Human Diseases Caused by Bacteria Flashcards
(91 cards)
1
Q
Airborne Bacterial Pathogens
T/F: Of the bacterial species, most are pathogenic to humans.
A
FALSE – only few are pathogenic to humans
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
3
Q
Diptheria-Exotoxin Mechanism
What is it caused by?
A
caused by Corynebacterium bacteria
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
5
Q
Diptheria-Exotoxin Mechanism
How is it transmitted?
A
airborne transmission by nasopharyngeal secretions
6
Q
Diptheria-Exotoxin Mechanism
What increases likelihood of transmission?
A
crowding
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
8
Q
Diptheria
How is diptheria diagnoses?
A
- pseudomembrane in throat
- bacterial culture
9
Q
Diptheria
How is diptheria treated, prevented, and controlled?
A
- antibiotic therapy
- toxoid vaccine
10
Q
Mycobacterium Infection
Where does these microorganisms live?
A
in soil, water, and house dust
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
12
Q
Mycobacterium Infection
MAC
A
M. avium complex
13
Q
Mycobacterium Infection
Describe MAC.
A
- normal inhabitatns of soil and water
- infect variety of insects, birds, and other animals
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
15
Q
Tuberculosis (TB)
What causes TB?
A
mycobacterium tuberculosis (Mtb), M. bovis, M africanum
16
Q
Tuberculosis (TB)
Why is Tb considered a global health problem?
A
about 1/3 of world’s population is infected
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
18
Q
Tuberculosis (TB)
Does bacteria produce typical virulence factors?
A
no
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
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
21
Q
Tuberculosis (TB)
What is the rate of progression?
A
disease develops slowly
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
23
Q
TB Course of Disease
What are tubercles?
A
composed of bacteria, macrophages, T cells, and human proteins
24
Q
TB Course of Disease
What are changes over time in tubercles?
A
- caseous lesion
- Ghon complexes
- tuberculous cavities
25
# TB Course of Disease
describe the appearance of caseous lesions.
cheese-like
26
# TB Course of Disease
Ghon complexes
calcified caseous lesion
27
# TB Course of Disease
tuberculous cavities
- 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
28
# Infection with Mtb
What is the basis tuberculin skin test?
development of cell-mediated immunity (sensitized T cells)
29
# Infection with Mtb
How long is the incubation period?
4 to 12 weeks
30
# Infection with Mtb
What are the symptoms?
- fever, fatigue, night sweats, and weight loss
- cough: characteristic of pulmonary involvement; may result in epectoration of bloody sputum
31
# Infection with Mtb
How is it diagnosed?
- observation of acid-fast bacteria
- chest X-ray, Mantoux, or tuberculin skin test
- DNA-based tests
32
# Streptococcal Diseases
What is it caused by?
strep, group of gram-positive bacteria
33
# Streptococcal Diseases
sterptococcus pyogenes
one of the most important pathogens;
- group A streptoccoci (GAS)
- beta-hemolytic streptococci
34
# Streptococcal Diseases
What are the virulence factors?
- extracellular enzymes that break down host molecules
- streptokinases: dissolve clots
- streptolysin O and S: kill host leukocytes
- capsules and M protein, which limit phagocytosis
35
# Streptococcal Pharyngitis
What is the common name of this infection?
strep throat
36
# Streptococcal Pharyngitis
How is it transmitted?
droplets of saliva or nasal secretions
37
# Streptococcal Pharyngitis
What is this the infection of?
throat: pharyngitis
tonsils: tonsilitis
38
# Streptococcal Pharyngitis
What are the physical manifestations?
- redness
- edema
- lymph node enlargement in the throat
39
# Streptococcal Pharyngitis
T/F: Streptococcal pharyngitis can be diagnosed by the presence of symptoms.
FALSE -- symptoms of disease not diagostic because many viral infections have similar presentation
40
# Streptococcal Pharyngitis
How is strep throat treated and controlled?
antibiotics important for children to lessen chance of complications (rheumatic fever and glomerulonephritis)
41
# Poststreptococcal Diseases
When do these occur?
1 to 4 weeks after an acute streptococcal infection
42
# Poststreptococcal Diseases
What is glomerulonephritis (Bright's disease)?
inflammatory disease of the kidney
43
# Poststreptococcal Diseases
What is a possible result of chronic Bright's disease?
may require a kidney transplant or lifelong renal dialysis
44
# Poststreptococcal Diseases
What is rheumatic fever?
an autoimmune disease affecting the heart valves, joints, subcutaneous tissues, and central nervous system
45
# Poststreptococcal Diseases
What is the most common cause of permanent heart valve damage in children?
rheumatic fever
46
# Arthropod-Borne Diseases
T/F: Bacteria cause a similar amount of arthropod-borne diseases as viruses and protozoa.
FALSE -- bacteria cause fewer arthropod-borne diseases than do viruses and protozoa
47
# Arthropod-Borne Diseases
Which arthropod-borne diseases are of historical interest?
plague and typhus
48
# Arthropod-Borne Diseases
What are some newly emerged arthropod-borne diseases?
lyme disease and ehrlichiosis
49
# Arthropod-Borne Diseases
What is the most common tick-borne disease in the US?
lyme disease
50
# Arthropod-Borne Diseases
What is Lyme Disease caused by?
- borrelia burgdorferi (most common in US)
- B. garinii
- B. afzelii (most common in Europe)
51
52
# Arthropod-Borne Diseases
How is lyme disease transmitted?
transmitted from animal reservoirs by ticks
53
# Arthropod-Borne Diseases
What are examples of animal reservoirs for lyme disease?
