Host-Microbe Interactions

Question 1

Infection defintion

Answer 1

process by which a microbe enters into a relationship w/host; may or may not cause disease

Question 2

Infectious disease definition and types

Answer 2

diease cause by an infection with a microbe; communicable or non-communicalble

Question 3

Pathogenicity definition and types

Answer 3

the ability to cause disease; frank=in normal hosts vs. opportunistic=compromised hosts

Question 4

Virulence definition

Answer 4

degree of pathogenicity; high virulence = ability to cause disease in small numbers

Question 5

Koch’s postulates (Microbes & Disease)

Answer 5

1. specific microbes w/in lesion 2. isolate/grow microbes in vitro 3. inject cultured microbes into animals–>reproduce disease 4. specific microbes w/in lesions of diseased animals

Question 6

Major stages of all infectious diseases

Answer 6

1. Encounter 2. Entry 3. Spread 4. Multiplication 5. Damage 6. Outcome

Question 7

Encounter stage of infection characteristics

Answer 7

how agent meets host: route of infection? infectious dose?

Question 8

Entry stage of infection characteristics

Answer 8

how agent enters host: a. colonization of body surfaces b. adherence

Question 9

Spread stage of infection characteristics

Answer 9

how agent spreads from site of entry: spreading factors vs. walling-off

Question 10

Multiplication stage of infection characteristics

Answer 10

how agent multiplies w/in host: grow faster than killed

Question 11

Damage stage of infection characteristics

Answer 11

tissue damage and virulence factors: a. toxins, enzymes b. blocking defense mechanisms

Question 12

Outcome stage of infection characteristics

Answer 12

domination by microbe OR host OR coexistance

Question 13

Immune response to infectious agents that multiply inside tissue cells

Answer 13

Antibody production and kill infected cells

Question 14

Immune response to infectious agents that multiply inside phagocytes

Answer 14

Activate phagocytes to resist infection via lymphokines generated by T cells and kill infected phagocytes

Question 15

Immune response to infectious agents that multiply outside cells

Answer 15

Kill microbe extracellulary (complement-mediated lysis) or intracellularly (opsonized phagocytosis and killing); neutralize microbial toxins

Question 16

Immune response to infectious agents that multiply outside cells & attach to body surfaces

Answer 16

Coat surfaces w/antibody (primarily secretory IgA); neutralize microbial toxins

Question 17

Typical bacteria of normal flora on skin

Answer 17

1. Gram-positive cocci: Staphylcocci 2. Gram-positive rods: Corynebacteria & Propionobacterium acnes 3. Gram-negative cocci: Enteric bacilli 4. Gram-negative rods: none 5. others: none

Question 18

Typical bacteria of normal flora in oropharynx

Answer 18

1. Gram-positive cocci: a-hemolytic Streptococci 2. Gram-positive rods: Corynebacteria 3. Gram-negative cocci: Neissaria 4. Gram-negative rods: Hsemophilus, Bacteroides 5. others: Mycoplasma Spirochetes

Question 19

Typical bacteria of normal flora in large intestine

Answer 19

1. Gram-positive cocci: Enterococci 2. Gram-positive rods: Lactobacilli 3. Gram-negative cocci: none 4. Gram-negative rods: Enteric bacilli 5. others: none

Question 20

Typical bacteria of normal flora in vagina

Answer 20

1. Gram-positive cocci: Streptococci 2. Gram-positive rods: Lactobacilli 3. Gram-negative cocci: noen 4. Gram-negative rods: Bacteroides 5. others:

Question 21

Physiological importance of the microbiome (4)

Answer 21

1. effects of tissue/organ differentiation 2. production of vitamins by gut flora 3. biochemical conversions 4. Forces other pathogens to compete for colonization

Question 22

Cholera mechanism of pathogenesis

Answer 22

toxin-mediated

Question 23

Pneumococcal pneumonia mechanism of pathogenesis

Answer 23

acute inflammation caused by invasive, extracellular bacteria

Question 24

Tuberculosis mechanism of pathogenesis

Answer 24

infection by a facultative intracellular bacterium

Question 25

Rheumatic fever mechanism of pathogenesis

Answer 25

pathology mediated by an immune response