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MSK Test 1 > LEC-7 Zoonotic Bacterial Infections > Flashcards

LEC-7 Zoonotic Bacterial Infections Flashcards

1
Q

What is Brucella?

A
  • A bacterial genus that, upon infection, causes Brucellosis with the following signs/symptoms:
    • Fever, malaise, fatigue/weakness, headache, myalgias, anorexia leading to weight loss, granulomas, and a non-productive cough
    • Also causes GI provlems such as nausea and vomiting (up to 70% of patients)
  • Slow pathogenesis with a course of a few weeks
  • Diagnosis is made with proper history (since bacteria is closely associated with animals such as sheep, goats, cattle, and swine)
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2
Q

What are the characteristics of Brucella?

A
  • Gram-negative (G-) coccobacilli
  • Facultative intracellular pathogen (good for survival in human cells; prefers macrophages)
  • Aerobic
  • Catalase +
  • Oxidase +
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3
Q

Chronic brucellosis is associated with ______________.

A

Depression

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4
Q

Brucella is Gram-(positive/negative).

A

Negative

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5
Q

Brucella is a (bacillus/coccus/coccobacillus/spirillum).

A

Coccobacillus

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6
Q

Brucella is catalase (positive/negative).

A

Catalase positive

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7
Q

Brucella is oxidase (positive/negative).

A

Oxidase positive

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8
Q

(T/F) Brucella is a facultative intracellular parasite.

A

True.

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9
Q

What media is used to culture Brucella?

A

Blood agar OR chocolate agar

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10
Q

Addition of _____________ enhances the growth of Brucella in cell culture.

A

Erythritol

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11
Q

Brucella incubates (slowly/quickly).

A

Slowly

  • 21-35 days
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12
Q

What are the primary pathogens of Brucella?

A
  • Endotoxin (LPS)
  • AMP and GMP
  • Superoxide dismutase
  • Type IV secretion system
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13
Q

What is the mechanism by which the Type IV secretion system is pathenogenic in Brucella?

A

Inhibits phagolysosome fusion (Brucella injects it’s protein ino macrophages like a syringe)

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14
Q

What is the mechanism by which AMP and GMP are pathenogenic in Brucella?

A

Inhibits bacterial myloperoxidase-halide system in phagocytes (prevents phagocyte from killing bacterium)

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15
Q

What is the mechanism by which superoxide dismutase is pathenogenic in Brucella?

A

Inhibits oxidative destruction of the bacterium

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16
Q

What is the major virulence determinant in Bruccella and what are the two types?

A
  • Endotoxin (LPS)
  • Two types:
    • Smooth LPS (virulent)
    • Rough LPS (avirulent)
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17
Q

The (smooth/rough) LPS of Brucella is relatively non-virulent as it is susceptible to lysis by normal serum.

A

Rough

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18
Q

The (smooth/rough) LPS of Brucella is extremely virulent, avoiding the lysosome and surrounding itself with the cell’s ER.

A

Smooth

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19
Q

Part of the body’s defense against Brucella is the formation of ____________.

A

Granulomas

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20
Q

What is the typical pathogenesis for Brucella?

A
  1. Entry (causes abscess)
  2. Survival within macrophages
  3. Entry into lymphatics
  4. Draining lymph nodes
  5. Entry into blood stream and bacteremia
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21
Q

What are the most common sites affected by systemic spread of Brucella?

A
  • Liver
  • Spleen
  • Lymph nodes
  • Bone marrow
  • Kidneys
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22
Q

Chronic Brucellosis may result in __________________ within the bone, liver, and kidney.

A

Suppurative (pyogenic) lesions

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23
Q

Persistent elevation of which immunoglobulin is prognostic of a chronic Brucella infection?

A

IgG

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24
Q

In serological diagnosis of Brucella, physicians should watch for a ___-fold rise in antibody titer, or a titer greater than ___.

A

4-fold rise in titer titer greater than 160

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25
Q

In what ways is Brucella transmitted from animals to humans?

A
  • Direct contact with cuts or abrasion on skin
  • Secretion (milk, urine, placental tissue) contact with human wound
  • Inhalation of aerosols
  • Unpasteurized dairy products or contaminated meat
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26
Q

Human to human transmission of Brucella is (rare/common).

