Bacteriology Part IV

Question 1

What are antimicrobials?

Answer 1

drugs that destroy microbes, prevent their multiplication, or growth, or prevent their pathogenic effect.

Question 2

Alexander Fleming discovered what?

Answer 2

Penicillin

Question 3

What is an antibiotic?

Answer 3

an antibiotic is a low molecular substance PRODUCED BY a microorganism that at a low concentration kills other microorganisms

Question 4

antimicrobial

Answer 4

a substance (natural, semisynthetic, or synthetic) that kills or inhibits another microorganism. causes little to no damage to the host

Question 5

all antibiotics are antimicrobials but not all antimicrobials are antibiotics

Answer 5

true

Question 6

What are the three types of antimicrobials?

Answer 6

1) Natural
2) Semisynthetic
3) Synthetic

Question 7

What are natural antimicrobials produced by? (true antibiotics) Examples?

Answer 7

produced by bacteria or fungus (streptomycin, penicillin, tetracycline)

Question 8

What are semisynthetic antimicrobials? Examples?

Answer 8

a natural compound thats been chemically altered

-ampicillin, amikacin

Question 9

What are synthetic antimicrobials? Examples?

Answer 9

chemically designed in a lab

-sulfonamide, enrofloxacin, marbofloxacin

Question 10

Antimicrobials are classified in 4 ways:

Answer 10

1) Chemical structure
2) Mode of action
3) Type of antimicrobial activity
4) Spectrum of antimicrobial activity

Question 11

Classification of antimicrobials: Mode of Action: Cell wall synthesis

Answer 11

B lactam antibiotics

Question 12

What are B lactam antibiotics?

Answer 12

inhibit peptidoglycan synthesis; inhibits penicillin binding proteins

Question 13

Examples of B lactam antibiotics?

Answer 13

Penicillin, ampicillin, cephalosporins

Question 14

What is B lactamase?

Answer 14

B lactamase is an enzyme active in antibiotics that can cleave B lactam antibiotic causing resistance

Question 15

Classification of antimicrobials: Mode of action: protein synthesis inhibitors:

Answer 15

1) aminoglycosides
2) Tetracyclines
3) Macrolides

Question 16

Classification of antimicrobials: Mode of action: DNA synthesis inhibitors:

Answer 16

1) Quinolones

2) Metronidazole

Question 17

Classification of antimicrobials: Mode of action: RNA synthesis inhibitors

Answer 17

1) Rifampin

2) Mupirocin

Question 18

Classification of antimicrobials: Mode of action: Folic acid synthesis inhibitors:

Answer 18

1) Sulfamides

2) Trimethoprim

Question 19

What are broad spectrum antibiotics?

Answer 19

Useful against gram positive and negative organisims

Question 20

Narrow spectrum antibacterials?

Answer 20

useful against either gram positive or negative not both

Question 21

what is Bactericidal (Suicidal)?

Answer 21

kills bacteria

Question 22

What is Bacteriostatic?

Answer 22

inhibits bacterial growth

Question 23

What is the Antimicrobial Susceptibility Test (AST)?

Answer 23

AST is a test to determine whether a bacterium is susceptible to an antimicrobial treatment

Question 24

What are the 2 types of AST available?

Answer 24

1) Disk diffusion test (kirby bauer test)

2) Broth/Agar dilution test

Question 25

What is the minimum inhibitory concentration (MIC)?

Answer 25

the minimum amount of drug required to inhibit bacterial growth

Question 26

What is the susceptibility break point?

Answer 26

the drug concentration where above it the organism is considered resistant, below it, it is susceptible to drug

Question 27

What are the three break point values?

Answer 27

Susceptible
Intermediate
Resistant

Question 28

For AST - Kirby Bauer test, what MUST you use?

Answer 28

you must use a bacterial isolate in PURE culture

Question 29

Two types of antimicrobial resistance?

Answer 29

1) Innate resistance

2) Acquired resistance

Question 30

What are the 4 ways Bacteria can block entry of antimicrobial drug?

Answer 30

1) block entry into cell
2) Inactivating enzymes
3) Altering target molecule
4) Efflux or ejection of antibiotic