Antimicrobials

Question 1

What is the difference between gram positive organisms and gram negative organisms? Be able to name the parts of the organism’s cell wall. What is a beta lactamase enzyme?

Answer 1

● Gram positive: many layers of peptidoglycan strands (contain penicillin binding proteins and beta lactamases
○ Beta lactamase: bacterial enzymes that inactivate drugs (THIS IS BAD)
● Gram negative: contains 2 membranes separated by periplasmic space; beta lactamases located in periplasmic space; outer membrane has aqueous channels where drugs can enter
● Gram-negative is more difficult organism to treat than gram-positive organism

Question 2

major side effect of antimicrobials

Answer 2

c diff

Question 3

Know the difference between Bacterial cell wall inhibitors, Inhibitors of bacterial cell membrane function, and inhibitors of bacterial DNA/RNA synthesis in terms of their function

Answer 3

Bacterial cell wall inhibitors (beta lactams): inhibits linking of peptide and prevents linkage of structural components of cell wall
● Inhibitors of bacterial cell membrane function: destroys cell membrane allowing escape of nutrients
● Inhibitors of bacterial DNA/RNA synthesis:
○ Fluoroquinolones: inhibit DNA gyrase enzyme preventing relaxation of supercoiled DNA (useful against gram neg)
○ Sulfonamides: interfere w/ production of folate which is necessary for production of purines and DNA

Question 4

Know the indications for Vancomycin. What is MRSA? What are the side effects of fluoroquinolones

Answer 4

Indications for Vancomycin: resistant streptococci, staphylococci, C-diff, DOC for methicillin resistant staphylococci
· MRSA: methicillin-resistant staphylococcus aureus (spreads through direct contact and can live on surface for 70+ days)
· Fluoroquinolones Side Effects: Cystic lesion in articular cartilage, tendon ruptures, long Q-T interval

Question 5

● HIV Lifecycle

Answer 5

○ Fusion of virus to the host cell surface receptor
○ Surface glycoprotein (gp120) on HIV binds to receptors on T cells, macrophages, and dendritic cells
○ Penetration and un-coating exposing RNA
○ Viral RNA converted to viral DNA by reverse transcriptase enzyme
○ Transcription of the host cell’s DNA and the viral DNA occurs and is followed by translation and production of viral proteins
○ Protease enzyme hydrolyzes the newly formed proteins into smaller units and assembles them w/ viral RNA to produce new virions
○ Budding and release of new HIV particles

Question 6

● Major HIV Drug Classifications

Answer 6

○ Fusion inhibitors, nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitors, integrase inhibitors

Question 7

What is the role of beta lactamase inhibitors?

Answer 7

● Block the beta lactamase enzymes that attack our drugs (inhibitors prevent the breakdown of these bad enzymes)