Human Diseases Caused by Bacteria Flashcards

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1
Q

Airborne Bacterial Pathogens

T/F: Of the bacterial species, most are pathogenic to humans.

A

FALSE – only few are pathogenic to humans

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2
Q

Airborne Bacterial Pathogens

What system do most bacterial diseases involve?

A

respiratory system
- some can disseminate into the bloodstream, particularly in elderly and immunocompromised

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3
Q

Diptheria-Exotoxin Mechanism

What is it caused by?

A

caused by Corynebacterium bacteria

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4
Q

Diptheria-Exotoxin Mechanism

Describe diptheria-exotoxins mechanism.

A
  • gram-positive
  • very resistant to drying
  • lysogenized strains produce an exotoxin that inhibits protein synthesis and is responsible for pathogenesis
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5
Q

Diptheria-Exotoxin Mechanism

How is it transmitted?

A

airborne transmission by nasopharyngeal secretions

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6
Q

Diptheria-Exotoxin Mechanism

What increases likelihood of transmission?

A

crowding

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7
Q

Diptheria

Who is diptheria typically seen in?

A

usually observed in individuals >30 years old with weakend immunity to diptheria toxin and living in tropical areas

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8
Q

Diptheria

How is diptheria diagnoses?

A
  • pseudomembrane in throat
  • bacterial culture
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9
Q

Diptheria

How is diptheria treated, prevented, and controlled?

A
  • antibiotic therapy
  • toxoid vaccine
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10
Q

Mycobacterium Infection

Where does these microorganisms live?

A

in soil, water, and house dust

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11
Q

Mycobacterium Infection

Mycobacterium causes a number of human infections that are hard to treat. Why is this true?

A
  • mycolic acid in cell wall is protective waxy material that is acid fast
  • resistant to penetration of some antibiotics
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12
Q

Mycobacterium Infection

MAC

A

M. avium complex

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13
Q

Mycobacterium Infection

Describe MAC.

A
  • normal inhabitatns of soil and water
  • infect variety of insects, birds, and other animals
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14
Q

Mycobacterium Infection

What are common allowances of mycobacterial infection in the US?

A

respiratory and gastrointestinal tracts have been proposed as portals of entry

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15
Q

Tuberculosis (TB)

What causes TB?

A

mycobacterium tuberculosis (Mtb), M. bovis, M africanum

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16
Q

Tuberculosis (TB)

Why is Tb considered a global health problem?

A

about 1/3 of world’s population is infected

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17
Q

Tuberculosis (TB)

What are some of the commonly infected groups?

A
  • US homeless
  • elderly
  • malnourished
  • alcoholic males
  • minorities
  • immigrants
  • prison populations
  • native americans
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18
Q

Tuberculosis (TB)

Does bacteria produce typical virulence factors?

A

no

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19
Q

Tuberculosis (TB)

What survival tactics do bacteria use?

A

unique lipids in the cell envelope are toxic to eukaryotic cells and create a barrier that protects the bacteria

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20
Q

Tuberculosis (TB)

How is it transmitted?

A
  • majority is person to person spread of droplet nuclei in respiratory tract
  • also transmitted from infected animals and their products
  • reactivation of old, dormant infection
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21
Q

Tuberculosis (TB)

What is the rate of progression?

A

disease develops slowly

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22
Q

TB Course of Disease

Lung macrophages that have phagocytosed Mtb often die in the attempt to kill bacteria. What is the result of this?

A

tubercles formation

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23
Q

TB Course of Disease

What are tubercles?

A

composed of bacteria, macrophages, T cells, and human proteins

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24
Q

TB Course of Disease

What are changes over time in tubercles?

A
  • caseous lesion
  • Ghon complexes
  • tuberculous cavities
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25
Q

TB Course of Disease

describe the appearance of caseous lesions.

A

cheese-like

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26
Q

TB Course of Disease

Ghon complexes

A

calcified caseous lesion

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27
Q

TB Course of Disease

tuberculous cavities

A
  • tubercle liquefies, forms air-filled cavity from which bacteria can spread
  • spreading is called miliary tb; also called reactivation tb because bacteria reactivated at intial infection site
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28
Q

Infection with Mtb

What is the basis tuberculin skin test?

A

development of cell-mediated immunity (sensitized T cells)

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29
Q

Infection with Mtb

How long is the incubation period?

A

4 to 12 weeks

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30
Q

Infection with Mtb

What are the symptoms?

A
  • fever, fatigue, night sweats, and weight loss
  • cough: characteristic of pulmonary involvement; may result in epectoration of bloody sputum
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31
Q

Infection with Mtb

How is it diagnosed?

A
  • observation of acid-fast bacteria
  • chest X-ray, Mantoux, or tuberculin skin test
  • DNA-based tests
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32
Q

Streptococcal Diseases

What is it caused by?

