MICR_041813 Leg_Coryne_Myco Flashcards

1
Q

What are some characteristics of legionella pneumophilia?

A

gram (-) pleiomorphic rod, intracellular growth, fastidious

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where is legionella pneumophilia normally found?

A

water of cooling towards, growing within AMOEBAS or BIOFILMS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Who is at risk for legionella pneumophilia?

A

elderly, immune-compromised or immuno-suppressed patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What symptoms does legionella pneumophilia cause?

A

ATYPICAL PNEUMONIA, fevers, chills, productive cough, muscle aches, headaches, loss of appetite, diarrhea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Infections with legionella pneumophilia can be severe or mild. What characterizes either form?

A

MILD: “pontiac disease” W.O pneumonia. SEVERE: can disseminate from the lungs and cause systemic damage due to LPS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What’s the difference between atypical and typical pneumonia?

A

ATYPICAL: diffuse infection in the lungs; does not respond to penicillin or sulfonamide. TYPICAL: lobar, localized infection in the lungs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What pathogens ause atypical pneumonia? Typical pneumonia?

A

ATYPICAL: legionella, mycoplasma, chylamdia. TYPICAL: Haemophilus influenza, Moraxella catarrhalis, Streptococcus pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is legionella pneumophilia usually acquired?

A

airborne from environemental contamination, NOT from infected people.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the pathogenicity mechanism of legionella pneumophilia?

A

1) acquired via airborne route, 2) incubation period 2-10d, 3) EARLY stage: apoptosis of macrophage and alveolar epithelial cells, 4) LATE stage: necrosis, 5) SEVERE: dissemination from lungs -> systemic disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is legionella pneumophilia diagnosed? (4)

A

1) since it’s fastidious, grow on charcoal yeast extract with iron/cysteine. 2) fluorescent antibody test to ID organism in sputum. 3) detect antigens in urine sample, 4) detect antibody levels in blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do you prevent legionella pneumophilia?

A

proper water handling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does mycoplasma pneumoniae cause?

A

infection of the respiratory tract in humans only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a cool fact about mycoplasma pneumoniae?

A

it’s the smallest replicating bacteria!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are some characteristics of mycoplasma pneumoniae?

A

no cell wall, gram variable, pleiomorphic shape, colonies have a fried egg appearance, one serotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does mycoplasma pneumoniae require for growth?

A

cholesterol - its usually obtained from the host or supplemented in the growth medium. Provides membrane rigidity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What enables mycoplasma pneumoniae to evade the immune response?

A

various lipoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which age group is most susceptible to mycoplasma pneumoniae?

A

school age kids - young adults; severity of infection is correlated with age

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

T/F Infection with mycoplasma pneumoniae provides life-long immunity.

A

False. Immunity is NOT lifelong

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the frequency of mycoplasma pneumoniae outbreaks?

A

4-8 year intervals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are hthe symptoms of mycoplasma pneumoniae?

A

ATYPICAL PNEUMONIA - gradual onset of non-productive cough -> sputum with small amounts of blood -> weakness, fever, cough, headache, diffuse changes on chest xray

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are some complications that can arise from mycoplasma pneumoniae infection?

A

extrapulmonary infections in CNS with additional symptoms (arthritis, autoimmune disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the mechanism of pathogenesis of mycoplasma pneumoniae?

A

1) aerosol droplet transmission, 2) attaches to epithelium via P1 adhesin, 3) production of H2O2 and superoxide, which causes oxidative damage to the cell, 4) inflammation, 5) disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the 3 virulence factors of mycoplasma pneumoniae?

A

1) P1 adhesin, 2) H2O2, 3) superoxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How do you diagnose mycoplasma pneumoniae? (4)

A

1) sputum gram stain 2) throat swab and culture, 3) PCR, 4) cold agglutination test

25
Q

What is cold agglutination? What organism is this test used to detect?

A

auto-agglutination of RBC at low temps due to the presence of auto-immune antibodies against RBCs

26
Q

How do you treat mycoplasma pneumoniae?

A

macrolides (erythromycin), tetracycline

27
Q

T/F The vaccine for mycoplasma pneumoniae is a live-attenuated one.

A

No such thing. There is no vaccine for mycoplasma pneumoniae!!

28
Q

What are some charcteristics of cornynebacterium diphtheriae?

A

gram (+), pleiomorphic, aerobe, does not form spores

29
Q

What are the two groups of cornynebacterium diphtheriae?

A

1) cornynebacterium diphtheriae - cause of diphtheriae 2) diphtheroids (all others) - normal commensal bacteria

30
Q

Where is cornynebacterium diphtheriae most prevalent?

A

developing countries with inadequate pediatric immunizations/medical care

31
Q

T/F Infection with cornynebacterium diphtheriae provides life-long immunity.

