Topic 1-5 (Lecture 5)

Question 1

What has the most impact on bacterial disease prevention?

Answer 1

Sanitation and Education

Question 2

What are ancient/modern methods of sanitation?

Answer 2

• slightly alcoholic beverages, having settlements near streams
• Using natural preservation methods to keep food good (ex. spices, salt and vinegar, dehydration)
• Getting fresh air
• Dental and hand hygiene
• Quarantine

Question 3

What is an example of quarantining?

Answer 3

Sanatoriums for disease like TB or Leprosy (isolation of contagious individuals for treatment)

Question 4

What is the main goal of education (for disease)

Answer 4

Inform the public on behavioral adaptations that can decrease risk/spread of bacteria

Question 5

Why is education good?

Answer 5

-It’s cost-effective

Question 6

What are the 2 levels that education can work at?

Answer 6

Personal - ex. teeth-brushing, hand sanitizer use, etc.

Political - building adequate sanitation systems

Question 7

What are bacteriophages?

Answer 7

Viral agents that recognize and lyse bacterial pathogens

Question 8

What are pros to using bacterophages?

Answer 8

Chepaer to make than antibiotics

Mutations can be beneficial

Question 9

What are cons to using bacterophages?

Answer 9

Mutations can be detrimental/make viruses unsuitable for therapy
Research costs are the same in terms of cost when compared to antibiotic research

Question 10

What are the 2 traits that are desirable in bacterophages?

Answer 10

Specificity - only targets bacteria that is causing problems (shouldn’t disrupt microbiota that much)

Lysis - Viruses that are lytic are desired (can be lytic (killing) or lysogenic (not killing))

Question 11

What are antiseptics?

Answer 11

Chemical agents that are applied to LIVING tissue to kill or inhibit the growth of microorganisms

Question 12

What are disinfectants?

Answer 12

Chemical agents used on INANIMATE objects to kill microorganisms

Question 13

What is the difference between antiseptics and disinfectants?

Answer 13

One is for living tissue (antiseptics), on is for inanimate objects (disinfectants)

Question 14

What are chemotherapeutic agents?

Answer 14

Chemical agents used to control infectious diseases internally in a body

Question 15

What are chemotherapeutic agents that work on bacteria called?

Answer 15

Antibiotics

Question 16

What are the two types of antibiotics?

Answer 16

Bactericidal

Bacteriostatic

Question 17

What do bactericidal antibiotics do?

Answer 17

KILL bacteria

Question 18

What do bacteriostatic antibiotics do?

Answer 18

INHIBIT bacterial growth

Question 19

What is the difference between natural, semi-synthetic and synthetic antibioitics?

Answer 19

Natural - come from natural sources (ex. mold)
Semi-synthetic - chemically modified natural antibiotics (such that it isn’t “natural”)

Synthetic - What it means

Question 20

What is usually more sensitive to antibiotics: Gram-positive or gram-negative?

Answer 20

Gram positive

Question 21

What are the two “spectrums” of antibiotics?

Answer 21

Broad and narrow spectrum

Question 22

What is the difference between broad and narrow spectrum antibiotics?

Answer 22

Broad acts on both gram +ve and gram -ve bacteria, whereas narrow spectrum antibiotics only act on a single group of organisms

Question 23

What are optimal attributes of chemotherapeutic agents?

Answer 23

Soluble in body fluids w/ good penetration to infection site

A broad spectrum of activity (i.e. activity against broad range of bacteria)

Low frequency of resistance development

Low rate of breakdown in body

Low toicity

Well-tolerated in human body

Non-allergenic

Question 24

What are some ways how antibiotics work?

Answer 24

1) Interfere w/ bacterial cell wall biosynthesis by inhibiting peptidoglycan (only bacteria have this)
2) Destabilize cell membrane (potentially dangerous/toxic to humans, last resort)
3) interfere w/ protein synthesis by binding to ribosome and inhibiting function (doesn’t affect humans due to difference in eukaryote ribosomes)
4) interfere w/ DNA gyrase activity, disrupting replication (different in bacteria vs eukaryote)
5) interfere w/ DNA-directed RNA polymerase activity (bacterial RNAPol is different enough from humans to be OK)
6) Interfere w/ folic acid metabolism (bacteria-specific metabolic processes)

Question 25

What is antibiotic resistance?

Answer 25

Acquired ability of microorganisms to resist the effects of an antibiotic which it is normally sensitive to

Question 26

What is vertical gene transfer?

Answer 26

Transfer of mutations (ex. antibiotic resistance) to offspring during mitosis

Question 27

What are the three mechanisms of horizontal gene transfer?

Answer 27

Conjugation
Transduction
transformation

Question 28

What is conjugation (horizontal gene transfer)?

Answer 28

Transfer of plasmid DNA via cell-cell contact

Question 29

What is transduction (horizontal gene transfer)?

Answer 29

Bacterial virus picks up DNA from resistant bacteria and transfers it to sensitive cell (can be plasmid or chromosomal DNA)

Question 30

What is transformation (horizontal gene transfer)?

Answer 30

DNA w/ resistance gene taken from environment

Question 31

Are all resistance traits from mutation?

Answer 31

No, some bacteria is natural resistant (ex. lack the structural target of antibiotic; have natural physiological features such as pumps that diminish antibiotic effects)

Question 32

Why does exposure to antibiotics can result in resistant bacteria?

Answer 32

Antibiotics apply a population pressure that selects for resistant bacteria to thrive (think ecology). It is NOT exposure that results in resistance

Question 33

What are problems with antibiotics now?

Answer 33

They are overused

• Antibiotics used for wrong illnesses (incorrect prescription or too acessible)
• People don’t complete antibiotic course -> less-than-lethal exposure promotes antibiotic resistance to develop
• Antibiotic misuse in agriculture (potential for zoonosis)

Question 34

What are some consequences of antibiotic use?

Answer 34

• One may experience side-effects
• Microbiota may also be affected (could lead to opportunistic pathogens to infect)

*Microbiota usually re-establish itself after finishing antibiotic course

Question 35

What is the problem with superbugs?

Answer 35

We cannot use antibiotics as effectively against them (the current ones) due to resistance, and developing new antibiotics are expensive

Question 36

How do biofilms contribute to antimicrobial resistance?

Answer 36

1) EPS matrix impede penetration of anitmicrobial agents
2) O2 and nutrient gradient results in some cells being less metabolically active -> metabolically active bacteria are more affected by antibiotics; thus less metabolically active = less affected by antibiotics
3) Persister cells just stay alive for some reason - hard to kill

Question 37

Approaches to anti-biofilm therapy?

Answer 37

1) Interfere w/ EPS
2) Interfere w/ biofilms from forming
3) Target autoinducers - no autoinducers, no signal; no signal, no quorum sensing and thus no biofilm formation

Question 38

How do vaccines prevent disease? *Review

Answer 38

Prevent disease by training a secondary immune response

Question 39

What materials are used to make vaccines?

Answer 39

• killed virulent bacteria
• avirulent mutants of pathogenic bacteria
• outermost components of microoganisms
• toxoids (toxins that have been deactivated)

Question 40

What are the 2 forms of immunity? *Review

Answer 40

Active and passive

Question 41

What is the difference between active and passive immunization? *Review

Answer 41

Active immunization relies on induction of immune response (trained response); passive immunization relies on injecting pre-formed antibodies (cannot train response)