Definition

Noun: 1. An antibiotic substance: Gramicidin is an antibiotic compound that is naturally produced by certain soil bacteria. It is primarily used as a topical antiseptic to treat localized infections caused by Gram-positive bacteria. It is not typically used systemically (inside the body).

Usage

Gramicidin is used almost exclusively in a medical or pharmaceutical context. It is commonly found in combination with other antibiotics (like neomycin and polymyxin B) in topical ointments, creams, or solutions designed to prevent or treat minor skin infections, wounds, or eye infections.

Examples

• The doctor prescribed an ointment containing gramicidin for the superficial skin infection.
• Gramicidin is effective against many Gram-positive organisms but is not absorbed safely for internal use.
• This first-aid cream combines bacitracin, neomycin, and gramicidin to provide broad-spectrum protection.

Advanced Usage

• Mechanism of Action: In microbiology and pharmacology, gramicidin is noted for its unique mechanism. It forms channels in bacterial cell membranes, disrupting ion gradients and ultimately killing the cell.
• Historical Context: Gramicidin was one of the first antibiotics to be isolated and commercially produced, playing a significant role in early antibiotic research.

Variants and Related Words

• Gramicidin S: A specific, cyclic variant of gramicidin that is also used as a topical antibiotic.
• Gram-positive (adj.): A classification of bacteria that have a thick peptidoglycan layer in their cell walls, which are the primary target of gramicidin.

Synonyms

• Topical antibiotic
• Antimicrobial agent
• Antiseptic (in its specific use context)

Notes

• Gramicidin is distinct from many other antibiotics because it is a peptide (a small protein-like chain of amino acids).
• Its use is strictly limited to external application due to its toxicity to human cell membranes if ingested or injected.

Noun

1. an antibiotic produced by a soil bacterium; used chiefly as an antiseptic in treating local infections produced by Gram-positive bacteria