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Flashcards in Opportunistic Infx Deck (44)
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list the 3 types of defects in the compromised host and give an example of each ?

1- defects or injury to physical barrier
ex- serious burns
2- deficiency in innate immunity
ex- reduced # or function of PMN (leukemia, chemotherapy, cong. immune def.)
3- deficiency in adaptive immunity
ex- t cells (HIV/AIDS) ; B cell and Ab (congen. immune def)


What organisms are the MCC of burn infections (4) which of these are on skin?

Pseudomonas, Staph aureus (skin), Strep (skin), Candida (skin)


Where is psuedomonas likely to grow within a hospital?

In moist/ wet areas : sinks etc,


In the case of a servere burn patient what factors increase risk of infection?

1- burn itself- loss of protective skin
2- severe burns decrease in PMN function
3- hospitalization- at risk for nosocomial infection


Where could aspergillus be found in a hospital?

potted plants (soil) , air ducts etc. transmitted to skin via spores


A serverely burned child has multiple nosocomial infections one of which is aspergillus- what is the preferred treatment and what are possible side effects

amphotericin - TOXIC TO KIDNEYS


list several possible drug treatments for a pseudomonas infection

extended spectrum PCN +/- beta-lactamase inhibitors; carbapenems, aztreonam, fluoroquinolones, ceftazidime, cefepime, aminoglycoside


what are ways a neonate can become infected with Listeria from the mother?

transplacental transmission
ascending infx through ruptured amniotic membranes
during birth through infx birth canal


what is the DOC for infant with Listeria infx?

Ampicillin + Gentamycin


what is the DOC for mother if showing sx of Listeria



severe asthmatic patient dx with pneumonia. the origin is Nocardia sp. - what made this patient suceptible to this infx?

long term cortico steroid therapy !!!!


What are common sources of nocardia bacteria?



What are some KEY buzzwords/characteristics regarding Nocardia?

aerobic, G+ bacilli tends to form CHAINS OR FILAMENTS, weakly acid fast


What is the DOC for Nocardia infx?

TMP/SMX - folic acid inhibitor


Pt w/ h/o AIDS presents w/ fever, night sweats, fatigue, diarrhea past 3 mo. Dx Mycobacterium avium. GROWING IN MACROPHAGES-
A- how would it be killed?
B- where does it come from?

A- normally T cells will kill infx Macrophages
B- soil


When T cell count gets below 50 in AIDS pt what is DOC for Mycobacterium avium tx? CAN USE EVEN AS PREVENTION!

Macrolide + Ethambutol


What are some causes of neurologic signs in AIDS patient suspect???

AIDS dementia; Toxoplasmosis; EBV- B cell lymphoma; CMV; Coccidiodes/ Cryptococcus; JCV (polyoma virus)


AIDS pt c/o slow onset of progressive confusion/forgetful past 6 weeks; develops hemiparesis on one side of body. CSF fluid PCR dx JCV. What is the dz caused by this

PML - progressive multifocal leukoencephalopathy


What are sx of PML associated with JCV

slow onset of focal sx includes behavior/speech/cognitive behavior/motor/visual impairment; aphasia, hemiparesis, ataxia, cortical blindness,


how can you make a definitive dx of PML due to JCV

PCR of CSF sample


23 y/o AIDS pt develops fever, nuchal rigidity, severe HA - what is the MCC of meningitis in AIDS pt? What is one of the virulence factors associated with this organism

Crytococcus meningitis - CAPSULE


Where is Cryptococcus meningitis commonly found?

soil- bird droppings


What is missing in the immune response why AIDS pt gets cryptococcus

macrophage cant be activated bc T cell counts very low and if no T cells no IFN-gamma to activate Macrophage!


How would you diagnose cryptococcus ?

India Ink stain CSF- yeast w/ capsule
Confirm with growth on Sabouraud's agar, Heart Brain infusion agar


How would you treat cryptococcus in AIDS pt ?

Amphotericin B and flucytosine


AIDS pt from SE Missouri, presents w/ persistent high grade fever, weight loss, hepatosplenomegaly, mucocutaneous ulcers. You perform ELISA on serum and urine for antigen was +
A- Whats the source of infection?

A- spores inhaled


What would histoplasma infection look like on CXR in an immunocompetent pt

walled off (granulomas present)


What T cell is needed for granuloma formation/ chronic inflammation? what happens when a pt with granulomas develops AIDS

Th1 cells - no T cell response so dissemination


Who is at risk for H. capsulatum ? What would be the immunocompetent pt immune response?

ANYONE that is in MS river valley area/ frequently goes caving etc.
Th1 involved/ Macrophage involved in forming granuloma wall the infection off


What is the DOC/tx for H. capsulatum ?

Amphotericin B +/- azole