Spectrums of Commonly Used Agents

Question 1

What is Benzyl penicillin used against?

Answer 1

• Gram positive organisms
• The gram negative meningococci (EXCEPTION)

Best choice for iv treatment of serious pneumococcal, menigococcal and strep pyogenes infections.

Question 2

What is Amoxicilin and Ampicilin used against?

Answer 2

Better gram negative activity. Covers streptococci and some coliforms (though 20-30% of coliform organisms are resistant due to beta-lactamase)

Question 3

What is Co-amoxiclav ?

Answer 3

Combination of amoxicillin with beta-lactamase enzyme inhibitor clavulanic acid - Which extends the spectrum to cover beta-lactamase producing coliforms.

Question 4

What is flucloxacillin used for?

Answer 4

Staphylococcal infections (resistant to the beta lactamase)

Question 5

What is piperacillin used for?

Answer 5

• Broad spectrum (BOTH)
  Extended Gram Neg cover
• Enterococcus faecalis
• Anti aerobic activity (good action against serious intra abdominal infection)

Question 6

What is imipenem/ meropenem used for?

Answer 6

• Widest spectrum of all, active against most bacteria, including anaerobes.

Question 7

What are cephalosporins used for?

Answer 7

• Activity against gram negative organisms increases from the first generation. While the activity against gram positive decreases with the generations.

Question 8

What are aminoglycosides used against?And in what way are they administered?

Answer 8

• Gram negative organisms
• Staphylococci is sensitive, Streptococci is not

Parenteral use only

Question 9

Why is serum levels of Gentamicin monitored?

Answer 9

Because it could be potentially toxic.

Question 10

What are glycopeptides used for and in what way are they given?

Answer 10

• Only gram positive organisms, both aerobic and anaerobic

Question 11

What are Macrolides used for? And when?

Answer 11

• Mainly gram positives

- Used as an alternative to penicillin in patients with penicillin hypersensitivity.

Question 12

What is the clincal use of a single dose of Azithromycin?

Answer 12

Treatment of Chlamydia

Question 13

What are Quinolones used for?

Answer 13

Such as ciprofloxacin

Nearly all gram negative organisms

Can be used in the treatment of community-acquired pneumonia.

Question 14

What is metronidazole used for?

Answer 14

• effective against anaerobes, both gram positive and gram negative

Question 15

What is fusidic acid used for?

What can develop resistance easily? and waht can be done to combat this?

Answer 15

Anti-staphylococcal drug.

Staph aureus can develop resistance very readily to this agent.
Use in combination with other anti-staphylococcal drugs too.

Question 16

What infection is Trimethoprim used for?

Answer 16

Urinary infection

Question 17

What infection is co-trimoxazole used for?

Answer 17

Chest infections

Question 18

What infections are tetracyclines used for?

Answer 18

Gram Positives.

Genital tract and respiratory tract infection.

Shouldn’t be given to pregnant women or children under 12 year as they deposited in teeth and bone.

Question 19

What is clindamycin used for?

Answer 19

gram positive organisms (staphylococci and streptococci) + anaerobes

Question 20

What infection is Linezolid used in?
How is it given?
What is one negative side effect?

Answer 20

MRSA

Orally

Bone marrow supression

Question 21

What is daptomycin used for?

Answer 21

Gram positive organisms only.

May be useful for serious MRSA infections.

Question 22

What are nalidixic acid and nitrofuratoin used to treat?

Answer 22

Lower urinary tract infections

Nalidixic Acid - gram negatives aerobes
Nitrofuratoin - Most gram negative organisms and some gram positives.