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Microbiology Part 2 > Lec46 Opportunistic Infections > Flashcards

Lec46 Opportunistic Infections Flashcards

1
Q

What are opportunistic pathogens?

A
  • lack intrinsic virulence

- almost exclusively cause disease in individual with impaired host defense

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2
Q

What are principal pathogens?

A
  • have intrinsic virulence and cause regular disease in pts immunocompetent
  • occur with more frequency/severity in pts with impaired host defense
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3
Q

What are you at more risk for with defect in cell mediated immunity?

A

viral pathogens

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4
Q

What are you at more risk for with defect in neutrophils?

A

bacterial and fungal infections

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5
Q

How do you measure severity of neutropenia?

A

absolute neutrophil count

= WBC * (%neutrophils + %bands)

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6
Q

How do you restore immune function in neutropenic pt?

A
  • use GCSF or other growth factor
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7
Q

What are four different stains used for pneumocystis and what do they stain?

A

GMS stain: cyst forms in bronchioalveolar lavage
Wright-Giemsa stain: stains trophic forms in foamy exudate
Calcofluor white: stains fungal cyst wall
DFA: shows cysts sand trophic forms

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8
Q

What are two diseases to look out for in pt with CD4 < 50?

A
  • disseminated mycobacterium avium complex

- cytomegalovirus

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9
Q

When does HIV pt start to have high risk of PCP pneumonia?

A

at CD4 < 200

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10
Q

Pt with low CD4 and hypoxemia what should you think?

A

PCP pneumonia

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11
Q

What stain to find mycobacterium avium complex?

A

AFB stain

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12
Q

What are symptoms of MAC?

A

disseminated diseased in AIDS characterized by: bacteremia, fever/chills/sweat/weight loos/diarrhe, bone marrow suppress [anemia, low WBC]

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13
Q

How do you diagnose MAC?

A

use of special blood culture bottles and can take wks

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14
Q

How do you prevent MAC [mycobacterium avium complex]? Treat?

A

prevent: azithromycin prophylaxis
treat: 2-3 drug combo and restoration CD4

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15
Q

Fever/headache then seizure + ring enhancing lesions in brain with AIDS? What should you think?

A

cerebral toxoplasmosis

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16
Q

Fever/headache then seizure without enhancing lesions in brain with AIDS? What should you think?

A

cryptococcus neoformans [cryptococcus meningitis]

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17
Q

What are clinical findings of JC virus?

A
  • no disease in immunocompetent
    in AIDS: enters through resp tract and latent in kidney, reactivation –> viremia and infection of oligodendrocytes –> demyelinating disease
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18
Q

How is JC virus transmitted?

A

via respiratory tract

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19
Q

What is treatment for JC virus?

A

no treatment, poor prognosis

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20
Q

What are characteristics of JC virus?

A
  • polyoma virus, non enveloped dsDNA virus, ubiquitous
21
Q

What is HIV prophylaxis for pulm TB? when do you give it?

A
  • give isoniazid for 9 mos in pt with latent TB

- at any CD4 count

22
Q

What is neutropenia definition?

A

ANC < 500

23
Q

What is HIV prophylaxis for PCP pneumonia? when do you give?

A
  • TMP/SMX

- give when CD4 < 200

24
Q

What is HIV prophylaxis for CNS toxoplasmosis? when do you give?

A
  • TMP/SMX

- for pt with seropositive toxoplasma with CD4 < 100

25
Q

What is HIV prophylaxis for disseminated mycobacterium avium complex? when do you give?

A
  • azithromycin

- when CD4 < 50

26
Q

What 2 kinds of infections do you see at < 1 month after solid organ transplant?

A
  • bacterial surgical site infection

- nosocomial infections

27
Q

What kinds of infections do you see at 1-12 month after solid organ transplant?

A

PCP, CMV/EBV/HSV/VZV, listeria, noardia, toxoplasma, strongyloides, community acquired

28
Q

What 2 kinds of infections do you see at >6-12 months after solid organ transplant?

A
  • community acquired infections

- EBV

29
Q

If you are treated for rejection after transplant what happens to risk of diseases?

A
  • reset clock, at risk for the same diseases you were when you first got transplant [bacterial surgical site infection, nosocomial]
30
Q

What is most common classic opportunistic infection in HIV?

A

PCP

31
Q

What is prophylaxis for PCP in solid organ transplant recipient?

A
  • TMP-SMX prophylaxis during period of high immunosuppression
32
Q

What is prophylaxis for CMV in solid organ transplant recipient?

A
  • prophylaxis: ganciclovir or valgancyclovir x 3-6 mos for all recipient
  • preemtion: monitor CMV PCR frequently, if PCR + start ganciclovir and decrease immunosuppression
33
Q

What is prophylaxis for EBV in solid organ transplant recipient?

A
  • monitor EBV pcr frequently, if + decrease immunosuppression
34
Q

What is definitiona of neutropenia?

A

ANC < 500 cells/mm

35
Q

What are major pathogens associated with neutropenia?

A
  • gram negative bacteria [pseudomonas]
  • candida
  • aspergillus and other filamentous fungi –> esp with long duration of neutropenia
36
Q

What do you do with pt with fever and neutropenia following chemo?

A
  • initiate broad spectrum antibiotic with activity against pseudomonas [ex cefepime]
  • also can add: vancomycin for MRSA, aminolgycoside for gram neg, fluconazole for candida
  • if prolonged neutropenia –> give voriconazole in case of aspergillus
37
Q

What are risk factors for infection following bone marrow transplant?

A
  • neutropenia in pre-engraftment period –> get bacteria/fungi
  • immunosuppressants to prevent graft vs host –> see pathogens similar to those after solid organ transplant
38
Q

What are possible causes of hematuria in pt with acute myeloid leukemia on treatment? [2 viruses]

A
  • due to radiation therapy, chemotherapy

- due to infection: adenovirus, BK virus

39
Q

What are characteristics of BK virus?

A
  • ubiquitous, polyoma virus
40
Q

What are clinical syndromes associated with BK virus?

A
  • hemorrhagic cystitis following BMT

- hemorrhagic cystitis and renal graft loss following kidney transplant

41
Q

What treatment for BK virus?

A
  • no effective therapy, can use cidofovir

- critical to decrease immunosuppression

42
Q

what are differences nocardia and actinomyces?

A

both: gram + rods, branching filamentous, slow-growing
nocardia: strictly aerobic, weak acid fast
actinomyces: facultative anaerobic, not acid fast

43
Q

Toxoplasma transmission?

A
  • parasite, host in nature is cats

- humans infected by cat stool –> contaminated by pet cat fecal oral, or via cow/pig meat that can be infected

44
Q

What type of infections common in person with antibody deficiencies [ex hypogammaglobulinemia]?

A
  • recurrent serious bacterial infections
  • chronic enteroviral infections
  • chronic diarrhea
45
Q

what types of infections common in person with disorder of phagocytic function [chronic granulomatous disease]?

A
  • s. aureus, burkholderia cepacia, nocardia candida, aspergillus
46
Q

what type of infection occurs in person with T cell lymphocyte deficiency [SCID]?

A
  • PCP
47
Q

what type of infection occurs in person with hyper IgE?

A

recurrent severe Staph Aureus infections

48
Q

what type of infection occurs in person with terminal complement deficiency?

A

recurrent neisseria meningitidis infection

Microbiology Part 2 (30 decks)

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