Antimicrobial Chemotherapy

Question 1

Give examples of penicilins that are commonly used

Answer 1

Amoxicilin, flucloxacilin, co-amoxiclav, benzylpenicillin/penicillin V and piperacillin/tazobactam

Question 2

What are the main uses of benzylpenicillin/penicillin V?

Answer 2

Soft tissue, pneumococcal, meningococcal, gonorrhoea and syphilis

Question 3

What are the main uses of amoxicilin?

Answer 3

UTI and RTI

Question 4

What is the main use of flucloxacilin?

Answer 4

S. aureus

Question 5

What are the main uses of co-amoxiclav?

Answer 5

UTI, RTI, soft tissue infections and surgical wound infections

Question 6

What is the main use of piperacillin/tazobactam?

Answer 6

Neutropenic sepsis (IV)

Question 7

Give examples of commonly used cephalosporins

Answer 7

Cefradine (1st), cefuroxime (2nd), ceftriaxone/cefotaxime (3rd), ceftazidime (3rd) and ceftaroline/ceftobipirole (4th) - anti MRSA

Question 8

What are the main uses of cefradine?

Answer 8

UTIs and soft tissue infection

Question 9

What are the main uses of cefuroxime?

Answer 9

UTI, RTI and surgical prophylaxis

Question 10

What are the main uses of ceftriaxone/ cefotaxime?

Answer 10

Hospital infections e.g. bacteraemia, pneumonia and abdo sepsis

Question 11

What are the main uses of ceftazidime?

Answer 11

Pseudomonal infections in hospital and in cystic fibrosis

Question 12

What are the main uses of ceftaroline/ ceftobipirole?

Answer 12

Skin and soft tissue infections (+ IE resistant to other treatment)

Question 13

What is the most common aminoglycoside and what is it used for?

Answer 13

• Gentamicin

- Serious gram negative infections e.g. bacteraemia, endocarditis and neutropenic sepsis

Question 14

Give examples of commonly used macrolides

Answer 14

Clarithromycin, erythromycin and azithromycin

Question 15

What are the main uses of clarithromycin and erythromycin?

Answer 15

Resp infection, soft tissue infection (if penicillin allergic) and STDs

Question 16

What is the main use of azthromycin?

Answer 16

Chlamydia

Question 17

Give examples of commonly used quinolones?

Answer 17

Ciprofloxacin, levofloxacin and moxifloxacin

Question 18

What are the main uses of ciprofloxacin?

Answer 18

Complicated UTI, complicated hospital pneumonia and some GI infections

Question 19

What is the main use of levofloxacin/moxifloxacin?

Answer 19

2nd or 3rd line agent for pneumonia

Question 20

Give examples of commonly used glycopeptides

Answer 20

Vancomycin and teicoplanin

Question 21

What are the main uses of vancomycin and teicoplanin?

Answer 21

MRSA, alternative to penicillin (allergy) and C. diff (oral)

Question 22

What are the 4 main mechanisms of bacterial resistance?

Answer 22

• Enzymatic inactivation of the drug
• Modified targets for drugs
• Reduced permeability to drug
• Efflux of drug

Question 23

Describe how binary fission works

Answer 23

• DNA replicates
• Cell elongates
• Divides in 2
• Creates 2 identical bacteria

Question 24

How can plasma mediated resistance occur?

Answer 24

Conjugation - transfer resistance gene to other species

Question 25

List the medically important resistant organisms

Answer 25

MRSA, VRE, ESBL, CPE and clostridium difficile

Question 26

Which infections can MRSA cause?

Answer 26

Severe invasive infections e.g. osteomyelitis and endocarditis

Question 27

What is VRE resistant to and what infection can it cause?

Answer 27

- Vancomycin | - Endocardities: esp. in patients with prosthetic devices

Question 28

Which antibiotics are ESBL resistant to?

Answer 28

Beta lactam antibiotics - cephalosporins

Question 29

Which factors influence antibiotic resistance?

Answer 29

- Antibiotic use by medical professions, vets, farming etc. - Patients surviving longer with more medical conditions and hospital contact - More invasive procedures and prosthetic devices - Increased bed pressure encouraging spread of resistant organisms

Question 30

What are the reasons for failure of antibiotic therapy?

Answer 30

- Inadequate dose/route - Non-compliance - Bacterial walled off in abscess cavity - Foreign bodies e.g. surgical implants/prosthesis - Poor penetration of drug to site of infection

Question 31

Which antibiotics have good biofilm activity?

Answer 31

Rifampicin, daptomycin and ceftobiprole

Question 32

List the points of the antibiotic stewardship

Answer 32

- Using the right antibiotic for the right indication for the right duration of time - Use only if suspected/proven bacterial infection - Review prescriptions and stop ASAP - Limit use of broad spectrum blind antibiotic therapy to seriously ill patients

Question 33

When should IV antibiotics be switched to oral?

Answer 33

- Able to swallow and tolerate fluids - Temp 36-38 for at least 48hrs - Heart rate <100 for 12 hrs - WCC: 4-12x10^6L

Question 34

Which health conditions would mean you wouldn't switch IV antibiotics to oral?

Answer 34

Endocarditis, meningitis, staph aureus bacteraemia, immunosuppression, bone/joint infection, deep abscess, CF and prosthetic infection

Question 35

What may antivirals be used for?

Answer 35

Prophylaxis, pre-emptive therapy, overt disease and suppressive therapy

Question 36

Which antivirals can be used for HSV and VZV?

Answer 36

Aciclovir, valaciclovir, famciclovir and foscarnet

Question 37

How does aciclovir work?

Answer 37

It is converted to ACV-TP which competitively inhibits and inactivates HSV-specific DNA polymerase (prevents further viral DNA synthesis without interrupting the cell)

Question 38

When would antivirals be used to treat CMV?

Answer 38

HIV patients, CMV retinitis, colitis. transplant patients, pneumonitis and neonates with symptomatic congenital CMV infection

Question 39

Which antivirals can be used to treat chronic hepatitis B?

Answer 39

- Tenofovir - Adefovir - Entecavir - Larnivudine - Emtricitabine - Telbivudine

Question 40

Which antivirals can be use to treat chronic hepatitis C?

Answer 40

Pegylated interferon alpha and ribavirin +/- telaprevir or boceprevir