A

False. Immunity is NOT lifelong

32
Q

What is the mechanism of pathogenesis of cornynebacterium diphtheriae?

A

1) aerosol droplet transmission, 2) attaches to epithelium in the throat or skin. THROAT: fever, sore throat, pseudomembrane formation. SKIN: necrotizing skin

33
Q

What is the pseudomembrane made of? What bacteria produces it?

A

produced by cornynebacterium diphtheriae. Made of fibrin, necrotic epithelium, WBC

34
Q

T/F cornynebacterium diphtheriae can cause systemic disease.

A

False. It is confined to the initial infection site (throat/skin)

35
Q

If cornynebacterium diphtheriae is confined to the initial infection site, what causes the systemic symptoms observed?

A

Diphtheria toxin (produced by cornynebacterium diphtheriae in the throat)

36
Q

What does diphtheria toxin do?

A

it’s lethal to cells of the heart, kidneys, and nervous system. BLOCKS PROTEIN SYNTHESIS by inactivating elongation factor 2 (EF2) - an enzyme involved in peptide bond formation on ribosomes

37
Q

How do you diagnose cornynebacterium diphtheriae? (5)

A

1) presence of pseudomembrane, 2) grow on special media (tellurite agar, tinsdale medium, loeffler media) and look for metachromatic granules, 3) PCR, 4) Immunoassay, 5) Elek Test

38
Q

What is the Elek test? What is it used to diagnose?

A

used to determine if the suspected strain of cornynebacterium diphtheriae is toxigenic – if it is, a toxin/anti-toxin band is observed

39
Q

How do you treat cornynebacterium diphtheriae? (2).

A

antitoxin for horse (neutralizes the free toxin) and penicillin

40
Q

How do you treat people who’s been in contact with patients infected with cornynebacterium diphtheriae?

A

reimmunization + penicillin

41
Q

What vaccine is available for cornynebacterium diphtheriae?

A

formaldehyde-treated diphtheria toxin = TOXOID, which is coupled with pertussis + tetanus vaccine (DTaP)

42
Q

What does the bordetella pertussis use to attach to lung epithelium? (4)

A

1) pili, 2) filamentous hemagglutinin (FHa), 3) pertactin, 4) trachael colonization factor

43
Q

T/F immunization with DTaP provides lifelong immunity.

A

False. It does not confer life-long immunity

44
Q

What is the difference between DTP and DTaP?

A

both are trivalent vaccines, but DTP can cause encephalopathy and permanent neurological sequelae. DTaP contains acellular pertussis and avoids problems observed with DTP

45
Q

How would you diagnose bordetella pertussis?

A

Using nasopharyngeal swabs, use 1) PCR, 2) culture test, 3) antibody test

46
Q

How would you treat bordetella pertussis?

A

Erythromycin, Tetracycline, Chloramphenicol

47
Q

What are the virulence determinants of proteus vulgaris/proteus mirabilis? (2)

A

flagella (“swarming” motility) and urease

48
Q

Why is urease production importance in the pathogenicity of proteus vulgaris/proteus mirabilis?

A

it converts urea into ammonia, which increases the pH/alkalinity of the urine, leading to an increase in chronic UTI

49
Q

Where is acinetobacteria normally found?

A

opportunistic infection in hospitalized patients, often associated with use of indwelling medical devices (IVs, grafts)

50
Q

What are the virulence factors of acinetobacteria?

A

capsule, adhesins, proteolytic and lipolytic enzymes

51
Q

What is characteristic of acinetobacteria that cause opportunistic infections?

A

multi-drug resistant strains are increasing

52
Q

How can you diagnose gram (-) pathogens? (3)

A

colony morphology, selective medium, and biochemical tests.

53
Q

Which gram (-) pathogens are facultative anaerobes?

A

1) proteus mirabilis, 2) e. coli, 3) enterobacter cloacae, 4) klebsiella pneumonia, 3) serratia marcesens (THINK: facultative anaerobe PEEKS out every once in a while for air)

54
Q

Which two gram (-) pathogens are aerobes?

A

1) acinetobacteria, 2) pseudomonas aeruginosa (THINK: aerobes Prefer Air)

55
Q

Which 3 gram (-) pathogens are lactose fermenters?

A

1) e. coli, 2) klebsiella pneumonia, 3) enterobacter cloacae

56
Q

How can Shigella be prevented?

A

better sanitation

57
Q

What is the Kigler Iron Agar test?

A

biochemical test that detects sugar (glucose, lactose) fermentation and gas (H2S) production

58
Q

How do you intepret a Kigler Iron Agar test?

A

Yellow Slant = fermented lactose. Yellow BUTT = fermented glucose. BLACK PPT = H2S production.