Antibacterial Drug Therapy & Beta Lactams

Question 1

How do you detect type of bacteria?

Answer 1

Gram stain

Question 1

Gram stain cells turned purple are:

Answer 1

Gram positive

Question 2

Gram stain cells turned colourless are:

Answer 2

Gram negative

Question 3

Gram positive bacteria layers consist of:

Answer 3

A thick murein layer and cytoplasmic membrane

Question 4

Definition of minimum inhibitory concentration:

Answer 4

Lowest concentration of an antibacterial drug that inhibits visible growth

Question 5

Definition of minimum bactericidal concentration:

Answer 5

Lowest concentration of antibacterial agent that is required to kill a particular bacterium

Question 6

How is MBC calculated?

Answer 6

• Taking dilutions of the MIC and sub-culturing them into antibacterial-free media
• After a set amount of time, tubes are assessed for bacterial growth
• Tube showing no bacterial growth at the lowest drug concentration indicates the MBC

Question 7

Bacteria growing close to drug on Kirby-Bauer test indicates:

Answer 7

Drug resistance

Question 8

Bacteria not growing in a wide circumference around the drug on Kirby-Bauer test indicates:

Answer 8

Sensitivity to drug

Question 9

Steps for selecting & administering antimicrobial drugs:

Answer 9

1. Identify the organism
2. Initiate treatment immediately
3. Select a drug
4. Determine dosage
5. Discuss drug safety

Question 10

When are bactericidal drugs prioritized over bacteriostatic?

Answer 10

When the immune system is compromised, or the infection is life-threatening

Question 11

Diseases requiring special consideration:

Answer 11

1. Osteomyelitis
2. Foreign bodies
3. Abscesses
4. Intracellular pathogens
5. Immunodeficiencies

Question 12

Definition of prophylactic use of a microbial drug:

Answer 12

Use of pharmacological agents for prevention as opposed to curing or treating a disease

Question 13

When is prophylactic treatment recommended?

Answer 13

• In situations where there is a high risk of serious infection following trauma such as meningitis
• When a patient’s condition predisposes them to serious infection, such as recurring UTIs
• Surgical situations

Question 14

Commonly prescribed beta-lactams:

Answer 14

Penicillin and cephalosporins

Question 15

MOA of beta-lactams:

Answer 15

Inhibition of cell wall synthesis

Question 16

How do beta-lactams inhibit cell wall synthesis?

Answer 16

Inactivating bacterial transpeptidase which results in a defective cell wall, and ultimately cell lysis

Question 17

Penicillin G spectrum of activity:

Answer 17

Narrow spectrum of activity (Gram pos bacteria, some anaerobes)
Highly effective

Question 18

What is penicillin G used to treat?

Answer 18

Serious infections w gram pos bacteria, as well as some anaerobes

Question 19

Method of administration of pen G:

Answer 19

Injected due to unstable in acidic conditions

Question 20

Method of administration of Pen V:

Answer 20

Taken orally

Question 21

Penicillins designed to be resistant to penicillinase:

Answer 21

Dicloxacillin, oxacillin, cloxacillin

Question 22

Amoxicillin spectrum of activity:

Answer 22

Targets gram pos aerobes, anaerobes, and several gram neg pathogens

Question 23

Oral bioavailability of amoxicillin:

Answer 23

80%, highest of the penicillins

Question 24

Amoxicillin is more effective when taken in combination with:

Answer 24

Penicillinase inhibitors, such as clavulanic acid

Question 25

Penicillin adverse effects:

Answer 25

hypersensitivity reactions, non-allergic skin rashes

Question 26

Main difference between cephalosporins and penicillins:

Answer 26

Cephalosporins are not susceptible to penicillinases

Question 27

Cephalosporin spectrum of activity:

Answer 27

Dependent on what generation

Question 28

Cephalexin is an example of:

Answer 28

First generation cephalosporin

Question 29

What are first gen cephalosporins used to treat?

Answer 29

Gram pos aerobes, anaerobes, and some medically important gram neg aerobes such as e. coli

Question 30

Cefuroxime is an example of:

Answer 30

Second generation cephalosporin

Question 31

What are second gen cephalosporins used to treat?

Answer 31

Anaerobes, many gram neg bacteria

Question 32

Cefotaxime is an example of :

Answer 32

Third gen cephalosporin

Question 33

MOA of third gen cephalosporins:

Answer 33

Readily cross BBB

Question 34

What are third gen cephalosporins used to treat?

Answer 34

Gram neg aerobes

Question 35

What are fourth gen cephalosporins used to treat?

Answer 35

reserved for life-threatening infections - Rapidly penetrate gram neg bacteria - Active against beta-lactamase producing bacteria