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MICRB 106 - FINAL > Rickettsias, Chlamydias, Spirochetes, and Vibrios > Flashcards

Rickettsias, Chlamydias, Spirochetes, and Vibrios Flashcards

1
Q

What is the most common genus of rickettsias associated with human diseases?

A

Rickettsiae

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2
Q

Rickettsias got their name from ______

A

Howard Ricketts

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3
Q

Where do rickettsias live inside their host’s cells?

A

The cytosol

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4
Q

Why are rickettsias obligate intracellular parasites?

A

They cannot use glucose and must find nutrients in the cytosol

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5
Q

What is the fate of a rickettsia outside of its host’s cells?

A

Becomes unstable and dies

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6
Q

Transmission of rickettsias from host to host requires a ______

A

Vector

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7
Q

What is the causative agent of Rocky Mountain spotted fever (RMSF)?

A

R. rickettsii

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8
Q

What kind of arthropod introduces the causative agent of RMSF to human hosts?

A

Hard ticks

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9
Q

Why does it take several hours of feeding by the vector for R. rickettsii bacteria to become infective?

A

They are dormant in the salivary glands of tick vectors

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10
Q

Describe how R. rickettsia enters the cytosol of blood vessel endothelial cells (2)

A
  • Triggers endocytosis
  • Lyses the endosome’s membrane
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11
Q

______ cause leakage of blood into tissues in RMSF

A

Damaged endothelial cells

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12
Q

What are the immediate physiological consequences due to leakage of blood into tissues? (2)

A
  • Hypotension
  • Insufficient nutrients / oxygen
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13
Q

Describe the rash associated with RMSF

A

Spotted non-itchy rash

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14
Q

How is RMSF treated? (2)

A
  • Removal of tick
  • Antibiotics
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15
Q

How is RMSF prevented? (3)

A
  • Tight-fitting clothing
  • Tick repellent
  • Avoiding tick-infected areas
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16
Q

Obligate intracellular chlamydias are restricted to the ______ of host cells

A

Vesicles

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17
Q

What is the morphology of chlamydial elemental bodies (EBs)?

A

Tiny cocci

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18
Q

What is the morphology of chlamydial reticulate bodies (RBs)?

A

Large pleomorphic

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19
Q

Describe chlamydial elemental bodies (EBs) (3)

A
  • Dormant
  • Infective
  • Extracellular
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20
Q

Describe chlamydial reticulate bodies (RBs) (2)

A
  • Non-infective
  • Intracellular
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21
Q

Chlamydial reticulate bodies (RBs) replicate within ______

A

Phagosomes

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22
Q

Why are chlamydias called ‘energy parasites’?

A

They lack enzymes needed to synthesize ATP

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23
Q

Describe EBs / RBs in the life cycle of chlamydias (3)

A
  • EBs trigger endocytosis
  • EBs convert into RBs
  • EBs are released via exocytosis
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24
Q

Inclusion bodies occur in the life cycle of chlamydias when the infected vesicle becomes filled with ______

A

RBs

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25
Q

What is the host range for Chlamydia trachomatis?

A

Humans

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26
Q

How does Chlamydia trachomatis enter the human body?

A

Abrasions / lacerations

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27
Q

What are the 2 major body systems by which Chlamydia trachomatis enters a human body?

A
  • Conjunctiva
  • Mucous membranes
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28
Q

What is the causative agent of lymphogranuloma venereum?

A

C. trachomatis

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29
Q

Why is the initial lesion of lymphogranuloma venereum often overlooked?

A

It is painless and heals rapidly

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30
Q

The second stage of lymphogranuloma venereum is characterized by development of ______

A

Buboes

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31
Q

How do urethritis / proctitis develop from LGV strains of C. trachomatis?

A

Lymphatic spread

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32
Q

What is proctitis?

A

Inflammation of the rectum

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33
Q

What is the causative agent of trachoma?

A

C. trachomatis

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34
Q

What is trachoma?

A

Non-traumatic blindness

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35
Q

Describe the pathology that causes blindness from trachoma (3)

A
  • Multiplies in the conjunctiva
  • Eyelids turn inward
  • Cornea fills with blood
36
Q

What does the term spirochete mean in Greek?

A

Coiled hairs

37
Q

What is the morphology of a spirochete?

A

Helical axial filaments

38
Q

Where are axial filaments and endoflagella located?

A

Between the cytoplasmic membrane and outer membrane

39
Q

Describe the mechanism by which spirochetes move through their environment (2)

A
  • Axial filament rotates
  • Spirochetes corkscrew through the environment
40
Q

What is the causative agent of syphilis?

