Lecture 3-4: Host-Pathogen-Environment Interaction Flashcards

1
Q

Define: HOST

A

any organism that supports the survival and growth of microorganisms

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2
Q

Define: SAPROPHYTE

A

organisms that live on dead or decaying organic matter; usually not parasite but can cause disease

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3
Q

Define: PARASITE

A

general term for an organism that lives on or within another living organism

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4
Q

Define: COMMENSAL

A

an organism that lives in or on a host but does not cause disease; organism benefits but host may or may not; most of the bacteria in the intestine, skin, and mm

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5
Q

Define: ENDOGENOUS infection

A

Infection coming from commensals

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6
Q

Define: EXOGENOUS infection

A

Infection coming from environmental bacteria

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7
Q

Define: PATHOGENs

A

Those bacteria that are capable of causing disease

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8
Q

Define: PATHOGENICITY

A

The capacity of bacteria to produce disease in a host (yes/no)

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9
Q

Define: VIRULENCE

A

Variation in the pathogenicity (degree of pathogenicity: lots of disease or little amount of disease)

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10
Q

List some pre-disposing factors for infection by opportunistic pathogens.

A

Damaged tissues AND Impaired innate defense mechanisms are MOST COMMON;
Introduction to body sites where not normally found;
Disturbance of the normal flora (antibiotics);

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11
Q

Define: INFECTIVITY

A

capacity of organism to become ESTABLISHED in the host tissues;
involves: ability to penetrate tissues, survive host’s defenses, and multiply/disseminate within the host

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12
Q

Which Adaptive Immunity targets extracellular defense?

A

AMI - Antibody Mediated Immunity

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13
Q

Which Adaptive Immunity targets intracellular defense?

A

CMI - Cell Mediated Immunity

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14
Q

What must you do in order to properly treat ALL bacterial infections?

A

Identify the UNDERLYING CAUSE

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15
Q

What must bacteria be capable of to cause disease?

A

Attach, Invade, Evade, Damage/Dysfunction

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16
Q

What are virulence factors of ADHESION?

A

Pili (especially Gram -) and Adhesion factors

17
Q

What are virulence factors of INVASION?

A

Bacteria can entire either Actively OR Passively;
Passive: through damaged tissues
Active: via intact epithelium using TOXINS

18
Q

What are some virulence factors for SURVIVAL INSIDE TISSUES?

A

Anti-phagocytic molecules: M-proteins, Capsule, slime layer, biofilm;
Iron sequestration: Siderophores - bacteria MUST have Iron to survive;
Survival in protected sites: some can survive extra long in hard to reach places (lepto in kidney)
Intracellular survival: Facultative and Obligate - common of Major pathogens (S. aureus, Salmonella, Brucella)

19
Q

What is a virulence factor for survival in tissues and tissue DESTRUCTION?

A

Toxins - Evade, Damage and Dysfunction
Can directly damage, indirectly damage, cause specific dysfunction
Endotoxin vs. Exotoxin

20
Q

What table should we absolutely KNOW for toxins?

A

Table of page 35 of notes

21
Q

Is exotoxin produced by Gram (-) bacteria, Gram (+) bacteria, both or neither?

A

Both

22
Q

Endotoxin or exotoxin: Is often spontaneously diffusible.

A

Exotoxin

23
Q

Endotoxin or exotoxin: Is cell bound as part of the cell wall.

A

Endotoxin

24
Q

Endotoxin or exotoxin: Is an LPS complex containing Lipid A, core polysaccharides, and O-side chains

A

Endotoxin

25
Q

Endotoxin or exotoxin: Heat labile

A

Exotoxin

26
Q

Endotoxin or exotoxin: VERY STABLE to heat, chemicals, and storage.

A

Endotoxin

27
Q

Endotoxin or exotoxin: Potent toxins

A

Exotoxin

28
Q

Endotoxin or exotoxin: Pyrogenic (fever inducing)

A

Endotoxin

29
Q

Endotoxin or exotoxin: Highly antigenic

A

Exotoxin

30
Q

Endotoxin or exotoxin: Often readily converted to toxoids which induce neutralizing antibodies

A

Exotoxin

31
Q

Endotoxin or exotoxin: Encoded in the bacterial chromosome

A

Endotoxin

32
Q

Endotoxin or exotoxin: Synthesis determined extrachromosomally (plasmid/phage)

A

Exotoxin

33
Q

Endotoxin or exotoxin: Action is similar regardless of bacterial species of origin

A

Endotoxin

34
Q

Endotoxin or exotoxin: Different toxins have different effects

A

Exotoxin

35
Q

Endotoxin or exotoxin: Cause cell membrane damage and subsequent damage through: enzymatic digestion and formation of pores

A

Exotoxin

36
Q

Endotoxin or exotoxin: Causes widespread release of pro-inflammatory cytokines and host derived mediators

A

Endotoxin