A

Rare

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27
Q

What are common high risk occupations for Brucella infection?

A
  • Slaughterhouse work
  • Meat inspectors
  • Veterinarians
  • Ranchers
  • Laboratory personnel
28
Q

There are approximately ___ cases of Brucella infection per year in the U.S.

A

100

29
Q

What is the primary treatment of Brucellosis?

A
  • Doxycycline (tetracycline - inhibits 30S ribosomal subunit)

AND

  • Streptomycin (aminoglycoside - inhibits 30S ribosomal subunit)/ OR
  • Rifampin (inhibits bacterial RNA polymerase)
30
Q

There (is/is not) a vaccine available for Brucella.

A

Is NOT

31
Q

_______________ is a diverse group of small, aerobic, Gram-negative bacilli that are fastidious and slow-growing in specialized media. 3 of its 19 species are able to infect humans.

A

Bartonella

32
Q

Bartonella is Gram-(negative/positive).

A

Negative (G-)

33
Q

Bartonella is a (bacillus/coccus/coccobacillus/spirillum).

A

Bacillus

34
Q

Bartonella (quintana/henselae/bacilliformis) causes Trench fever and bacillary angiomatosis. It is spread from human to human by infected lice.

A

Bartonella quintana

35
Q

Bartonella (quintana/henselae/bacilliformis) causes Oroya fever and Verruga Peruana. It is transmitted by the sand fly, but remains localized to Central and South America.

A

Bartonella bacilliformis

36
Q

Bartonella (quintana/henselae/bacilliformis) causes cat-scratch disease. Cats serve as a reservoir for this bacteria and may transmit infection via bites, scratches, or fleas.

A

Bartonella henselae

37
Q

____________ is characterized by mild, relapsing fever, sudden onset of chills, headache, and maculopapular rash on the trunk and abdomen. Its symptoms last 14-30 days and it is diagnosed by serology or PCR analysis. It is more common in alcoholics and the homeless, being transmitted by lice.

A

Trench fever

  • Bartonella quintana
38
Q

What is the primary treatment for Trench fever caused by Bartonella quintana?

A

Doxycycline (tetracycline - inhibits 30S ribosomal subunit)

39
Q

__________ occurs at a rate of 24,000 cases per year in the U.S. It is characterized by benign, tender lymphadenopathy that may become suppurative, erythematous papule at site of scratch, skin or eye rash, and in rare cases, hepatosplenomegaly. It is primarily spread by domestic or stray cat and is most common in children or young adults.

A

Cat Scratch Disease

  • Bartonella henselae
40
Q

The ___________ is the most common site of lymphadenopathy in patients with Cat Scratch Disease caused by Bartonella henselae.

A

Axilla

41
Q

What are the primary methods of confirming Bartonella henselae in a patient suspected of Cat Scratch Disease?

A
  • Proper history (hx of cat or flea contact or scratches)
  • PCR analysis
  • Serology
  • Biopsy of node, skin, liver, or bone marrow showing granulomatous inflammation
    • Positive Warthin-Starry silver stain
42
Q

What is the primary treatment for Cat Scratch Disease caused by Bartonella henselae?

A
  • Azithromycin (macrolide - inhibits 50S ribosomal subunit) for uncomplicated
  • Doxycycline (tetracyclines; MOA - inhibits 30S ribosomal subunit)
  • Erythromycin (macrolide - inhibits 50S ribosomal subunit)

Rifampin (inhibits bacterial RNA polymerase) in combination with doxycycline for sever cases

43
Q

All Bartonella may infect endothelial cells and induce angiogenesis, but the most likely species are Bartonella __________ and __________.

A

B. quintana and B. henselae

44
Q

_______________ is a condition in which lesions are characterized by endothelial cell proliferation, inhibition of endothelial cell apoptosis, and increased secretion of vasoproliferative cytokines. It is most often seen in immunocompromised patients with lesions resembling Kaposi sarcomas. Bacterial identification is made by PCR or cell culture.

A

Bacillary angiomatosis

  • Caused by B. quintana or B. henselae
45
Q

What is the primary treatment for bacillary angiomatosis caused by B. quintana or B. henselae?