- deer
- field mice
- woodrats
54
# Arthropod-Borne Diseases
What are the general stages of Lyme Disease?
- localized stage
- disseminated stage
- late stage
55
# Arthropod-Borne Diseases
Lyme Disease: localized stage
- develops after 7 to 10 days
- expanding, ring-shaped, skin lesion
- flulike symptoms
56
# Arthropod-Borne Diseases
Lyme Disease: Disseminated stage
- 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
# Arthropod-Borne Diseases
Lyme Disease: Late stage
- occurs years later
- demyelination of neurons, behavioral changes, and symptoms resembling Alzheimer's disease and multiple sclerosis
58
# Arthropod-Borne Diseases
What is the plague caused by?
yersinia pestis (gram-negative)
59
# Arthropod-Borne Diseases
How is the plague transmitted?
rodent to human
- bite of infected flea, direct contact with infected animal or products
60
# Arthropod-Borne Diseases
How is pneumonic plague transmitted?
inhalation of contaminated airborne droplets
61
# Arthropod-Borne Diseases
What does the plague do within the body?
multiply in blood and lymph
- survive and proliferate in phagocytic cells
- enlarged lymph nodes (buboes)
62
# Arthropod-Borne Diseases
What are the virulence factors of the plague?
- proliferates in phagocytes, not killed
- type III secretion systems deliver yersinial outer membrane proteins (YOPS) into cells whcih shut down defense mechanisms
63
# Direct Contact Diseases
What do most direct contact diseases involve?
- skin
- underlying tissues
- mucous membranes
- some can become disseminated
64
# Direct Contact Diseases
What are examples of direct contact diseases?
- gas gangrene
- Group B streptococcus (GBS)
- leprosy
- peptic ulcers
- chlamydia
- gonorrhea
- syphilis staph infections
65
# Sexually Transmitted Infections
STIs are a major worldwide public health problem. How many new cases occur every day?
1 million
66
# Sexually Transmitted Infections
Some STIs can be transmitted by ??.
nonsexual means
67
# Sexually Transmitted Infections
T/F: All STIs are cured easily.
FALSE -- some are cured easily, other are difficult or impossible to cure
68
# Sexually Transmitted Infections
What age group has the highest frequency of STIs?
15- to 3- year age group but also others sexually active
69
# Sexually Transmitted Infections
What is the most frequently reported sexually transmitted bacterial disease?
Chlamydia
70
# Sexually Transmitted Infections
What is the most commonly isolated species of chlamydia?
chlamydia trachomatis
71
# Sexually Transmitted Infections
How is chlamydia transmitted?
anal, oral and vaginal sex
- can also be transmitted from mother to child during vaginal childbirth
72
# Sexually Transmitted Infections
The Intracellular Lifecycle of Chlamydia
- 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
# Sexually Transmitted Infections
C. trachomatis translocates over 100 proteins via ??.
a type III secretion system (T3SS)
- thats over 12% of total proteome
74
# Sexually Transmitted Infections
Chlamydia: The inclusion membrane is modified by the insertion of T3SS proteins, which are called?
inclusion membrane proteins (Incs)
75
# Sexually Transmitted Infections
What are Incs characterized by?
long hydrophobic domain
76
# Sexually Transmitted Infections
What are the clinical manifestations of Chlamydia in males?
- asymptomatic
**OR**
- urethral discharge
- burning during urination
- itching
77
# Sexually Transmitted Infections
What are the clinical manifestations of Chlamydia in females?
- 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
# Sexually Transmitted Infections
How is chlamydia treated?
antibiotics
79
# Trachoma
What is trachoma?
the greatest single cause of blindness throughout the world
80
# Trachoma
What causes Trachoma?
caused by C. trachomatis serotypes A-C
81
# Trachoma
How is trachoma transmitted?
- contact with infected soaps and towels
- flies
82
# Trachoma
How is trachoma treated, prevented, and controlled?
- Diagnosis and treatment: same as for inclusion conjunctivitis
- health education
- personal hygiene
- access to clean water for washing
83
# Trachoma
What are the symptoms of a first time infection of trachoma?
- abrupt onset of inflamed conjunctiva, leading to inflammatory cell exudate and necrotic eyelash follicles
- usually heals spontaneously
84
# Trachoma
What are the symptoms of a reinfection of trachoma?
- pannus formation (vascularization of cornea), leading to scarring of the conjunctiva
- if scarring of cornrea also occurs, blindness results
85
# Staphylococcal Diseases - Causative Agents
Describe members of the genus staphylococcus.
- gram-positive, pyogenic cocci
- normal inhabitants of upper respiratory tract, skin, intestines, and vagina
86
# Staphylococcal Diseases - Causative Agents
S. aureus
coagulase-positive, pathogenic
87
# Staphylococcal Diseases - Causative Agents
Many pathogenic strains are slime producers. What are the benefits of this?
- allows them to adhere to smooth surfaces such as prosthetic medical devices and catheters
- inhibits neutrophil chemotaxis, phagocytosis, and antimicrobial agents
88
# Staphylococcal Diseases
What are Staphylococcal Diseases harbored by?
asymptomatic carriers or active carriers
89
# Staphylococcal Diseases
How are Staphylococcal Diseases transmitted?
- spread by hands, inanimate objects or expelled by respiratory tract
- through blood
90
# Staphylococcal Diseases
T/F: Staphylococcal Diseases may produce disease in almost every organ and tissue.
TRUE -- immunocompromised individuals are at most risk
91
