Tyrothricin

• R02AB02
• D06AX08
• S01AA05

Antibiotics

> 3000 mg · kg -1 ( LD50, mouse, oral)

Template: Infobox chemical / molecular formula search available

Tyrothricin is a blend of two of antibacterial polypeptides ( called antimicrobial peptides), gramicidin and tyrocidine, which are formed endotoxinartig by the anaerobic spore-forming Bacillus aneurinolyticus (formerly Bacillus brevis ). The mixture contains 70 to 80% and 20 to 30 % Tyrocidine gramicidins. The area of ​​influence comprising mainly Gram-positive bacteria as well as some Gram-negative bacteria and various fungi, such as Candida albicans.

Tyrothricin is assigned due to its structure and synthesis for the group of polypeptide antibiotics, and actinomycin, bacitracin, and polymyxins belong among others.

However, the group of polypeptide antibiotics is very different in their mode of action. For example, actinomycin and double-stranded DNA intercalated with bacitracin engages the murein biosynthesis.

Tyrothricin similar mode of action to strong antimicrobial peptides ( or host defense peptides ), as they are known in eukaryotes (such as defensin and cathelicidin ). Because of this similarity, they are now increasingly also assigned to this group ( non- ribosomally synthesized antimicrobial polypeptides).

Effect

Tyrothricin is an anti-microbial polypeptide, which damages the cell membrane of various micro-organisms irreversible.

As a mixture of two active substances tyrothricin acts in two ways on the microbial cell wall:

Tyrocidin becomes embedded in the cell membrane of microorganisms and thus destroys their function. The exact location and mechanism are unknown.

Gramicidin forms cation-selective channels in the cell membrane, the membrane can pass through the monovalent charged cations (such as potassium, sodium). Here, among other things, the ion gradient between the cytoplasm and extracellular medium is canceled.

Tyrothricin acts dose-dependent bacteriostatic or bactericidal to the following microorganisms:

Show the development of resistance that tyrothricin shows a continued high effectiveness even against Staphylococcus aureus strains with multiple antibiotic resistance (MRSA ). It also has no cross -resistance with polymyxin B and colistin.

The reason for this sustained efficacy and lack of development of resistance is suspected in the direct and double attack on the cell membrane of microorganisms. To develop resistance, pathogens would change the nature and composition of their cell membranes. A complicated and ( in view of evolution ) are very complex process.

Because of this consistently high tyrothricin effect is reinforced arrives with its active ingredients gramicidin and tyrocidine in recent years, again in the view of the research.

Application

Tyrothricin is only used locally. In this context, the antibiotic in the form of throat lozenges for sore throat and pain with swallowing, with pharyngeal and laryngeal inflammation as well as inflammation of the oral mucosa and gums is employed.

In addition tyrothricin is for ameliorating treatment of small -scale, shallow, little moist skin wounds with bacterial superinfection with tyrothricin - susceptible pathogens such as cracks, scratches, abrasions, used.

Side effects

For local use in general, hypersensitivity reactions to the drug, such as burning or itching of the skin or mucous membrane have been observed. There are currently no long-term studies on the effect of pregnancy and lactation.

In systemic absorption may occur strong nephrotoxic and neurotoxic side effects.

Trade names

Tyrosur (D)

• With cetylpyridinium chloride and lidocaine: Citropain (CH)
• With benzalkonium chloride and benzocaine: Dorithricin (D, A)
• With cetrimonium and lidocaine: Lemocin (D, A, CH)
• With cetylpyridinium chloride and oxybuprocaine: Mebucaine (CH)
• With lidocaine and lysozyme: Mebucasol (CH), Sangerol (CH)
• With cetylpyridinium chloride and antipyrine: Otothricinol (CH)
• With acetylcysteine ​​, phenylalanine, lidocaine and taurine: Solmucaine (CH)
• With dequalinium and lidocaine: Tyroqualin (CH)

Numerous generic (A, CH)