A

strep, group of gram-positive bacteria

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33
Q

Streptococcal Diseases

sterptococcus pyogenes

A

one of the most important pathogens;
- group A streptoccoci (GAS)
- beta-hemolytic streptococci

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34
Q

Streptococcal Diseases

What are the virulence factors?

A
  • extracellular enzymes that break down host molecules
  • streptokinases: dissolve clots
  • streptolysin O and S: kill host leukocytes
  • capsules and M protein, which limit phagocytosis
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35
Q

Streptococcal Pharyngitis

What is the common name of this infection?

A

strep throat

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36
Q

Streptococcal Pharyngitis

How is it transmitted?

A

droplets of saliva or nasal secretions

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37
Q

Streptococcal Pharyngitis

What is this the infection of?

A

throat: pharyngitis
tonsils: tonsilitis

38
Q

Streptococcal Pharyngitis

What are the physical manifestations?

A
  • redness
  • edema
  • lymph node enlargement in the throat
39
Q

Streptococcal Pharyngitis

T/F: Streptococcal pharyngitis can be diagnosed by the presence of symptoms.

A

FALSE – symptoms of disease not diagostic because many viral infections have similar presentation

40
Q

Streptococcal Pharyngitis

How is strep throat treated and controlled?

A

antibiotics important for children to lessen chance of complications (rheumatic fever and glomerulonephritis)

41
Q

Poststreptococcal Diseases

When do these occur?

A

1 to 4 weeks after an acute streptococcal infection

42
Q

Poststreptococcal Diseases

What is glomerulonephritis (Bright’s disease)?

A

inflammatory disease of the kidney

43
Q

Poststreptococcal Diseases

What is a possible result of chronic Bright’s disease?

A

may require a kidney transplant or lifelong renal dialysis

44
Q

Poststreptococcal Diseases

What is rheumatic fever?

A

an autoimmune disease affecting the heart valves, joints, subcutaneous tissues, and central nervous system

45
Q

Poststreptococcal Diseases

What is the most common cause of permanent heart valve damage in children?

A

rheumatic fever

46
Q

Arthropod-Borne Diseases

T/F: Bacteria cause a similar amount of arthropod-borne diseases as viruses and protozoa.

A

FALSE – bacteria cause fewer arthropod-borne diseases than do viruses and protozoa

47
Q

Arthropod-Borne Diseases

Which arthropod-borne diseases are of historical interest?

A

plague and typhus

48
Q

Arthropod-Borne Diseases

What are some newly emerged arthropod-borne diseases?

A

lyme disease and ehrlichiosis

49
Q

Arthropod-Borne Diseases

What is the most common tick-borne disease in the US?

A

lyme disease

50
Q

Arthropod-Borne Diseases

What is Lyme Disease caused by?

A
  • borrelia burgdorferi (most common in US)
  • B. garinii
  • B. afzelii (most common in Europe)
51
Q
A
52
Q

Arthropod-Borne Diseases

How is lyme disease transmitted?

A

transmitted from animal reservoirs by ticks

53
Q

Arthropod-Borne Diseases

What are examples of animal reservoirs for lyme disease?

A
  • deer
  • field mice
  • woodrats
54
Q

Arthropod-Borne Diseases

What are the general stages of Lyme Disease?

A
  • localized stage
  • disseminated stage
  • late stage
55
Q

Arthropod-Borne Diseases

Lyme Disease: localized stage

A
  • develops after 7 to 10 days
  • expanding, ring-shaped, skin lesion
  • flulike symptoms
56
Q

Arthropod-Borne Diseases

Lyme Disease: Disseminated stage

A
  • occurs weeks or months after infection
  • neurological abnormalities, heart inflammation, and arthritis (lyme arthritis may be an autoimmune response to joint MHC which are similar to bacterial antigens)
57
Q

Arthropod-Borne Diseases

Lyme Disease: Late stage

A
  • occurs years later
  • demyelination of neurons, behavioral changes, and symptoms resembling Alzheimer’s disease and multiple sclerosis
58
Q

Arthropod-Borne Diseases

What is the plague caused by?

A

yersinia pestis (gram-negative)

59
Q

Arthropod-Borne Diseases

How is the plague transmitted?

A

rodent to human
- bite of infected flea, direct contact with infected animal or products

60
Q

Arthropod-Borne Diseases

How is pneumonic plague transmitted?

A

inhalation of contaminated airborne droplets

61
Q

Arthropod-Borne Diseases

What does the plague do within the body?

A

multiply in blood and lymph
- survive and proliferate in phagocytic cells
- enlarged lymph nodes (buboes)

62
Q

Arthropod-Borne Diseases

What are the virulence factors of the plague?

A
  • proliferates in phagocytes, not killed
  • type III secretion systems deliver yersinial outer membrane proteins (YOPS) into cells whcih shut down defense mechanisms
63
Q

Direct Contact Diseases

What do most direct contact diseases involve?

