Bacterial Infections Flashcards

1
Q

Catalase positive is (staph or strep); catalase negative is (staph or strep).

A
  • staph
  • strep
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2
Q

weakly acid-fast indicates which two microbes?

A
  • actinomyces
  • nocardia
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3
Q

which 2 gram-positive bacilli is an endospore-former?

A
  1. bacillus
  2. clostridium
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4
Q

Which gram-positive bacilli is non-endospore forming and regularly shaped?

A
  1. listeria
  2. erysipelothrix
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5
Q

Which 2 bacterial microbes infect the trachea?

tracheitis

A

S. aureus
B. pertussis

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6
Q

Which bacterial microbes cause abscesses?

A
  1. bacteriodes
  2. fusobacterium
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7
Q

Which bacterial microbes cause pneumonia?

A
  1. pneumoniae (S, K, M)
  2. H. influenza
  3. P. aeuginosa
  4. S. aureus
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8
Q

Which bacterial microbes are superantigens?

A

S. pyogenes
M. pneumoniae

(myocplasma)

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9
Q

How does S. pyogenes cause anergy

A

M protenes bind to MHC II –> stim T cells w/VB8 TCR sequences

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10
Q

Define quinsy

A

painful abscess around tonsils

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11
Q

Define Pastia’s lines

streptococcal pharyngitis

A

dark red lines in creases/skin folds

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11
Q

A

A

D

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12
Q

Acute rheumatic fever is caused by what?

3 weeks post strep pyogenes infection

A

Antibodies to s. pyogenes that mimic epitopes on human collagen

complication of s. pyogenes

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13
Q

How do you distinguish moraxella catarrhalis from Neisseria

gram - diplococci, fastidious

A

moraxella has a butyrate esterase

tributyrin positive (right image: clearing)

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14
Q

which bacterial microbe causes “walking pneumonia”?

A

M. pneumoniae

mycoplasma

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15
Q

mycoplasma pneumonia key clues

A
  1. no cell wall
  2. walking pneumonia
  3. cold agglutinins
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16
Q

Damage from Mtb is caused by what?

A

your immune system

no toxins involved

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17
Q

Which bacterial microbe causes yellow-colored conolines in the presence of light?

A

mycobacterium kansasii

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18
Q

Where is mycobacterium kansasii typically seen?

geographic location

A
  1. ilinois
  2. oklahoma
  3. texas

(similar in presentation, dx testing and tx)

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19
Q

How does legionella pneumophila infect cells?

A

lodge in alveoli => phagocytosed by MF => MF invasion potentiator (Mip) => multiplies => released when MF dies

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20
Q
A

L. pneumophila

buffered charcoal yeast agar

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21
Q

What distinguishes legionella in laboratry testing?

A

BYE

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22
Q

Since chlamydia pneumoniae is grown in cells, how do you test for it (2)?

A
  1. PCR
  2. immunofluoresence
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23
Q

Chlamypsittacidia psittaci is an obligate intracellular bacteria. What is the active and inactive form?

A

elementary = infectious
reticulate = reproductive form (binary fission)

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24
Q

What distinguishes C. psittaci from other respiratory pathogens?

A

disseminates to spleen and liver

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25
Q

Tx for C. psittaci

A

doxycycline

26
Q

Key virulence factor for yersinia pestis?

A

Yops: impair phagocytosis

27
Q

Y. pestis forms which type of appearance on gram stain?

A

bipolar gram staining (“safety pin”)

28
Q

3 forms of y. pestis

A
  1. 2 inter-related
  2. epidemiologic cycles
  3. sylvatic
29
Q

Why is it concerning when Y.pestis gets into the lungs?

A

it is now transmissible to other people

(potential bioweapon; death within days)

30
Q
A

Actinomycetes nocardia

31
Q

How do you catch nocardia?

A
  1. inhalation of aerosolized particles
  2. open wound

(NOT person-person)

32
Q

How does Nocardia evade phacocytosis?

A
  1. disrupts acidification of phagosomes
  2. resisting oxidative burst
33
Q

mycoplasma pneumonia distinguishing symptoms

A

dry cough for months

34
Q
A

Strep throat

35
Q

What is the difference between scarlet fever and rheumatic fever?

A

scarlet = infected w/s.pyogenes that has been infected by bacteriophage
rheumatic = complication of strep throat

36
Q

Both scarlet & rheumatic fever present with rashes. How are they different?

