ATC Group: S03A Antiinfectives

Chloramphenicol is a broad spectrum antibiotic which has activity against many types of Gram-positive and Gram-negative bacteria. It acts by interfering with bacterial protein synthesis. Chloramphenicol is widely distributed in body tissues and fluids and enters the cerebrospinal fluid.

Chlorhexidine is an antimicrobial agent, active against a broad spectrum of Gram-positive and Gram-negative organisms, yeasts, fungi, opportunistic anaerobes and aerobes. Chlorhexidine is mainly a “membrane-acting” agent that destroys the outer membrane of the bacteria. It is inactive on bacterial spores unless the temperatures are high.

Ciprofloxacin is a fluoroquinolone antibacterial agent. The bactericidal action of ciprofloxacin results from the inhibition of both type II topoisomerase (DNA-gyrase) and topoisomerase IV, required for bacterial DNA replication, transcription, repair and recombination.

Gentamicin is usually bactericidal in action. Although the exact mechanism of action has not been fully elucidated, the drug appears to inhibit protein synthesis in susceptible bacteria by irreversibly binding to 30S ribosomal subunits.

Neomycin is an aminoglycoside antibiotic and acts by binding to polysomes, inhibiting protein synthesis and generating errors in the transcription of the genetic code.

Polymixin B is bactericidal against a wide range of gram negative bacilli. It exerts a bactericidal effect by binding to acid phospholipids in the cell wall and membranes of the bacterium, thereby rendering ineffective the osmotic barrier normally provided by the cell membrane.

Tetracyclines are taken up into sensitive bacterial cells by an active transport process. Once within the cell they bind reversibly to the 30S subunit of the ribosome, preventing the binding of aminoacyl transfer RNA and inhibiting protein synthesis and hence cell growth.