Module 6

Question 1

Chemotherapeutic agents

Answer 1

Chemicals used in the treatment of disease

Question 2

Antimicrobial agent

Answer 2

A type of chemotherapeutic agent used specifically for the treatment of infectious diseases

Question 3

Antibiotic

Answer 3

A chemical substance produced by a microorganism that in low concentrations, inhibits the growth of other microorganisms
Includes chemicals only partly produced by microorganisms and those totally reproduced by chemical synthesis

Question 4

Broad spectrum antibiotics

Answer 4

Affect a wide variety of microorganisms
Affects both GPO and GN bacteria
Must have action against some GN Enterobacteriaceae

Question 5

Bactericidal

Answer 5

Antimicrobial agent actually kills the bacteria

Question 6

Bacteriostatic

Answer 6

Antimicrobial agent only prevents the bacteria from multiplying
The body’s defence mechanisms can often rid the body of bacteria once multiplication has been stopped

Question 7

On an immunosuppressed pt would we use bactericidal or bacteriostatic antibiotics?

Answer 7

Bactericidal - immunosuppressed patients do not have sufficient WBCs to kill the bacteria on their own

Question 8

Modes of action of antimicrobial agents

Answer 8

1. inhibitors of cell wall synthesis
2. inhibitors of protein synthesis
3. inhibitors of DNA and RNA synthesis
4. inhibitors of cell membrane function
5. inhibitors of other metabolic processes

Question 9

Why is the bacterial cell wall a main target site for antimicrobial action?

Answer 9

Human cells do not have a cell wall so destructive action may be confined to bacteria
Peptidoglycan (the target site) is unique to the bacterial cell wall

Question 10

Beta-lactam

Answer 10

The core component of all antibiotics that inhibit cell wall synthesis (combine with Penicillin Binding Proteins in the cell wall)

Question 11

Penicillin binding proteins

Answer 11

Enzymes in the bacterial cell wall that combine with beta-lactam
Involved in the final stages of cross link formation in peptidoglycan synthesis

Question 12

How to beta-lactam antibiotics work?

Answer 12

Beta-lactam combines with penicillin binding proteins in the cell wall, which prevents cross link formation (in peptidoglycan in the cell wall). In turn the cell wall weakens, eventually ruptures, and bacterial cell death follows

Question 13

Why are GN bacteria more resistant to beta-lactam antibiotics?

Answer 13

They have a protective outer covering of lipid-containing material around the cell wall

Question 14

Two major groups of beta-lactam antibiotics

Answer 14

Penicillins

Cephalosporins

Question 15

Spectrum of natural penicillins

Answer 15

Narrow, mainly Gram positive

Question 16

Clinical use of natural penicillins

Answer 16

Pen G is acid labile, therefore not taken orally
Pen V is more acid stable and can be taken orally
Often given in combination with other drugs

Question 17

Does class concept apply for natural penicillins?

Answer 17

Yes

Question 18

Class concept

Answer 18

The test results for one antibiotic apply to all antibiotics of that class

Question 19

Examples of beta-lactamase resistant penicillins

Answer 19

Oxacillin, Methicillin, Cloxacillin (most commonly used)

Question 20

Spectrum of beta-lactamase resistant penicillins

Answer 20

Narrow, Gram positive

Mainly used for the treatment of Staph infections

Question 21

Bacterial resistance to beta-lactamase resistant penicillins

Answer 21

Bacteria can alter the PBPs in their cell wall, so the antibiotic can’t attach

Question 22

Does class concept apply for beta-lactamase resistant penicillins?

Answer 22

Yes (Oxacillin usually used in lab, as it is more stable)

Question 23

Examples of extended spectrum penicillins

Answer 23

Ampicillin, amoxicillin (more commonly used)

Question 24

Does class concept apply for extended spectrum penicillins?

