Micro - Clinical Bacteriology (Gram + Branching Filaments & Mycobacterium) Flashcards Preview

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Flashcards in Micro - Clinical Bacteriology (Gram + Branching Filaments & Mycobacterium) Deck (43):
1

What are the Gram positive branching filament bacteria? What do they resemble?

(1) Actinomyces (2) Nocardia; Fungi

2

For Actinomcyes and Nocardia, which is each of the following: (1) Anaerobe (2) Aerobe (3) Acid Fast (4) Non acid fast?

(1) Actinomyces (2) Nocardia (3) Nocardia (4) Actinomyces

3

Where is Actinomyces found? Where is Nocardia found?

Normal oral flora; Found in soil

4

What signs/symptoms should you associate with Actinomyces?

(1) Oral/facial abscesses that drain through sinus tracts (2) Forms yellow "sulfur granules"

5

What signs/symptoms should you associate with Nocardia?

(1) Pulmonary infections in immunocompromised (2) Cutaneous infections after trauma in immunocompetent

6

How does Nocardia affect immunocompromised versus immunocompetent patients?

Immunocompromised = Pulmonary infections; Immunocompetent = Cutaneous infections after trauma

7

How do you treat Actinomyces?

Penicillin

8

How do you treat Nocardia?

Sulfonamides

9

In what context/case(s) would a patient have a PPD+?

If current infection, past exposure, or BCG vaccinated

10

In what context/case(s) would a patient have a PPD-?

If no infection or anergic (steroids, malnutrition, immunocompromise) and in sarcoidosis

11

What are the two kinds of tuberculosis following infection? To which patient population does each apply?

(1) Primary tuberculosis - Nonimmune host (usually child) (2) Secondary tuberculosis - Partially immune hypersensitized host (usually adult) = Reinfection

12

What process/event leads to Secondary tuberculosis?

Reinfection

13

What finding(s) is/are associated with Primary tuberculosis?

Ghon complex = Hilar nodes + Ghon focus (usually in mid zone of lung)

14

What finding(s) is/are associated with Secondary tuberculosis?

Fibrocaseous cavitary lesion (usually upper lobes)

15

What other kind of tuberculosis results from reactivation tuberculosis of the lungs? What specific findings are associated with this?

Extrapulmonary tuberculosis: CNS (parenchymal tuberculoma or meningitis), Vertebral body (Pott's disease), Lymphadenitis, Renal, GI

16

What are 4 potential initial consequences of Primary tuberculosis?

(1) Heals by fibrosis (2) Progressive lung disease (HIV, malnutrition) (3) Severe bacteremia (4) Preallergic lymphatic or hematogenous dissemination

17

What is/are the significant outcome(s) when Primary tuberculosis heals by fibrosis?

Immunity and hypersensitivity --> Tuberculin positive

18

What is/are the significant outcome(s) when Primary tuberculosis leads to progressive lung disease? In what kind of patients is this likely to occur?

Death (rare); HIV, malnutrition

19

What is/are the significant outcome(s) when Primary tuberculosis leads to severe bacteremia?

Miliary tuberculosis --> Death

20

What is/are the significant outcome(s) when Primary tuberculosis leads to preallergic lymphatic or hematogenous dissemination?

Dormant tubercle bacilli in several organs --> Reactivation in adult life

21

Again, what are the 4 options for initial consequences of Primary tuberculosis? What are the outcomes associated with each?

(1) Heals by fibrosis --> Immunity and hypersensitivity --> Tuberculin positive (2) Progressive lung disease (HIV, malnutrition) --> Death (rare) (3) Severe bacteremia --> Miliary tuberculosis --> Death (4) Preallergic lymphatic or hematogenous dissemination --> Dormant tubercle bacilli in several organs --> Reactivation in adult life

22

What pathogen causes TB? What is important to know about its treatment?

Mycobacterium tuberculosis; Often resistant to multiple drugs

23

Which mycobacterium causes pulmonary TB-like symptoms?

M. kansasii

24

What mycobacterium causes disseminated, non-TB disease in AIDS? What is important to know about its treatment? What is its prophylactic treatment?

M. avium-intracellulare; Often resistant to multiple drugs; Azithromycin

25

What kind of organisms are all mycobacteria?

Acid-fast

26

Again, what pathogen causes TB? What are TB symptoms?

Mycobacterium tuberculosis; Fever, night sweats, weight loss, hemoptysis

27

Which mycobacteria are often resistant to multiple drugs?

(1) M. tuberculosis (2) M. avium-intracellulare

28

What kind of symptoms does M. kansasii cause?

Pulmonary TB-like symptoms

29

What kind disease does. M. avium-intracellulare cause, and in what patient population?

Causes disseminated, non-TB disease in AIDS (patients)

30

What 2 virulence factors are found in Mycobacteria?

(1) Cord factor (2) Sulfatides (surface glycolipids)

31

In what kind of bacteria is cord factor found? What is its mechanism?

Virulent strains of Mycobacteria; Inhibits macrophage maturation and induces release of TNF-alpha

32

In what kind of bacteria are sulfatides found? What is its mechanism?

Mycobacteria; Sulfatides (surface glycolipids) inhibit phagolysosomal function

33

What is another name for Leprosy? What pathogen causes it?

Hansen's disease; Mycobacterium leprae

34

How is M. leprae classified? What kind of temperatures does it like?

Acid-fast bacillus that likes cool temperatures

35

Again, what kind of temperatures does M. leprae like? What does it infect? What is the nickname of the condition that results?

Likes cool temperatures; Infects skin and superficial nerves - "glove and stocking" loss of sensation

36

What is important to know about M. leprae with regard to its lab studies?

Cannot be grown in vitro

37

What is the reservoir of M. leprae in the United States?

Armadillos

38

What is another name for Hansen's disease? What pathogen causes it? What are the 2 forms of Hansen's disease?

Leprosy; M. leprae; (1) Lepromatous (2) Tuberculoid

39

How does the Lepromatous form of Hansen's disease present? How is it characterized?

Presents diffusely over skin and is communicable; Characterized by low cell-mediated immunity with a humoral Th2 response

40

How does the Tuberculoid form of Hansen's disease present? How is it characterized?

Limited to a few hypoesthetic (reduced sense of touch), hairless skin plaques; Characterized by high cell-mediated immunity with a largely Th1-type immune response

41

Again, what are the 2 forms of Leprosy/Hansen's disease? What is the treatment for each of these forms?

(1) Lepromatous - Multidrug therapy consisting of Dapsone, Rifampin, and Clofazimine for 2-5 years (2) Tuberculoid - Multidrug therapy consisting of Dapsone and Rifampin for 6 months

42

Which form of Hansen's disease can be lethal?

Lepromatous; Think: LEpromatous can be LEthal

43

What test may be used as an alternative to PPD, and what is its advantage?

Interferon-gamma release assay (IGRA) is more specific test; has fewer false positives from BCG vaccination

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