A

T. pallidum

41
Q

What qualities make T. pallidum an obligate intracellular parasite? (2)

A
  • Fastidiousness
  • Environmental sensitivity
42
Q

What is the host range for T. pallidum?

A

Humans

43
Q

How is T. pallidum transmitted?

A

Sexual contact

44
Q

Chancre formation and millions of spirochetes refers to ______ syphilis

A

Primary

45
Q

Spreading through the bloodstream and a widespread rash refers to ______ syphilis

A

Secondary

46
Q

Disappearance of rash refers to ______ syphilis

A

Latent

47
Q

Gumma formation refers to ______ syphilis

A

Tertiary

48
Q

Tertiary syphilis is NOT associated with effects of ______

A

Treponema

49
Q

Latent syphilis can last ______ years

A

30 or more

50
Q

What is a chancre?

A

Small, painless red lesion

51
Q

Why are chancres considered to be extremely contagious?

A

They are filled with spirochetes

52
Q

What tissues or organs are affected by tertiary syphilis?

A

ANY

53
Q

What are gummas?

A

Rubbery, painful, swollen lesions

54
Q

What is the causative agent of Lyme disease?

A

B. burgdoferi

55
Q

From what incident did Lyme disease get its name?

A

The extremely high incidence of childhood rheumatoid arthritis in Lyme, Connecticut

56
Q

What kind of arthropod introduces the causative agent of Lyme disease to human hosts?

A

Hard ticks

57
Q

Erythma migrans refers to phase ______ of Lyme disease

A

1

58
Q

Neurological symptoms and cardiac dysfunction refers to phase ______ of Lyme disease

A

2

59
Q

Severe arthritis refers to phase ______ of Lyme disease

A

3

60
Q

What is erythma migrans?

A

A bull’s eye rash

61
Q

Why should people living in areas where Lyme disease is prevalent take precautions particularly during spring and early summer?

A

Nymphs are feeding during this time

62
Q

What kinds of repellents should be used to avoid contracting Lyme disease?

A

DEET repellents

63
Q

What is the morphology for the genus Vibrio?

A

Curved bacilli

64
Q

Where do Vibrio bacteria naturally live?

A

Marine environments

65
Q

What is the causative agent of cholera?

A

V. cholerae

66
Q

What is the specific reservoir for V. cholerae?

A

Freshwater

67
Q

______ played an important role in understanding the spread of cholera

A

John Snow

68
Q

How do humans become infected with V. cholerae?

A

Ingestion of contaminated food / water

69
Q

Describe the effects of serious cases of cholera in the body (2)

A
  • Fluid and electrolyte loss
  • Watery, colorless, odorless stool
70
Q

How is ‘rice-water stool’ associated with the above pathology?

A

Stool flecked with mucus

71
Q

What is cholera toxin?

A

Exotoxin / virulence factor of V. cholerae

72
Q

What is the specific role of the cholera toxin B subunits?

A

Bind receptors of intestinal epithelial cells

73
Q

What is the function of the A1 cholera toxin subunit after entering the cell’s cytosol?

A

Activates adenylate cyclase (AC)

74
Q

What is the function of activated adenylate cyclase regarding cholera?

A

Converts ATP into cAMP

75
Q

What specific effect does cAMP have upon intestinal epithelial cells?

A

Secretion of electrolytes

76
Q

What specific effect does electrolyte secretion have upon the intestinal lumen?

A

Water follows the movement of electrolytes into the intestinal lumen

77
Q

What causes dehydration, kidney failure, coma, or death associated with cholera?

A

Severe fluid and electrolyte loss

78
Q

What is the treatment for cholera?

A

Fluid and electrolyte replacement

79
Q

What is the morphology for H. pylori?

A

Helical and motile

80
Q

What organ in the body does H. pylori colonize?

A

The stomach

81
Q

What is the causative agent of microbial gastritis and most peptic ulcers?

A

H. pylori

82
Q

How does urease serve as a virulence factor for H. pylori? (3)

A
  • Degrades urea
  • Produces alkaline ammonia
  • Neutralizes stomach acid
83
Q

How does the formation of a peptic ulcer begin?

A

H. pylori borrows through the protective mucus of the stomach

84
Q

What is the effect of colonization / multiplication of H. pylori on the lining of the stomach?

A

Acids digest the stomach lining

85
Q

How does H. pylori gain access to underlying muscle tissue and blood vessels?

A

The epithelial layer becomes ulcerated

MICRB 106 - FINAL (4 decks)

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