A

scarlet = sandpaper-like
rheumatic = pink splotches (erythema marginatum)

37
Q

scarlet fever presentation

A
  1. strawberry tongue
  2. sand paper-like rash
  3. pastia’s lines
38
Q

Which bacterial microbe has LPS and OMV (outer membrane vesicles) as virulence factors?

A

M. Catarrhalis

(OMVs bud out and carry B-lactamase, LPS, adhesins)

39
Q

Which 2 microbes have a “fried egg” appearance?

A
  1. Y. Pestis
  2. M. Catarrhalis
40
Q
A

Mycoplasma pneumonia

note “fried egg” appearance

41
Q

Why does mycoplasma pneumoniae present with a dry cough?

A

mucociliary escalator inihibited

P1 adhesion molecule binds to sialic acid on epithelial cells

42
Q

Which bacterial microbe releases ROS (reactive oxygen species), leading to inflammation and damage to host cells?

hydrogen peroxide & superoxide

A

Mycoplasm

43
Q

Which 2 bacterial infection may require surgical excision?

A

m. avium
m. scrofulaceum

both form yellow colonies in light or dark w/in 2 weeks

44
Q

Which symptoms distinguish M. *avium-intracellular *complex from M. tb?

A

diarrhea (other symptoms are the same as Mtb: night sweats, weight loss, f/c

(legionalla also causes diarrhea)

45
Q

M. avium intracellular complex is diagnosed by which 3 tests?

A
  1. blood culture
  2. DNA probes
  3. PPD negative (Mtb is positive)
46
Q

Which 3 bacterial microbes cause respiratory disease that is mostly seen in children?

A
  1. M. pneumoniae
  2. M. scrofulaceum
  3. S. pyogenes (scarlet)
47
Q

Which bacterial microbe causes cervical lyph node enlargement that is painless but may ulcerate?

A

M. Scrofulaceum

48
Q

What is the best way to dx Legionella pneumophila?

A

direct fluorescent antibody smears + infected tissue

must acquire via bx or broncheolalveolar lavage (not in sputum)

49
Q

Which species of Chlamydia infect the respiratory tract?

trachomatis = genital

A
  1. psittaci
  2. pneumoniae
50
Q

Which 2 bacterial microbes cause “walking pneumonia”?

A
  1. mycoplasma pneumoniae
  2. chlamydia pneumoniae
51
Q

Describe the course of symptomatic C. pneumoniae infection

most cases are asymptomatic (walking pneumonia)

A

pharyngitis/laryngitis, followed by pneumonia/bronchitis 3 weeks later

cough persists for weeks

52
Q

Chlamypsittacidia psittaci is aka

A

parrott fever

53
Q

Chlamypsittacidia psittaci (aka parrot fever) s/sx

A
  1. flu-like sx
  2. hepatosplenomegaly

(dry cough, muscle ache, f/c, HA)

bird are asymptomatic

54
Q

Chlamypsittacidia psittaci (aka parrot fever) transmission

A

inhaling excreta (dust or secretions) of birds (close contact w/birds)

linked to cat or livestock resevoir

55
Q

Chlamypsittacidia psittaci pathogenesis

A

focal necrosis of liver and spleen –> disseminate to lungs –> edema –> mucous plugging of small airways

(can lead to anoxia)

56
Q

C. psittaci dx

A
  1. complement fixation = 4 fold
  2. immunofluorescence microscopy confirms
57
Q

Prevention of C. psittaci

A

tx infected imported birds w/chlortetracyline hydrochloride

58
Q

What are the key clues to Y. Pestis (black plague) virulence

A

YOPs

yersinia outer-membrane proteins

plasmid encodes type III secretion system

59
Q

Describe the colonies of Y. pestis

A

grey-white or yellow and opaque; “fried egg” appearance

60
Q

3 forms of Y. pestis

A
  1. urban (fleas/rats)
  2. sylvatic (fleas/prairy dog)

urban –> transmitted by respiratory droplets

61
Q

What is the main difference between bubonic plague and pneumonic plague presentation?

both cause pneumonia

A

bubonic plague: internal organ hemmorhage + buboes

62
Q

What is the difference between bubonic and pneumonic plague transmission

A

pneumonic: y. pestis person-person respiratory droplets
bubonic: flea bite (also transmitted to others through droplets)