Chapter 24 (Part 1)

Question 1

infections

Answer 1

involve the invasion and multiplication of microorganisms in body tissues

Question 2

Infections can become clinically significant and cause
disease if…

Answer 2

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

Question 3

Types of infectious organisms

Answer 3

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

Question 4

there are more bacterial cells in your body than…

Answer 4

human cells

Question 5

T/F - the majority of bacteria are harmful

Answer 5

false. the majority if bacteria are beneficial

Question 6

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

Answer 6

more than half a million microorganisms

Question 7

Beneficial roles of bacteria

Answer 7

• 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

Question 8

what is the function of normal flora?

Answer 8

• 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

Question 9

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

Answer 9

peptidoglycan

Question 10

Peptidoglycan walls stain purple in gram-staining therefore…

Answer 10

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

Question 11

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

Answer 11

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

Question 12

under harsh conditions some bacteria from…

Answer 12

think-walled endospores

Question 13

endospores contain…

Answer 13

core of cytoplasm with DNA and ribosomes

Question 14

bacterias that use endospores

Answer 14

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

Question 15

Why do some bacteria make us sick?

Answer 15

Usually through making a toxin, or directly killing cells

Question 16

LPS in gram-negative bacteria triggers the…

Answer 16

immune system

Question 17

Tetanus

Answer 17

caused by a toxin that prevents muscle relaxation

Question 18

Botulism

Answer 18

caused by a toxin that blocks neurotransmitters and prevents muscle contraction

Question 19

E. coli (strain O157:H7)

Answer 19

produces a toxin that inhibits protein synthesis and kills intestinal cells

Question 20

Other types invade cells and kill them by using up…

Answer 20

nutrients and degrading molecules for their own use

Question 21

In any drug therapy, the goal is to…

Answer 21

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

Question 22

Antibiotics may…

Answer 22

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

Question 23

Antibiotic resistance

Answer 23

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

Question 24

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

Answer 24

multi-resistant or, informally, a superbug.

Question 25

Resistance genes are most commonly found on…

Answer 25

plasmids

Question 26

Resistance to antibiotic drugs can occur as the result of…

Answer 26

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

Question 27

The following prescribing practices can minimize the possibility of…

Answer 27

developing antibiotic resistance

Question 28

Best Practices in Prescribing Antibiotics

Answer 28

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

Question 29

Opportunistic infections

Answer 29

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

Question 30

Opportunistic infections can occur under the following situations

Answer 30

• Suppressed immune system
• Altered normal flora
• Damaged skin barrier