Chapter 24 (Part 1) Flashcards

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1
Q

infections

A

involve the invasion and multiplication of microorganisms in body tissues

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2
Q

Infections can become clinically significant and cause
disease if…

A

→ The infection persists
→ The organism gains access to the circulatory or lymphatic systems (infection becomes systemic)

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3
Q

Types of infectious organisms

A

→ Bacteria
→ Viruses
→ Fungi
→ Parasites:
→ Helminths (Worms)
→ Protozoa

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4
Q

there are more bacterial cells in your body than…

A

human cells

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5
Q

T/F - the majority of bacteria are harmful

A

false. the majority if bacteria are beneficial

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6
Q

an area of skin as small as 1 square inch may be home to…

A

more than half a million microorganisms

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7
Q

Beneficial roles of bacteria

A
  • Produce nearly half the oxygen in the atmosphere.
  • Used to purify water and to treat sewage.
  • Used to make cheese, milk, yogurt, tea, sauerkraut, Kombucha, kefir, and sourdough bread
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8
Q

what is the function of normal flora?

A
  • Regulate immune system to tolerate food molecules
  • Prevent growth of harmful bacteria
  • Help digest food, release some minerals from food
  • Produce vitamin K and biotin
  • Increase growth of intestinal mucosal cells
  • Produce lactic acid during fermentation which lowers pH and inhibits growth of pathogenic species
  • Ferment soluble fibre/undigested carbohydrates into short-chain fatty acids
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9
Q

The plasma membrane of most bacteria is encased within a cell wall of

A

peptidoglycan

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10
Q

Peptidoglycan walls stain purple in gram-staining therefore…

A

→ Gram-positive
→ Penicillin class of antibiotics act against gram-positive bacteria by inhibiting peptidoglycans

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11
Q

The peptidoglycan layer in some bacteria is thin and covered by an outer capsule therefore…

A

→ Gram-negative
→ Outer membrane may have lipopolysaccharide (LPS) molecules (an endotoxin in gram-negative capsule).

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12
Q

under harsh conditions some bacteria from…

A

think-walled endospores

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13
Q

endospores contain…

A

core of cytoplasm with DNA and ribosomes

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14
Q

bacterias that use endospores

A

Clostridium botulinum (botulism),
C. tetani (tetanus) and Anthrax

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15
Q

Why do some bacteria make us sick?

A

Usually through making a toxin, or directly killing cells

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16
Q

LPS in gram-negative bacteria triggers the…

A

immune system

17
Q

Tetanus

A

caused by a toxin that prevents muscle relaxation

18
Q

Botulism

A

caused by a toxin that blocks neurotransmitters and prevents muscle contraction

19
Q

E. coli (strain O157:H7)

A

produces a toxin that inhibits protein synthesis and kills intestinal cells

20
Q

Other types invade cells and kill them by using up…

A

nutrients and degrading molecules for their own use

21
Q

In any drug therapy, the goal is to…

A

target specific cells or structures, while having as little effect as possible on healthy human cells

22
Q

Antibiotics may…

A

stop bacterial growth (bacteriostatic) or kill them directly (bacteriocidal)

23
Q

Antibiotic resistance

A

the ability of a bacterium to withstand the effects of an antibiotic

24
Q

If a bacterium carries several resistance genes, it is called…

A

multi-resistant or, informally, a superbug.

25
Q

Resistance genes are most commonly found on…

A

plasmids

26
Q

Resistance to antibiotic drugs can occur as the result of…

A

→ Inappropriate prescribing practices in medicine
→ Poor adherence to prescription by patient
→ Inappropriate applications of antibiotics in agriculture

27
Q

The following prescribing practices can minimize the possibility of…

A

developing antibiotic resistance

28
Q

Best Practices in Prescribing Antibiotics

A

→ Judicious use (is antibiotic needed or not?)
→ Choose appropriate class for infection
→ Appropriate dosing
→ Appropriate dosing schedule (frequency)
→ Emphasize patient’s adherence to prescription

29
Q

Opportunistic infections

A

Some organisms only cause infection when our immune system is suppressed when our normal flora is damaged, or when our skin/barriers are broken

30
Q

Opportunistic infections can occur under the following situations

A
  • Suppressed immune system
  • Altered normal flora
  • Damaged skin barrier
31
Q
A