Answer 24

Yes

Question 25

2 groups of anti-pseudomonal penicillins + examples

Answer 25

``` Carboxy penicillins (carbenicillin, ticarcillin) Ureidopenicillins (azlocillin, mezlocillin, piperacillin) ```

Question 26

Why were anti-pseudomonal penicillins developed?

Answer 26

Primarily to kill ampicillin resistant bacteria, especially Pseudomonas aeruginosa

Question 27

Clinical use of anti-pseudomonal penicillins

Answer 27

$$$ Expensive, use is reserved for bacteria that are resistant to other antibiotics Often used for pseudomonal infections Works with aminoglycosides

Question 28

Does class concept apply for anti-pseudomonal penicillins?

Answer 28

No

Question 29

Imipenem spectrum

Answer 29

Broad - widest spectrum available

Question 30

Vancomycin spectrum

Answer 30

Narrow, Gram positive

Question 31

Polymixins spectrum

Answer 31

Narrow, Gram negative

Question 32

Spectrum of sulfonamides

Answer 32

Broad

Question 33

Examples of 1st generation cephalosporins

Answer 33

Cephalothin, Cefazolin, Cephalexin

Question 34

Examples of 2nd generation cephalosporins

Answer 34

Cefaclor, Cefamandole, Cefoxitin, Cefuroxime

Question 35

Examples of 3rd generation cephalosporins

Answer 35

Cefixime, Cefotaxime, Ceftizoxime, Cefoperazone, Ceftazidime, Ceftriaxone

Question 36

Examples of 4th generation cephalosporins

Answer 36

Cefipime, Cefpirome

Question 37

What generation cephalosporin is Cefipime in?

Answer 37

4th generation

Question 38

What generation cephalosporin is Cefaclor in?

Answer 38

2nd generation

Question 39

What generation cephalosporin is Cefazolin in?

Answer 39

1st generation

Question 40

What generation cephalosporin is Ceftazidime in?

Answer 40

3rd generation

Question 41

What generation cephalosporin is Cefoxitin in?

Answer 41

2nd generation

Question 42

What generation cephalosporin is Cefpirome in?

Answer 42

4th generation

Question 43

Cotrimoxazole is a combination of which two antimicrobials

Answer 43

Sulfonamide and Trimethoprim

Question 44

Nitrofurantoin clinical uses

Answer 44

Used to treat urinary infections - blood concentrations too low Bright yellow compound

Question 45

Negative side effects of Chloramphenicol

Answer 45

Gray syndrome - fatal condition in infants; ashen grey cyanosis, listless and weak as Chloramphenicol levels increase (it cannot be excreted by infants) Aplastic anemia - fatal irreversible marrow aplasia Dose-related marrow depression

Question 46

How do we monitor patients on Chloramphenicol?

Answer 46

Daily white blood cell counts

Question 47

Nitrofurantoin spectrum

Answer 47

Broad

Question 48

Vancomycin clinical use

Answer 48

Large molecule - won't cross blood-brain barrier - can't treat CNS infections Reserved for MRSA, C. diff, resistant strains of Enterococcus

Question 49

Chloramphenicol - bacteriostatic or bactericidal?

Answer 49

Bacteriostatic

Question 50

1st gen cephalosporins - bacteriostatic or bactericidal?

Answer 50

Bactericidal

Question 51

Vancomycin - bacteriostatic or bactericidal?

Answer 51

Bactericidal

Question 52

Sulfonamides - bacteriostatic or bactericidal?

Answer 52

Bacteriostatic

Question 53

Fluoroquinolones - bacteriostatic or bactericidal?

Answer 53

Bactericidal

Question 54

Polymixins - bacteriostatic or bactericidal?

Answer 54

Bactericidal

Question 55

Natural penicillins mode of action

Answer 55

Inhibition of cell wall synthesis

Question 56

Trimethoprim example

Answer 56

Cotrimoxazole (SXT)

Question 57

Trimethoprim clinical use

Answer 57

