Lecture on Antibiotics Targeting DNA and RNA

Introductory Notes

Function: Alleviates supercoils in DNA during replication by cutting and rejoining DNA strands.
Mechanism: Cuts the phosphodiester bond to relieve tension, then reattaches the DNA fragments.

Types: Ciprofloxacin (Cipro), Levofloxacin (Levaquin), etc.
Mechanism: Stimulates cutting domain of topoisomerase and inhibits ligating domain, causing DNA fragmentation.
Effects: Bactericidal (kills bacteria).
Coverage: Mainly effective against gram-negative bacteria, some controversial coverage of gram-positive bacteria.
Uses: Treats genitourinary tract infections (e.g., pyelonephritis, prostatitis), and bone infections (osteomyelitis).

Coverage: Effective against both gram-negative (e.g., E. coli) and gram-positive bacteria (e.g., Enterococci).
Uses: Mainly for urinary tract infections (UTIs).
Mechanism: Converts to a reactive intermediate that damages DNA, RNA, proteins, and cell walls, causing bactericidal effects.

Coverage: Gram-negative, gram-positive, and protozoan infections.
Uses: Treats bacterial infections like H. pylori and bacterial vaginosis, and protozoan infections like Giardia and Entamoeba histolytica.
Mechanism: Converted by nitroreductase enzyme into an active metabolite that disrupts DNA helical structure, leading to fragmentation.

Coverage: Mainly effective against gram-positive bacteria, especially Staphylococcus aureus.
Mechanism: Forms pores in bacterial membranes, causing ion flux, depolarization, and inhibition of DNA, RNA, and protein synthesis.

Uses: Treats tuberculosis, leprosy, and Haemophilus influenzae type B.
Mechanism: Inhibits DNA-dependent RNA polymerase, preventing transcription and subsequent protein synthesis.

Covered several antibiotics targeting DNA and RNA with different mechanisms and uses.
Emphasized understanding the specific functions and applications of each antibiotic discussed.