Lecture 16: Infection&Pathogenicity Flashcards
(53 cards)
1
Q
What is the name of a molecule that can recognized as non-self by the immune system?
A
antigen
2
Q
What type of bacteria often have LPS on their surface?
A
Gram negative
3
Q
What are 3 chemical barriers pathogens must overcome?
A
Lysozyme (tears), lactoferrin (milk), bacteriocins (microbiota)
4
Q
How can bacteria pass genes between cells?
A
Horizontal gene transfer
5
Q
Host
A
larger organism that supports the survival and growth of the pathogenic organism
6
Q
Infection
A
- microbe grows on/in host
- May not result in overt symptoms or disease
7
Q
Infectious disease
A
- any change from state of health
- part of all the host is incapacitated due to pathogen or its products
8
Q
Pathogen
A
- any organism that causes disease
9
Q
Opportunistic pathogen
A
- part of the normal microbiota that only causes disease when host is immunocompromised
10
Q
Pathogenicity
A
- ability of a pathogen to cause disease
11
Q
Virulence
A
- degree of harm inflicted on the host
12
Q
Extracellular pathogens
A
- remain in tissues and fluids but never enter host cells during disease
13
Q
Intracellular pathogens
A
- grows and multiply within host cells
14
Q
Facultative intracellular pathogens
A
- reside within the cells of the host or in the environment
15
Q
Obligate intracellular pathogens
A
- ONLY grow inside the host cells
16
Q
Infectious disease course
A
- incubation period
- prodromal stage
- illness period
- convalescence
17
Q
Incubation period
A
- time between pathogen entry and development of signs and symptoms
18
Q
Prodromal stage
A
- Mild, non specific signs and symptoms
19
Q
illness period
A
- disease is most severe ad display signs and symptoms
20
Q
Convalescence
A
- recovery stage
21
Q
The host provides the pathogen:
A
- protection
- nutrients
- energy to use
22
Q
Reservoir
A
- source of pathogens
- natural environmental location in which the pathogen normally resides
23
Q
Vector
A
- organism that spreads disease from one host to another
- ex. mosquitos, ticks, fleas, mites, or biting flies
24
Q
Direct transmission
A
- droplets: saliva, mucus
- horizontal contact: kissing, sex
- vertical contact: mother to child, herpes
- vector: infection passed by another animal
25
Indirect transmission
1. Fomites: mediated by inanimate object
2. fecal/oral: contaminated food and water
3. Aerosols: particles that remain in air (Covid19)
26
Portal of entry
- skin, respiratory, gastrointestinal, urogenital system
- attachment of microbe to target cell is first
27
Colonization
- establish a site of microbial replication on or within host
28
Adherence mechanisms
- adhesions have high degree of specificity to target tissues
29
Adherence structures
1. pili
2. fimbriae
3. membrane and capsular materials
4. specialized adhesion molecules on microbe's cell surface
30
Bacteremia
- invasion
- presence of viable bacteria in the blood
31
Septicemia
- bacterial or fungal toxins in the blood
32
Surviving host defenses
- survive and replicate inside host cells
- squeeze between host cells
- produce type VI secretion system
- make capsules to avoid phagocytosis
33
suppression of host immune response
- infect cells of the immune system and diminish their function while ensuring their own survival
- eliminate O-antigen of lipopolysaccharide to diminish immune recognition and clearance
34
Mucoid capsule
- prevents phagocytosis by host immune cells
35
Phase variation
- changing gene expression to hide from host immune system
- results in new, unrecognized antigens on surface
36
Biofilm
- protected fro nutrient deprivation, predators, antimicrobial agents and host immune cells
37
Virulence factors
- large segemnts of bacterial chromosomal and plasmid DNA found to encode
38
Pathogenicity islands
- increase bacterial virulence
- absent in nonpathogenic members of sam genus or species
- genes can spread from one bacterial cell to another
39
Toxin
- substance that disrupts the normal metabolism of host cells
40
Toxigenicity
- pathogen's ability to produce toxins
41
Intoxications
- disease that result from entry of a specific pre-formed toxin into host
42
Damage to the host (Exotoxins)
- heat-labile proteins
- travel from site of infection to other body tissues or target cells
- encoded by genes on plasmids or prophages within bacteria
43
Superantigens
- stimulate abt 30% of host T cells of the immune system
- causes T cells to over-express genes that encode cytokines and release pro-inflammatory molecules
44
Damage to the host (Endotoxins)
1. Heat stable
2. Toxic
3. Generally similar, despite source
4. Cause general system effect: ex. fever
45
Damage to the host (Endotoxins- LPS)
- gram negative cell wall toxic to mammals
- endotoxin bc bounds to bacterium and released when the microorganism lyses
- toxic component is the lipid portion, lipid A
46
Mycotoxins
- toxins produced by fungi
- common contaminants of food crops
- contaminate water- damaged buildings
- produce hallucinogen lysergic acid (LSD)
47
Active immunity
- results from production of antibodies by immune system in response to antigen
48
Active immunity - natural
recovery from a past infection
49
Active immunity- artifical
- immune response stimulated by vaccination
50
Passive immunity
- acquired from something other than your own immune system
51
Passive immunity- natural
- transmission of IgA from mother to infact
52
Passive immunity- artifical
- direct injection of antibodies (after rabies exposure)
53
