Microbiology > Lesson 2.5 & 2.6 - Pathogenicity & Antimicrobials > Flashcards

Lesson 2.5 & 2.6 - Pathogenicity & Antimicrobials Flashcards

(54 cards)

Study These Flashcards
1
Q

Define pathogenicity

A

Ability of an organism to cause damage / disease to a host that it infects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define virulence

A

Degree of pathogenicity; a phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define avirulence

A

Not a pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define disease

A

Disruption of homeostasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Pathogens express genes that code for ____________

A

virulence factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Virulent pathogens have a ____ threshold than less virulent relatives

A

less; that means it takes fewer to cause disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Some pathogens employ a _____ growth strategy to avoid immune system

A

slow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Treponema pallidum incites…

A

Syphillis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

LD50

A

lethal dose of LETHAL pathogens; expressed as # of organisms required to kill 50% of test animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which is more virulent: Streptococcus pyogenes OR Salmonella enterica serovar Typhimurium

A

Streptococcus pyogenes (according to LD50)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

ID50

A

infectious dose of NONLETHAL pathogens; expressed as # of organisms to cause illness in 50% of test animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Opportunistic pathogens

A

Avirulent organisms that cause disease when host’s immune system is weakened; severe burns may result in this

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What causes oral thrush / candidiasis in HIV patients?

A

Candida albicans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What causes lung infections of cystic fibrosis patients?

A

Psuedomonas aeruginosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Virulence Continuum

A

Lactobacilli, Candida albicans, Clostridium difficile, Pseudomonas aeruginosa, Bordetella pertussis, Yersinia pestis, Francisella tularensis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Types of virulence factors

A

Adhesions, extracellular enzymes, exotoxins, endotoxins, antiphagocytic factors, biofilm formation, phase variation / antigenic shift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Adhesion factors

A

Specialized attachment proteins on fimbriae, flagella & capsule;
Viruses & bacteria have lipoproteins & glycoproteins that bing to host receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Neisseria gonorrhoeae

A
  • STI - gonorrhea
  • Fimbriae adhesion proteins
  • Binds to genitourinary system lining cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Extracellular enzymes

A

Released by BACTERIA to degrade host molecules and evade immune system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Hemolysins

A

cause lysis of RBCs; extracellular enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Hyauronidase

A

Degrades hyaluronic acid; extracellular enzyme
Connective, epithelial, and neural tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Collagenase

Study These Flashcards
A

Degrades collagen; extracellular enzyme

23
Q

Coagulase

Study These Flashcards
A

Promotes blood clots; extracellular enzyme

24
Q

Kinase

Study These Flashcards
A

digest blood clots; extracellular enzyme

25
*Necrotizing fasciitis*
Deeper skin & connective tissue; **c****ysteine protease**
26
Toxins
* interfere with biochemical, cellular, enzymatic, and metabolic process * enter bloodstream & carried to other parts of body * some enzymes act as toxins, some toxins have enzymatic activity
27
Exotoxins
* proteins (most are enzymes), soluble, diffusible, high toxicity * inhibit metabolic function * produced by **Gram (-) AND Gram (+)** bacteria * often exotoxin causes symptoms, not bacterium
28
Cytotoxins
kill host cells or inhibit function; type of **exotoxin**
29
Neurotoxins
interfere with normal nerve impulse transmission; type of **exotoxin**
30
Enterotoxins
affect epithelial cells of GI tract; type of **exotoxin**
31
Antitoxins
antibodies that neutralize toxin
32
Toxoids (& example)
Inactivated toxins used as vaccines e.g. Tdap (Diptheria, Tetanus, Botulism)
33
*E. coli* O157:H7
* Can lead to post-diarrheal hemolytic uremic syndrome (HUS) * Produces cytotoxin (protein synthesis); Shiga-toxin * Inflammatory response
34
Post diarrheal hemolytic uremic syndrome (HUS) characteristics
* **Thrombocytopenia** * Decrease in platelet # * **Microangiopathic hemolytic anemia** * Misshapen/fragmented cells may clog kidney capillaries * **Acute renal injury**
35
A B Toxins
* Subunit A = enzymatic acticity, catalyzes cAMP from ATP * Subunit B = binds & transfers
36
cAMP function
* cyclic AMP; signals cells to dischard gluids into intestinal lumen * Severe watery diarrhea
37
*Vibrio cholerae*
cholera toxin, enterotoxin
38
Botulinum Toxin
* Neurotoxin by ***Clostridium botulinum*** (when spores germinate) * Binds to motor neurons & prevents acetylcholine release * Paralysis & suffocation (diaphragm) * **10 ng** = lethal
39
Tetanus Toxin
* Neurotoxin by ***Clostridium tetani*** * Binds to motor neurons * Uncontrollable muscle contractions - can break bones * **50 ng** = lethal
40
Endotoxins
* **Gram (-) cells die, release lipid A** * **​**Causes macrophages to release **cytokines** * **​**Travel throughout host * Low toxicity; fatal in high concentrations
41
Increased cytokines lead to...
Blood vessel dilation & leakage, fever, coagulation, hemorrhaging, inflammation, shock
42
Antiphagocytic factors
Characteristics that inhibit phagocytosis
43
Capsule
Protects bacterial cell & evades host immune system
44
($) Examples of killing/injuring phagocytes
* ***Pseudomonas aeruginosa* exotoxin A** kills macrophages * **Pathogenic staphylococci** produce leukocidin * **Pathogenic streptococci** produce streptolysin * **Pyogenic cocci** (Gram +, produce pus) produce hemolysins
45
(5) Mechanisms of Avoiding or Confusing Phagocytes
* Some don't illicit overwhelming immune response * Release compounds that inhibit phagocyte chemotaxis (send pathogens wrong direction) * Camouflage * Cover surface w/ host cell proteins * Prevent phagolysosome formation
46
Phagolysosome (& [3] resistance mechanisms)
* Phagocyte with lysosome (degradative enzyme) * Some bacteria inhibit lysosome/phagosome fusion * Some inactivate enzymes * Some escape
47
*Legionella pneumophilia*
Example of bacteria surviving in phagolysosome
48
Biofilms characteristics
* Microbial community (mono or poly - physiologically integrated) * Extracellular polysaccharide * Prevents antibiotics penetration * Promotes HGT * Associated with chronic infections
49
Quorum Sensing
mechanism by bacteria to **monitor population density & regulate behavior**
50
Behavior of quorum sensing (4)
* Biofilm recruitment * conjugation * pathogenesis * production of extracellular polysaccharides
51
Types of autoinducers (3)
* N-acylhomoserine lactones (AHLs) * Autoinducing peptides * Autoinducer-2
52
Antigenic Variation & Types
* Bacterial pathogens may change surface to avoid host immune response * Fimbriae, outer membrane proteins, capsule, flagella
53
Antigenic Drift
Viral mutation during replication
54
Antigenic Shift
Reassortment; both viral types incorporated
Microbiology
flashcards
Decks in class (17)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions