Spotlight on Antibiotics

Question 1

Urgent bacterial threats

Answer 1

Question 2

Serious bacterial threats

Answer 2

Question 3

Concerning bacterial threats and watch list

Answer 3

Question 4

4 mechanisms of antibiotic resistance

Answer 4

Modifications of the Antibiotic Molecule
Decreased Antibiotic Penetration and Efflux
Changes in Target Sites
Resistance Due to Global Cell Adaptations

Question 5

What are 4 antibiotic stewardship practices?

Answer 5

1.) to measure antibiotic prescribing
2.) to improve antibiotic prescribing by clinicians and use by patients so that antibiotics are only prescribed and used when needed
3.) to minimize misdiagnoses or delayed diagnoses leading to the underuse of antibiotics
4.) to ensure that the right drug, dose, and duration are selected when an antibiotic is needed

Question 6

What kills sensitive organisms so that number of viable organisms fall rapidly after exposure

Answer 6

Bactericidal

Question 7

What inhibits growth of bacteria but does not kill them?

Answer 7

Bacteriostatic

Question 8

What type of antibiotic’s agent is active against a single species or limited group of pathogens?

Answer 8

narrow-spectrum

Question 9

What type of antibiotic’s agent is active against a wide range of pathogens?

Answer 9

broad-spectrum

Question 10

Which type of antibiotic’s agent falls in between (intermediate) narrow and broad?

Answer 10

extended-spectrum

Question 11

Penicillin V: type, administration, adverse effects and what it treats?

Answer 11

Narrow-spectrum antibiotic
Typically administered in an oral suspension
Adverse effects include GI upset, nausea, vomiting, diarrhea, and rash. In rare instances can cause severe hypersensitivity reactions.
Considered the drug of choice for Group A streptococcal pharyngitis

Question 12

Mechanism of action of antibiotics

Answer 12

All beta-lactam antibiotics interfere with bacterial cell wall synthesis

Inhibition of bacterial transpeptidase (also called penicillin-binding protein) which inhibits peptidoglycan cross-linking making cell wall synthesis impossible

Generally confers bactericidal activity

Question 13

Penicillin V: Dose

Answer 13

Dosed by weight for adults and children
People over 27 kg: 300 mg TID or 600 mg BID PO for 10 days
People 27 kg or under: 40 mg/kg/day divided BID or TID for 10 days with a maximum daily dose of 750 mg.

Question 14

Amoxicillin: type, side effects?

Answer 14

An extended-spectrum penicillin
Essentially a modified version of penicillin that results in greater activity against additional gram-negative bacteria
Generally well tolerated but can cause the same adverse effects as penicillin V
Typically used more often as it is more palatable than penicillin V

Question 15

Amoxicillin dose.

Answer 15

Dosed by body weight for all patients
50 mg/kg once daily or divided BID PO for 10 days with a maximum daily dose of 1000 mg.

Question 16

Cephalosporins class: type, structure?

Answer 16

A very large group of antibiotics
The different generations are used to define their antimicrobial spectrum
Have greater structural diversity which is more resistant to beta-lactamases and increases their range of antimicrobial activity

Question 17

Cefadroxil: type, what it is used for, side effects.

Answer 17

A first-generation cephalosporin
May be used if treatment failure with penicillin or in individuals with nonimmediate hypersensitivity to penicillins
Adverse effects include GI upset, nausea, vomiting, diarrhea, hypersensitivity (some cross-reactivity with penicillins)

Question 18

Cefadroxil dose

Answer 18

Adults: 1 g/day PO as a single dose or divided BID for 10 days

Question 19

Cephalexin: type, side effects

Answer 19

A first-generation cephalosporin
Adverse effects include GI upset, nausea, vomiting, diarrhea, hypersensitivity (some cross-reactivity with penicillins) and may also be used if treatment failure with penicillins or in individuals with nonimmediate hypersensitivity to penicillins
Also available as a suspension

Question 20

Cephalexin dose.

Answer 20

Adults: 500 mg BID PO for 10 days
Children: 40 mg/kg/day divided BID PO for 10 days with a maximum daily dose of 1000 mg.

Question 21

Protein synthesis inhibitors

Answer 21

Prokaryotic ribosomes are composed of a 30S and 50S subunit

Eukaryotic mRNA translation proteins are far more complex than those in prokaryotic cells

Question 22

What do macrolides do? What does it interfere with?

Answer 22

Inhibit peptidyl transferase which functions to link amino acids together in the growing peptide chain

Also interferes with translocation (movement of the nucleotide from the A position to the P position to allow for reading the next spot on the mRNA)

Confers bacteriostatic activity

Question 23

Azithromycin uses, side effects

Answer 23

An alternative for patients who are allergic to penicillin

Less likely than other macrolide antibiotics to interact with other drugs

Adverse effects include GI upset, nausea, vomiting, diarrhea, rash, QTc interval prolongation.

type of macrolide

Question 24

Azithromycin dose, benefits?

Answer 24

Adults: 500 mg PO for one day, then 250 mg PO daily for 4 days

Children: 12 mg/kg PO for 5 days with a maximum daily dose of 500 mg

ONLY 5 days

Question 25

Clarithromycin: uses, side effects, drug interactions?

Answer 25

An alternative for patients who are allergic to penicillin

Adverse effects include GI upset, nausea, vomiting, diarrhea, rash, QTc interval prolongation.

Also available as a suspension

Increases the levels of some common drugs like atorvastatin, lovastatin, simvastatin, and prednisone

type of macrolide

Question 26

Clarithromycin dose.

Answer 26

Adults: 250 mg BID PO for 10 days

Children: 15 mg/kg/day divided BID PO for 10 days with a maximum daily dose of 500 mg.

Question 27

Linosamides class uses, problems?

Answer 27

Interfere with translocation like macrolides but do not inhibit peptidyl transferase

Approximately 4 times more likely to cause Clostridium difficile infections compared to other antibiotics

Generally bacteriostatic but can be bactericidal at high doses

Question 28

Clindamycin: alternative for what, treatment for what, side effects?

Answer 28

An alternative for patients who are allergic to penicillin
May be used for treatment in symptomatic patients with multiple, recurrent episodes of pharyngitis
Commonly causes diarrhea as an adverse effect. Increased risk of C. difficile colitis

Question 29

Clindamycin dose

Answer 29

Adults: 300 mg TID PO for 10 days
Children: 21 mg/kg/day divided TID PO for 10 days with a maximum daily dose of 900 mg

Question 29

Group A streptococcus pharyngitis who should take antibiotics for it?

Answer 29

Antibiotic therapy is most beneficial for people who are at high risk of developing acute rheumatic fever and who have confirmed streptococcal infection

Watchful waiting may be appropriate in patients at low risk for acute rheumatic fever as antibiotics have a minimal impact on the natural course of group A streptococcal pharyngitis

Question 30

Which of the following antibiotics is suitable for use in a patient with an immediate hypersensitivity reaction to penicillin?

A. Amoxicillin
B. Cephalexin
C. Cefadroxil
D. Azithromycin

Answer 30

Azithromycin

Amoxicillin is a class of penicillin

Cephalexin and Cefadroxil can be used in non-immediate hypersensitivity (non-anaphylaxis) but there is a risk involved with immediate hypersensitivity.

Question 31

Which 2 antibiotics are in the penicillin class?

Answer 31

Penicillin V and amoxicillin

Question 32

What are the 2 antibiotics in the cephalosporin class?

Answer 32

cefadroxil and cephalexin

Question 33

Which 2 classes of antibiotics disrupt the bacterial cell wall synthesis, having a bactericidal effect?

Answer 33

penicillin class and cephalosporin class