Topical Antibotics

Question 1

Describe Bacitracin spectrum of activity for:
(G+)
(G-)

• what is its main clinical use?

Answer 1

(G+) staph, strep, commensal skin flora.
(G-) NONE.

• GRAM POSITIVE skin INFECTIONS –> Used for prevention and trx of minor cuts/scrapes. Often formulated with polymixin B and neomycin.

Question 2

Describe PolymixinB spectrum of activity for:
(G+)
(G-)

• what is its main clinical use?

Answer 2

(G+) - NONE
(G-) - covers many gram negs. retained actiivyt agaist many multidrug resistant bacilli.

clinical usse: GRAM NEGATIVE skin INFECTIONS –> prevention and trx of minor skin infections (often in combo with bacitracin and neomycin).

Question 3

what is its main clinical use for mupirocin?

• any gram neg coverage?
• why shoudln’t mupirocin be used for longer than 7 days courses?

Answer 3

Main area of activity: G+ skin infections + spares skin flora BUT has increased resistance to staph.

• has nO GRAM NEG COVERAGE.
• cuz long term use can lead to resistance with staph.

Question 4

What is hte main area of activity for fusidic acid ?

what are its 4 main clinical uses?

Answer 4

• Gram positives only w/ decreased resistance to staph (only 1-2%).

1) impetigo
2) folliculitis (staph and strep)
3) decolonization of nares (staph aureus)
4) prophylaxis in catheter related and surgical site infections.