Bacterial Pathogenesis

Front 1

What are the stages involved in bacterial infection?

Back 1

"1) Entry into body, 2) Adhesion, multiplication, colonization, #) Invasion and spread"

Front 2

What are the body's natural barriers and defense systems?

Back 2

"skin, mucus, ciliated epithelium, antibacterial secretions"

Front 3

What are passive mechanisms of entry into the body

Back 3

"inhalation, ingestion of contaminated food or water"

Front 4

What are active mechanisms of entry into the body?

Back 4

"receptor-mediated, cell mediated, trauma, arthropod bites, sexual transmission"

Front 5

What is necessary for a bacteria to colonize a site?

Back 5

"ability to adhere, growth requirements, defects in host defenses, virulence factors"

Front 6

What are adhesins?

Back 6

Bacterial lectins found at the top of pili which bind to host cell receptors

Front 7

What are invasins?

Back 7

Adhesins on bacterial cell surface which bind to integrins on host cell surface; VF enzymes which breakdown host defenses and promote growth and spread

Front 8

"Aside from adhesins and infectins, what else do bacteria use to adhere?"

Back 8

"biofilms, slime, and capsules"

Front 9

What is tissue tropism?

Back 9

bacteria can only colonize sites which meet specific growth requirements

Front 10

What is the incubation period?

Back 10

The time between infection and the development of symptoms

Front 11

What is the bacterial siderophore?

Back 11

The bacterial iron-binding protein which competes with the host for iron

Front 12

What are the types of invasins?

Back 12

"Spreading fators, hemolysins and leucocidins, coagulases, extracellular digestive enzymes, locally acting toxins, endocytosis inducers"

Front 13

What are pathogenicity islands?

Back 13

"formerly mobile gene clusters encoding adhesins, toxins, other VFs; may be turned on by single stimulus"

Front 14

How do bacteria become pathogenic?

Back 14

"non-pathogenic bacteria acquire DNA with VFs through transformation, transduction, and conjugation"

Front 15

What are the ways that bacteria survive in the host?

Back 15

"Avoid contact with phagocytes, inhibit engulfment, survive inside phagocyte, kill the phagocyte, avoid the immune system"

Front 16

How do bacteria avoid phagocytes?

Back 16

"limit inflammation, steer clear, inhibit phagocyte chemotaxis, camouflage with host molecules"

Front 17

How do bacteria inhibit engulfment?

Back 17

"polysaccharide capsules, M protein and fimbriae, surface slime, O antigen on LPS, protein A, depolymerize actin"

Front 18

How do bacteria survive inside phagocytes?

Back 18

"inhibit phagosome-lysosome fusion, resistance to lysosomal enzymes, escape phagosome before fusion"

Front 19

How do bacteria kill the phagocyte?

Back 19

"streptolysin and leucocidin cause degran. Of neutrophil, exotoxin A, intracellular pathogens kill cell"

Front 20

How do bacteria avoid the immune response?

Back 20

"tolerance, antigenic disguise, immunosuppresion, intracellular habitat, induce non-neutralizing antibody, non-specific t cell response, adsorption of antibodies by released soluble factors, antigenic variation, serotypes"

Front 21

What are exotoxins?

Back 21

species specific soluble proteins released by both gram negative and gram positive bacteria

Front 22

What are toxoids?

Back 22

detoxified toxins used for immunizing capacity

Front 23

What are A-B toxins?

Back 23

"subunit A responsible for biological activity, subunit B binds host receptors and initiates transfer of A across cell membrane"

Front 24

What is a common mechanism of A-B toxins?

Back 24

ADP ribosylation of host proteins causing inactivation

Front 25

What are some examples of A-B toxins?

Back 25

"cholera, diptheria, botulism, tetanus, anthrax"

Front 26

What does Diptheria toxin do?

Back 26

"inactivates EL-2 through ADP ribo., interfering with protein synthesis in heart, nerve tissue, and kidney"

Front 27

What toxin has a similar mechanism as Diptheria?

Back 27

exotoxin A from Pseudomonas aeruginosa

Front 28

What does cholera toxin do?

Back 28

"inactivates Gs, causing continuous cAMP synthesis blocking Na uptake and secreting chloride causing severe diarrhea and dehydration"

Front 29

Which toxins have a similar mechanism to cholera?

Back 29

enterotoxins and pertussis

Front 30

How does anthrax toxin work?

Back 30

"2 diff A subunits (lethal factor and edema factor) and 1 B subunit (protective antigen); PA binds receptor, is cleaved, and binds LF and EF; Low LF- immunsuppresion, High LF - shock, EF - immunosuppresion"

Front 31

What are two nerve toxins?

Back 31

Botullism and Tetanus

Front 32

How does Botulism work?

Back 32

blocks release of Ach

Front 33

How does Tetanus work?

Back 33

blocks muscle nerve inhibitor nerve; spastic paralysis

Front 34

What is an endotoxin?

Back 34

lipopolysaccharide coat of gram neg bacteria; not secreted till death

Front 35

What are the differences between endotoxins and exotoxins?

Back 35

"Endotoxins are not secreted until death, less potent than exotoxins, not enzymes, heat stable"

Front 36

Can endotoxins become toxoids?

Back 36

no

Front 37

How do endotoxins cause damage?

Back 37

"they don't directly, host cells cause damage in response to endotoxins"

Front 38

Describe T1SS

Back 38

"ABC transporter in IM, OMP in OM, and MFP connecting them"

Front 39

Describe T3SS

Back 39

"ONLY GRAM NEG; injectisome, similar to flag, delivers molecules directly into host cell to modulate immune and def responses; encoded on PI from up to 30 proteins"

Front 40

Describe T4SS

Back 40

"GRAM neg and pos; unique- can transfer N.A., use atp hydrolysis for energy, widespread; directly into host cell"

Front 41

Describe T5SS

Back 41

"secretes adhesins, toxins, proteases, cytolysins, T5aSS - transfers proteins with N-term passenger domain, T5bSS - secretes protein pairs, T5cSS - secretes trimeric proteins"

Front 42

Describe T6SS

Back 42

"not well characterized, encoded on PI, injectisome similar to T3SS"

Front 43

Describe T7SS

Back 43

"mostly gram pos with mycomembrane, not well characterized, encoded on PI"