L3 Microbial Pathogenesis and Mechanisms of Virulence

Question 1

pathogenicity

Answer 1

ability to cause disease

Question 2

virulence

Answer 2

degree of damage or disease resulting from infection

Question 3

infectivity

Answer 3

likelihood of causing infection and or disease with exposure to a particular poison

Question 4

rhinovirus

Answer 4

ss + RNA, naked virion causes common cold high infectivity, low virulence

Question 5

influenza virus

Answer 5

ss - RNA, segmented enveloped causes flu moderate infectivity, greater virulence, host dependent

Question 6

ebola

Answer 6

ss -RNA, enveloped causes hemorrhagic fever high infectivity, high virulence

Question 7

endogenous acquisition transmission of microbial agents

Answer 7

escape from location where it is part of the normal microbiome

Question 8

exogenous acquisition transmission of microbial agents

Answer 8

person to person, animal to person (zoonoses), insect to person, environmental

Question 9

conceptual framework for infectious diseases

Answer 9

1. encounter 2. entry 3. spread 4. multiplication 5. damage 6. outcome

Question 10

microbial virulence factors

Answer 10

increase virulence NOT REQUIRED FOR GROWTH OUTSIDE OF THE CELL 3 main categories 1. structures involved in attachment, adherence and invasion 2. toxins involved in cell or tissue damage 3. processes involved in immune avoidance

Question 11

bacterial pili

Answer 11

aka fimbriae filamentous structures extending from the bacterial surface - sponsor initial adherence to host cells or extracellular matrix (specific or non-specific) - polymers of bacterial proteins known as pilins

Question 12

TYPE IV pili

Answer 12

specific type of bacteria pili (there are many types of pili) extend, bind, and retract promote surface motility, micro-colony, and biofilm formation, adherence of host cells and immune evasion

Question 13

flagella versus pili

Answer 13

• both are filamentous appendages - pili are shorter, increased number, and thinner - flagella composed of flagellin - pili are composed of pilins

Question 14

E coli, O157: H7 what is the H7

Answer 14

type of flagella

Question 15

T/F Only pili and not flagella are virulence factors?

Answer 15

false both are just different structures and functions

Question 16

specialized bacterial secretion systems are important for gram +/gram - bacteria

Answer 16

gram - bacteria can use type III, type IV and V systems to inject substrates into other cells

Question 17

T3SS

Answer 17

aka bacterial nanomachines specialized bacterial secretion systems inserts toxins inserts receptors

Question 18

viral attachment

Answer 18

mediated by proteins on surface of virion; proteins engage receptor on host cells and then endocytose

Question 19

capsid proteins on naked/encapsulated viruses

Answer 19

naked

Question 20

glycoprotein spikes on naked/enveloped viruses

Answer 20

enveloped

Question 21

HIV

Answer 21

• ssRNA, enveloped virus - 2-part glycoprotein spike in the viral envelope (GP120 and GP41) - bind CD4 on human T-cell - conformational change allows contact with co-receptor

Question 22

Endotoxin

Answer 22

• lipopolysaccharide (LPS) - gram - outermembrane - lipid and saccaride portion

Question 23

which portion of the endotoxin is toxic?

Answer 23

• lipid portion - potent stimulator of innate immune response

Question 24

PAMPs (pathogen-associated molecular patterns)

Answer 24

located on the pathogens

Question 25

bacterial PAMPS engage extracellular/intracellular TLRs?

Answer 25

extracellular

Question 26

viral PAMPS engage extracellular/intracellular TLRs?

Answer 26

intracellular

Question 27

exotoxins

Answer 27

- secreted toxins produced by Gram + and - bacteria - toxin genes are frequently encoded on plasmids or bacteriophages

Question 28

A + B exotoxin

Answer 28

A- active B- binding

Question 29

A + B Toxin mediated diseases

Answer 29

DTP 1. diphtheria 2. tetanus 3. pertussis (whopping cough)

Question 30

DTaP

Answer 30

vaccine for DTP

Question 31

toxoid

Answer 31

(inactivated toxins) prevents toxin mediated disease

Question 32

pore-forming toxins

Answer 32

poke holes in host cell membrane

Question 33

superantigens

Answer 33

toxins that can cause toxic shock ex. engage T-cells and antigen presenting cells (MHCII cells) in the adaptive immune system resulting in nonspecific recognition of antigens bypasses antigen specificity and leads to increased T-cells and cytokine storm

Question 34

examples of superantigens

Answer 34

staphylococcal and streptococcl

Question 35

immune avoidance by microbial pathogens

Answer 35

structures and processes important examples: 1. antigen variation 2. polysaccharide capsules 3. biofilms

Question 36

polysaccharide capsules

Answer 36

structural way of how microbial pathogens can avoid immune system extracellular component of gram + and - bacteria that can avoid phagocytosis and avoid immune recognition

Question 37

herpes viruses travel from the periphery to dorsal root ganglion and are latent in __________ and why is this important

Answer 37

sensory neurons immune avoidance by microbial pathogens

Question 38

immune avoidance by microbial pathogens structures

Answer 38

1. bacterial and fungal polysaccharide capsules 2. antigens that induce blocking antibodies 3. molecules that inactivate antibodies 4. molecules that mimic host structures and are not recognized as foreign

Question 39

immune avoidance by microbial pathogens process

Answer 39

1. antigen variation 2. avoiding immune surveillance 3. suppressing immune response

Question 40

1. Match the following bacterial structures with their primary role(s) in pathogenesis. A. Pili B. Polysaccharide capsule C. LPS D. Staphylococcal Protein A Immune avoidance Attachment to host cells Stimulates innate immune responses Thwarts phagocytosis

Answer 40

A. Attachment to host cells B. Immune avoidance; Thwarts phagocytosis C. Stimulates innate immune responses D. Immune avoidance

Question 41

2. The A subunit of Cholera Toxin has which of the following activities? Explain the consequences of this activity. A. Increases adenylate cyclase activity B. Forms pores in epithelial cell membranes C. Acts as an endotoxin D. Acts as a superantigen

Answer 41

Increases adenylate cyclase activity

Question 42

Answer 42