosol!
-need cell-mediated immune responses leading to macriphage activation to kill it

24

Asperigillus 45 (V branching), spores are normally cleared by the mucus and ciliated epithelium of respiratory tract
Colonizing aspergillosis

-occurs in OLD lung CAVITIES (form tuberculosis, emphysema or sarcoidosis)
-it does not invade in this case, but grows to form a fungus ball or aspergilloma

25

Invasive aspergillosis

develps in immunisuppressed patients, especially those with neutropenia --> necrotizing pneumonia and granulomas

it can become disseminated and spreads hematogenously to an organ

26

Allergic bronchopulmonary aspergillosis

patients with asthma
-titers of IgE antibodies to aspergillus are diagnostic

27

without preexisting endothelial damage leading to fibrin and platelt deposition at the cusps of valve leaflets, the viridins streptococci are unable to adhere to the valve and estabish an infection leading to endocarditis

-they bind by extracellular polysaccharides (dextran) to fibrin

28

BK virus is a DNA virus in the polyomavirus family
DS DNA circular no envellop

-in the immunocompromised:
nephropathy (typically post transplant when latent infection is reactivated)
-hemorrhagic cystitis

29

Which DNA viruses have no envelop?

Adenovirus
parvovirus
papillomavirus
polyomavirus

30

Which DNA viruses have circular DNA?

hepadnavirus (HBV)
pappilomavirus - no envellope
polyomavirus (JC, BK) -no envellope

31

Hepevirus is Hep E of HEV

non envelopped ss (+) linear
-spread through the fecal-oral route
-high mortality in infected pregnant women

32

What two drugs do we use to treat toxoplama gondii?

pyrimethamine and sulfadiazine

33

coccidioides immitis

-you will see a large spherule much larger than a RBC filled with little balls called endospores
-dimophic fungus
-SW USA
-can cause lung disease in immunocompitent and diseminated disease in immuno compromised
-KOH or silver stain

34

Most envelopped nucleocapsid viruese acquire their lipid bilaer envelop by budding though the plasma membrane of the host cell.

but?

Some actually acquire their membrane though the nuclear host cell membrane:
herepesvirus
HSV1,2, CMV, EBV, HSV 6, HSV 8
remember these are enveloped, DS linear DNA

35

How to prevent recurrences of genital herpes

-daily oral treatments of valacyclovir, acyclovir or famciclovir

36

Corynebacterium diphtheriae

non motile, gram negative rod
-found in clumbs resembling chines letters or in joined V and Y shaped chains
their cytoplasm contains metachromatic granules that stain with ANILINE dyes like METHLYENE BLUE
-tonsillar excudates!

Diptheria AB exotoxin that cataylyzes ADP ribosylation of protein elongation factor 2 EF 2.

EF2 is necessary for tRNA to insert a new amino acid into the growing protein chain during translation.

37

Hep C envelop proteins
note Hep C is envelloped ss (+) linear RNA virus, icosahedral (flaviviruses)

think flavi flav and his wild party of drugs and booze --> hep C

Envelop proteins (two glycloproteins):
-highly immunogenic
-not lost after recurrent replications
-not sequestered in hepatocytes but are present on the outermost surface of the virus and facilitate entrance into hepatocytes
-antigenic variety --> laging host antibodies

the glycoprotein is prone to frequent mutation, example is there is no 3'-4' exonuclease proofreading activity in its vision-encoded RNA polymerase

38

Treatment for pinworm enterobius vermicularis? (the one with the scotch tape test)

albendzole or mebendazole
-pyrantel pamoate is an alternate agent and is preffered in pregnant patients

39

How to treat loa loa and wuchereria bancrofti (lymphatic filariasis) infections?

diethylcarbanazine

40

How to treat strongyloided stercoralis and ochocerca volvulus?

ivermectin

41

How to treat schistosoma, clonorchis siensis and paragonium westermani?

praziquantel

42

parasite hints
biliary tract disease, cholangiocarcinoma

clonorchis sinensis

43

parasite hints
brain cyts and seizures

taenia solieum cysticercosis

44

parasite hints
hematuria, bladder cancer

schistosome haematobium

45

liver (hyatid) cyst

echinococcus granulosus

46

parasite hints:
microcytic anemia

ancylostoma, necator

47

parasite hints: portal HTN

shistosoma mansoni, schistosoma japonicum

48

parasite hints perianal pruitis

enterobius

49

parasite hints vitamin B12 deficiency

diphyllobothrium datum

50

Rheumatic fever is autoimmune following step pyogenes pharyngitis

-the antigenic similarity (epitopes) between bacterial antigens and normal self antigens in heart and CNS are believed to cause formation of anti-self antibodies resulting in rheumatic fever

-fever, arthritis, subcutanous nodules, erythema marginatum, involuntary rhthmic movements (sydeham chorea)

51

suspect legionella when

-recent exposude to contaminated water (cruise trip, hotel)
-radiographic evidence of pneumonia
-high fever
-neurological symptoms
-GI symptoms

pateints who smoke or have chronic lung disease are at higher risk.

hyponatremia lab finding!

52

dimorphic fungi

grow at molds at 25-30C
yeast at body temp 35-37C

53

Blastomycese dermatitidis

ohio and Mississippi river valleys, GREAT LAKES region, found in soil

causes: pneumonia sometimes disseminated

at 25C see branching hyphae
Biopsy large round yeasts with doubly refractile wall and single board based bud

54

secondary bacterial pneumonia after influenza infection

-elderly patients prone
-step pneumo, staph A, H. influenza common pathogens
-due to virally induced damage to the mucociliary clearence mechanisms in respiratory epitheliem leaves at risk for bacterial infection

55

Parvovirus B19 ss linear DNA

-slapped cheek
-the blood group P antigen, globoside is a parvovirus B19 receptor expressed on mature erythrocytes and erythroid progenitors.
-thus B19 often replicates in the BONE MARROW

child: febrile respiratory illness then followed by sudden appearance of red, flushed cheeks 2-5 day later

56

Picornaviruses are non envelopped ss (+) linear, icosahedral

their RNA is translated into one large peptide that is cleaved by proteases into functional viral proteins