Micro, Ass 12 – Flashcards

Core or Capsid protein in HIV, encoded by the gag gene;

p24 levels are used to determine viral load by ELISA which detects antibodies to the p24 protein capsid and HIV.

HIV surface protein that mediates receptor binding;

Encoded by the env gene

HIV surface protein that mediates membrane fusion activity;

Encoded by the env gene;

Drug target* of Enfuvirtide, a fusion inhibitor which binds to gp41 and pervents fusion of the viral and host membranes preventing viral entry into host cells.

FALSE

+ Sense*

Is ssRNA and is enveloped

HIV accessory protein;

Enhances the rate of proviral genes integrated into the host genome.

HIV accessory protein;

Facilitates transport of unspliced viral mRNAs out of the nucelus for translation in the cytoplasm

Chemokine receptor on Macrophages;

Along with CXCR4, a possible secondary binding in addition to CD4+ to allow viral entry into host cells;

Drug Target* of Maraviroc which binds and inhbits viral fusion with host cell membranes;

Mutations in CCR5 are associated with resistance to HIV infection.

True (though CCR5 can also work);

It is required that HIV bind CD4+ and one of the chemokine receptors (either CXCR4 or CCR5) in order for membrane fusion and viral entry into the host cell to take place.

FALSE;

During the latent phase CD4+ T cells do rebound somewhat but then begin a steady decline. Also, during this period the virus is still replicating at a high level.

Blood, semen, cervical secretions, and breast milk;

CSF, urine, saliva and tears are low risk.

Fusion,

Reverse Transcription (NRTI and NNRTIs),

Integration,

Proteases (maturity)

The first combination, once a day AIDs treatment;

3 drug combo of efavirenz, emtricitabine and tenofovir.

Causitive agents: Malassezia Furfur (tinea versicolor), Exophiala werneckii (tinea nigra), blac and white piedra;

;

Sx: do not cause inflammation!
Piedra infx cause development of nodules of asci on hair shafts.

Piedra and tinea cause hyper and hypopigmented spots on the skin.

Infants and the IC can develop fungemia;

;

Tx: Selenium sulfide (topical dandruff shampoo), shaving effected area, topical azoles.

Superficial fungal infections

;

Tinea versicolor, tinea nigra, black and white piedra.

Superficial fungal infections

;

Tinea versicolor, tinea nigra, black and white piedra.

;

Show a Coppery Orange Fluorescence

Topical azole antifungals (topical imidazoles);

;

Tx tinea capitis (scalp) with Griseofulvin (which inhbitis the mitotic spindle);

;

Treatment of these is required for weeks to months as relapses are common.

FALSE;

Animal to person = more inflammation;

Person to person = less inflammation.

Sporothrix schenckii - Agent of subcutaneous fungal infection known as Sporotrichosis or "rose gardeners disease" (aslo seen in handlers of sphagnum moss and in ulcerous lesions of cats);

Pulmonary form seen in alcoholics;

;

Cigar-shaped yeast in sputum or lesions.

Subcutaneous fungal infection caused by sporothrix schenckii (dimorphic fungus);

;

Tx with Itraconazole or Amphotericin B + Potassium Iodide

They assume 2 different morphologies based on their location;

;

"Mold in the Cold, Yeast in the Beast"

;

Cutaneous fungal infections are monomorphic as they only assume the mold form.

Sx: Acute pulmonary infections ("Fungus Flu") that do not respond to antibiotics and can progress to chronic pulmonary issues or dissiminate;

;

Etiologic agents: Histoplasma, Coccidioides, Blastomyces, and Cryptococcus;

;

Treatment: is typically with Amphotericin B which punches a hole in the cell membrane,

Ketoconazole is also often used and Flucytosine is used in cryptococcal infections.

Histoplasmosis;

;

Found in soil/dirt/dust enriched with bat and bird droppings;

;

Is an intracellular yeast that resides within macrophages.

It is a monomorphic, heavily encapsulated yeast that can be cultured from the CSF and visualized using India Ink;

;

Note that india ink is insensitive and latex agglutination should be used to confirm as well as culture as Cryptococcus is a Urease Positive Yeast.

Aspergillus, Candida, Zygomycoses, and Pneumocystis jioveci;

;

Pneumocystis jioveci is a leading cause of death in AIDS patients.

Aspergillus Fumigatus;

Is also monomorphic (always in its fungal form);

;

A is for Asperigullus, Acute angles, and Amphotericin (used to tx aspergillus)

Nasal Congestion,

Meningitis,

MI and many other manifestations

On Sabouraud's agar - contains peptones and dextrose at pH 5.6;

Candida forms germ tubes if incubated @ 37 degrees in serum.

The IC, diabetics, obese pt, pregnant pt, IV drug users;

Infection occurs where skin touches skin and can lead to gastritis, sepsis and endocarditis (esp in the IC and IV Drug users)

Immunocomprimised patients and

Pt with DiGeorge's Syndrome

Nystatin (topical or oral polyene antifungal);

;

Nystatin + Amphotericin B for dissiminated infx;

;

Flucytosine (which inhibits DNA synth) and capsofugin could be used.

Zygomycoses are opportunistic fungi = Mucor, Rhizopus, Absidia;

;

Non-septate hyphae typically at 90 degree angles

;

Cause severe infections that lead to tissue necrosis and attacking of the brain (rhinocerebral form of mucor can be fatal, man without a face story).

Zygomycoses

;

Pt with leukemia are also succeptible to this infection.

;

Tx: Amphotericin and removal of all necrotic tissue.

Caused by Pneumocystis jiroveci infection (PneumoCystis Pneumonia, PCP);

Fever, shortness of breath, non-productive cough;

;

H;E stain of lung tissue shows honeycomb appearence, patchy infultrates on CXR;

;

Dx: silver-stained cysts on BAL;

;

Tx: Trimethoprim (inhibits DHFR)