UTIs | Combined with sulfonamide

Question 58

Trimethoprim spectrum

Answer 58

Broad

Question 59

Trimethoprim mode of action

Answer 59

Prevents synthesis of folic acid from PABA through competitive inhibition

Question 60

Sulfonamides examples

Answer 60

Cotrimoxazole (SXT) | Sulfamethoxazole

Question 61

Sulfonamides clinical use

Answer 61

Inexpensive Some enter CNS UTIs More effective when given with trimethoprim

Question 62

Sulfonamides mode of action

Answer 62

Prevents synthesis of folic acid from PABA through competitive inhibition

Question 63

Polymixins clinical use

Answer 63

Used in culture media and in discs | Nephrotoxicity, neurotoxicity

Question 64

Polymixins mode of action

Answer 64

Inhibition of cell membrane function causing membrane leakage

Question 65

Quinolones: Metronidazole example

Answer 65

Flagyl

Question 66

Quinolones: Metronidazole clinical use

Answer 66

Anaerobes | Protozoan parasitic infections (Giardia, Trichomonas)

Question 67

Quinolones: Metronidazole mode of action

Answer 67

Inhibition of DNA replication | Bactericidal

Question 68

Quinolones: Nalidixic acid mode of action

Answer 68

Inhibition of DNA replication | Bactericidal

Question 69

Quinolones: Nalidixic acid spectrum

Answer 69

Broad

Question 70

Fluoroquinolones examples

Answer 70

Ciprofloxacin, norfloxacin

Question 71

Fluoroquinolones spectrum

Answer 71

Broad

Question 72

Fluoroquinolones clinical use

Answer 72

Irreversible cartilage and skeletal damage | Unusable for patients under 18, pregnant or nursing

Question 73

Aminoglycosides examples

Answer 73

Kanamycin, gentamycin, tobramycin, amikacin, netilmicin, spectinomycin

Question 74

Aminoglycosides clinical use

Answer 74

Ineffective in anaerobes Synergistic with beta-lactam antibiotics Affected by Ca ang Mg Toxic to kidneys and eighth cranial nerve

Question 75

Aminoglycosides spectrum

Answer 75

Broad

Question 76

Aminoglycosides mode of action

Answer 76

Inhibition of protein synthesis | Bactericidal

Question 77

Tetracyclines examples

Answer 77

Terramycin, aureomycin, doxycycline, minocycline

Question 78

Tetracyclines clinical use

Answer 78

"Exotics" - Chlamydia, Mycoplasma, rickettsial infections | Deposits in bone structure - not for use in children

Question 79

Tetracyclines spectrum

Answer 79

Broad | Resistance is common

Question 80

Tetracyclines mode of action

Answer 80

Inhibition of protein synthesis | Bacteriostatic

Question 81

Chloramphenicol spectrum

Answer 81

Broad

Question 82

Chloramphenicol mode of action

Answer 82

Inhibition of protein synthesis | Bacteriostatic

Question 83

Erythromycin mode of action

Answer 83

Inhibition of protein synthesis

Question 84

Erythromycin spectrum

Answer 84

Narrow, gram positive

Question 85

Erythromycin clinical use

Answer 85

S. pyogenes infections when penicillin allergy is present | "Exotics" - Chlamydia, Mycoplasma, Legionella

Question 86

Vancomycin mode of action

Answer 86

Inhibition of cell wall synthesis | Bactericidal

Question 87

Imipenem mode of action

Answer 87

Inhibition of cell wall synthesis | Bactericidal

Question 88

Aztronam spectrum

Answer 88

Narrow, gram negative

Question 89

Aztronam mode of action

Answer 89

Inhibition of cell wall synthesis | Bactericidal

Question 90

Cephalosporins spectrum

Answer 90

Broad

Question 91

3rd generation cephalosporins clinical use

Answer 91

Crosses blood-brain barrier easier than 1st generation

Question 92

Beta-lactamase inhibitors examples

Answer 92

Clavulanic acid | Sulbactam