Chapter 24

Question 1

What are factors that contribute to antimicrobial resistance:

Answer 1

• Increases in populations of immunocompromised patients
• number and complexity of invasive medical procedures
• use of antimicrobials inappropriately (broad-spectrum, excessive duration, no indications)
• survival of patients with chronic diseases.

Leading risk factors: recent use of antimicrobials, multiple medical comorbidities, recent hospitalization or other skilled health-care contact, and immunosuppression

Question 2

what is bactericidal?

Answer 2

99.9% eradication of a bacterial colony in vitro in 24 hours by an antimicrobial

Question 3

What is bacteriostatic?

Answer 3

antibiotic that kills bacteria but the result is less than 99.9% eradication in a 24-hour period

Question 4

What types of antibiotics fall under the beta-lactam superclass?

Answer 4

Penicillins
cephalosporins
carbapenems
monobactams

Question 5

How does beta-lactams work?

Answer 5

The beta-lactam ring inhibits the biosynthesis of the bacterial cell wall, specifically the peptidoglycan structure. The beta-lactam bings do the bacterial enzymes that make the cell walls and inhibits it`

Question 6

what are the four subclasses of penecillins:

Answer 6

natural penicillins
aminopenicillins
antistaphylococcal penicillins
antipseudomonal or extended-spectrum penicillins.

Question 7

What are natural penicillins effective against?

Answer 7

aerobic, gram-positive organisms (streptococcus species, some enterococcus, and some non-penicillinase-producing staphylococci [5-15%])

Pasteurella multocida, Actinomyces, Clostridium, Peptostreptococcus, and Treponema pallidum

Question 8

what is penicillinase? what bacteria releases this

Answer 8

An enzyme that hydrolyzes the beta-lactam ring of natural penicillins rendering them completely ineffective.
Staph Aureus and Haemophilus

Question 9

what is Penicillin G good for?

Answer 9

Penicillin G is reliable for treating Listeria monocytogenes

Question 10

What are aminopenicllins affective against?

Answer 10

Gram-positive organisms, including Streptococcus and Enterococcus species. They have greater activity against gram-negative bacteria because of their enhanced ability to penetrate the outer cell membrane of these organisms

Question 11

What are the two aminopenicillins?

Answer 11

AMpicillin
AMoxicillin

Question 12

what two beta-lactamse inhibitors are added to aminopenicillins?

Answer 12

clavulanic acid and sulbactam

Question 13

what are ampicillin/sulbactam and amoxicillin/clavulanate great against?

Answer 13

methicillin-susceptible Staph Aureus, Streptococcus, enterococcus, shigella, salmonella, Neisseria meningitides.

Question 14

What drugs are antistaphylcoccal penicillins?

Answer 14

Nafcillin (IV)
Oxacillin (IV)
Dicloxacillin (PO)

Question 15

what makes antistaphylococca penicillins different than other penicillins?

Answer 15

Stable in the presence of penicillinase produced by staphylococci. ineffective against Enterococcus species, Listeria, and gram-negative bacteria

Question 16

what are antistaphylococcal penicillins effective against?

Answer 16

Streptococcus species, MSSA, and Peptostreptococcu

Question 17

what are the four (4) used natural penicillines?

Answer 17

Penicillin V
Penicillin G
Procaine penicillin
benzathine penicillin

Question 18

whis the antipseudomonal penicillins

Answer 18

pipercillin/tazobactam!
good against pseudomonas, enterobacter, e.cold klebsiella, proteus mirabilus.

Question 19

what is the absorption of penicillin class

Answer 19

Oral penicillin formulations are limited due to higher-than-recommended doses causing GI distress and diarrhea. (serum concentration does not increase proportionately with higher dosages)
Penicillin V (natural) and dicloxacillin (antistaphylococcal).
Amoxicillin is more absorbed.

Question 20

what is peicillin’s distribution?

Answer 20

bounded to plasma proteins to varying degrees and well-distributed.

Question 21

can penicillins cross placenta?

Answer 21

yes

Question 22

what is the metabolism of penicillins?

Answer 22

Undergoes negligible metabolism and is excreted primarily in urine.

Question 23

what are precautions/contraindications for penicillins?

Answer 23

Allergies (~10% ; <1% true allergies)
cross-reactivity likely

Type 1 allergic reactions to cephalosporins, carbapenems, or beta-lactamase inhibitors
Zosyn may induce hemorrhagic manifestations.

Question 24

what are the ADR for penicillins?

Answer 24

Type 1 hypersensitivity (skin test!)

Gi symptoms (N/V, diarrhea)

Bacterial/fungal overgrowth of nonsusceptible organisms (with prolonged/repeat therapy).

C.diff

can be hepatotoxic (esp in HIV pts).
can be nephrotoxic (vanco + zosyn)

severe: seizures/irritability (high penicillin dose)