Principles and Mechanisms of Antibiotic Therapy

Question 1

Bactericidal

Answer 1

Penicillin
Cephalosporin
Aminoglycoside

Question 2

Bacteriostatic

Answer 2

Macrolides
Tetracycline
Sulfonamide
Trimethoprim

Question 3

Narrow Spectrum Drugs

Answer 3

Bactericidal, Fewer super infection, ex. Penicillin VK, First generation Cephalosporins, First generation Macrolides, Sulfa drugs;
Active against limited microbes
Adv: Less toxic to host, Fewer superinfections, Less resistance
DisAdv: Used only if causative agent known

Question 4

Extended Spectrum Drugs

Answer 4

Both, Antibiotic Associated Colitis (Clostridium Deficile) super infection, ex. Amoxicillin, Ampicillin, Clindamycin, Clarithromycin, 2+ generation Cephalosporins, Fluoroquinolines;
Greater spectrum than narrow but less than broad spectrum
DisAdv: More super infection

Question 5

Broad Spectrum Drugs

Answer 5

Bacteriostatic, Bacteria and Fungi super infection, Tetracycline;
Active against wider range of gram-pos and gram-neg
Adv: Treat mixed bacteria infections, Illness doesn’t respond to narrow agent, Less need to identify pathogen
DisAdv: More superinfections, Increase risk of drug resistance, Increase risk of childhood asthma (first year of life)

Question 6

Early (First 3 days of Infection Antibiotics)

Answer 6

Penicillin VK, Amoxicillin, Cephalexin (Or other first gen cephalosporin)
Clindamycin

Question 7

No improvement in 24-36hrs Infection Antibiotics

Answer 7

Beta-lactamase-resistant antibiotic: Dicloxacillin, Clindamycin or Amoxicillin/Clavulanic Acid (Augmentin)

Question 8

Penicillin Allergy Antibiotics

Answer 8

Clindamycin, Cephalexin (If allergy is not anaphylactoid), Clarithromycin (Biaxin)

Question 9

Late (More than 3 days of Infection Antibiotics)

Answer 9

Clindamycin, Penicillin VK Metronidazole, Amoxicillin-Metronidazole

Question 10

Penicillin Allergy

Answer 10

Clindamycin

Question 11

Reduced Uptake of Antibiotic Resistance

Answer 11

Gentamicin, Penicillin

Question 12

Active Efflux of Antibiotic Resistance

Answer 12

Tetracyclines, Beta lactams,

Question 13

Target Modification Antibiotic Resistance

Answer 13

Fluoroquinolones, Macrolides, Vancomycin (vanHAX - reprograms D-Ala-D-Ala to D-Ala-D-lac)
MRSA - Modify Penicillin Binding Proteins

Question 14

Enzymatic Inactivation Antibiotic Antibiotic Resistance

Answer 14

Hydrolysis (Penicillinase), Derivativization (Aminoglycosides, Chloramphenicol)

Question 15

Substitution with Resistant Alternative to Native Target Antibiotic Resistance

Answer 15

Methicillin (Pneumococci and Streptococci - PBP2b)

Question 16

Overproduction of Target Antibiotic Resistance

Answer 16

Trimethoprim (Overproduce dihydrofolate reductase)

Question 17

Sequestration by Protein Binding Antibiotic Resistance

Answer 17

Tetracycline by ribosomal protection proteins

Question 18

Intrinsic Resistance Antibiotic Resistance

Answer 18

Microorganism inherent insensitivity to drug, Lack of receptor for drug, Inadequate concentration of antibiotic at target site

Question 19

Drugs affected by Genetic Factors

Answer 19

Sulfonamides, Chloramphenicol, Isoniazid - G6PD deficiency, Rapid and slow acetylators
Other metabolic systems Phase I, II, P-Glycoproteins (Macrolides)

Question 20

Drugs affected by Pregnancy

Answer 20

Tetracyclines, Sulfonamides - Fetal harm