A
  • Erythromycin (macrolide - inhibits 50S ribosomal subunit)

OR

  • Doxycycline (tetracycline - inhibits 30S ribosomal subunit)
46
Q

(Oroya fever/Verruga peruana) is characterized by acute febrile anemia. It is caused by B. _____________.

A

Oroya fever B. bacilliformis

47
Q

(Oroya fever/Verruga peruana) is characterized by angioprolific cutaneous disease resembling bacillary angiomatosis. It is caused by B. _____________.

A
  • Verruga peruana
  • B. bacilliformis
48
Q

______________ is a Gram-negative coccobacillus that displays bipolar staining with methylene blue, a positive result on both the catalase and oxidase test, and is found as a commensal or pathogen in the nasopharynx of wild and domestic dogs, cats, and other animals.

A

Pasteurella

49
Q

Most human infections by Pasteurella are caused by Pasteurella ___________.

A

P. multocida

50
Q

What are the primary virulence factors associated with Pasteurella?

A
  • LPS (endotoxin)
  • Neuraminidase
  • Capsule (carbohydrate)
51
Q

Pasteurella is Gram-(positive/negative).

A

Gram-negative

52
Q

Pasteurella is a (bacillus/coccus/coccobacillus/spirillum).

A

Coccobacillus

53
Q

Pasteurella is catalase (positive/negative).

A

Catalase positive

54
Q

Pasteurella is oxidase (positive/negative).

A

Oxidase positive

55
Q

Pasteurella grows (slow/fast) in lab culture.

A

Fast

56
Q

Human infection by Pasteurella is most commonly associated with (bite/scratch) wounds.

A

Bite

  • Pasteurella is localized to the nasopharynx of animals
57
Q

Infection by _____________ causes abscess, localized cellulitis, and lymphadenopathy within 24h (rapid). Once bacteremia is achieved, microabscesses and/or hemorrhagic lesions in the lungs, joints, bone, and other organs result. Focal soft tissue infection, pain, swelling, and erythema may also result. In rare cases, osteomyelitis or, in older individuals, chronic respiratory infection or septic arthritis may occur.

A

Pasteurella multocida

58
Q

What is the primary method for diagnosis of Pasteurella multicoda?

A
  • Cell culture
  • Proper history (animal exposure and bites)
59
Q

What is the primary treatment for infection by Pasteurella multicoda?

A
  • Penicillin (β-lactam - binds PBPs to inhibit cell wall synthesis)
    • Doxycycline (tetracycline - inhibits 30S ribosomal subunit) if patient has penicillin allergy
  • Cefuroxime (2nd gen. cephalo - binds PBPs to inhibit cell wall)

OR

  • Amoxicillin-Clavulanic acid (β-lactam + β-lactamase inhibitor)
  • Surgical drainage of wound
60
Q

___________________ is a Gram-positive, aerobic bacillus with simple growth requirements. It is catalase negative and primarily associated with swine and the external slime of fish.

A

Erysipelothrix rhusiopathiae

61
Q

Erysipelothrix rhusiopathiae is catalase (positive/negative).

A

Catalase negative

62
Q

Erysipelothrix rhusiopathiae is a (bacillus/coccus/coccobacillus/spirillum).

A

Bacillus

63
Q

Erysipelothrix rhusiopathiae is Gram-(positive/negative).

A

Positive (G+)

64
Q

Erysipelothrix rhusiopathiae is transmitted by __________________.

A

Direct cutaneous contact

  • Associated with swine and the external slime of fish
65
Q

What are the common occupations exposed to Erysipelothrix rhusiopathiae?

A
  • Fishing industry
  • Hog slaughtering
  • Meat processing/butchers
  • Veterinarians
  • Cooks
66
Q

___________ is a condition that is characterized by local skin cellulitis, pain, and symptom appearance within 2-7 days after exposure. It causes diffuse skin eruption and may lead to endocarditis if allowed to reach the blood stream. Bacterial ID is achieved by isolation of organisms from blood or tissue biopsy.

A

Erysipeloid

  • Caused by Erysipelothrix rhusiopathiae
67
Q

What is the primary treatment for erysipeloid caused by Erysipelothrix rhusiopathiae?

A
  • Penicillin (β-lactam - binds PBPs to inhibit cell wall synthesis)

MSK Test 1 (11 decks)

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