A
  • skin
  • underlying tissues
  • mucous membranes
  • some can become disseminated
64
Q

Direct Contact Diseases

What are examples of direct contact diseases?

A
  • gas gangrene
  • Group B streptococcus (GBS)
  • leprosy
  • peptic ulcers
  • chlamydia
  • gonorrhea
  • syphilis staph infections
65
Q

Sexually Transmitted Infections

STIs are a major worldwide public health problem. How many new cases occur every day?

A

1 million

66
Q

Sexually Transmitted Infections

Some STIs can be transmitted by ??.

A

nonsexual means

67
Q

Sexually Transmitted Infections

T/F: All STIs are cured easily.

A

FALSE – some are cured easily, other are difficult or impossible to cure

68
Q

Sexually Transmitted Infections

What age group has the highest frequency of STIs?

A

15- to 3- year age group but also others sexually active

69
Q

Sexually Transmitted Infections

What is the most frequently reported sexually transmitted bacterial disease?

A

Chlamydia

70
Q

Sexually Transmitted Infections

What is the most commonly isolated species of chlamydia?

A

chlamydia trachomatis

71
Q

Sexually Transmitted Infections

How is chlamydia transmitted?

A

anal, oral and vaginal sex
- can also be transmitted from mother to child during vaginal childbirth

72
Q

Sexually Transmitted Infections

The Intracellular Lifecycle of Chlamydia

A
  • biphasic developmental cycle
    elementary body (EB)
    reticulate body (RB)
  • deviates from endolysosomal pathway
    traffics along microtubules organizing center
    engages
  • engages host proteins involved in membrane trafficking
  • translocates bacterial virulence proteins (effectors) at all stages
73
Q

Sexually Transmitted Infections

C. trachomatis translocates over 100 proteins via ??.

A

a type III secretion system (T3SS)
- thats over 12% of total proteome

74
Q

Sexually Transmitted Infections

Chlamydia: The inclusion membrane is modified by the insertion of T3SS proteins, which are called?

A

inclusion membrane proteins (Incs)

75
Q

Sexually Transmitted Infections

What are Incs characterized by?

A

long hydrophobic domain

76
Q

Sexually Transmitted Infections

What are the clinical manifestations of Chlamydia in males?

A
  • asymptomatic
    OR
  • urethral discharge
  • burning during urination
  • itching
77
Q

Sexually Transmitted Infections

What are the clinical manifestations of Chlamydia in females?

A
  • asymptomatic
    OR
  • may have severe infection of cervix and urethra
  • may cause PID
  • if pregnant, can lead to miscarriage, stillbirth, inclusion conjuctivitis, and infant pneumonia
78
Q

Sexually Transmitted Infections

How is chlamydia treated?

A

antibiotics

79
Q

Trachoma

What is trachoma?

A

the greatest single cause of blindness throughout the world

80
Q

Trachoma

What causes Trachoma?

A

caused by C. trachomatis serotypes A-C

81
Q

Trachoma

How is trachoma transmitted?

A
  • contact with infected soaps and towels
  • flies
82
Q

Trachoma

How is trachoma treated, prevented, and controlled?

A
  • Diagnosis and treatment: same as for inclusion conjunctivitis
  • health education
  • personal hygiene
  • access to clean water for washing
83
Q

Trachoma

What are the symptoms of a first time infection of trachoma?

A
  • abrupt onset of inflamed conjunctiva, leading to inflammatory cell exudate and necrotic eyelash follicles
  • usually heals spontaneously
84
Q

Trachoma

What are the symptoms of a reinfection of trachoma?

A
  • pannus formation (vascularization of cornea), leading to scarring of the conjunctiva
  • if scarring of cornrea also occurs, blindness results
85
Q

Staphylococcal Diseases - Causative Agents

Describe members of the genus staphylococcus.

A
  • gram-positive, pyogenic cocci
  • normal inhabitants of upper respiratory tract, skin, intestines, and vagina
86
Q

Staphylococcal Diseases - Causative Agents

S. aureus

A

coagulase-positive, pathogenic

87
Q

Staphylococcal Diseases - Causative Agents

Many pathogenic strains are slime producers. What are the benefits of this?

A
  • allows them to adhere to smooth surfaces such as prosthetic medical devices and catheters
  • inhibits neutrophil chemotaxis, phagocytosis, and antimicrobial agents
88
Q

Staphylococcal Diseases

What are Staphylococcal Diseases harbored by?

A

asymptomatic carriers or active carriers

89
Q

Staphylococcal Diseases

How are Staphylococcal Diseases transmitted?

A
  • spread by hands, inanimate objects or expelled by respiratory tract
  • through blood
90
Q

Staphylococcal Diseases

T/F: Staphylococcal Diseases may produce disease in almost every organ and tissue.

A

TRUE – immunocompromised individuals are at most risk

91
Q
A