Virginiamycin M1

Streptogramin A Antibiotic (cyclic Depsipeptide)Rx: UnknownCompound: Approved

Also known as: Ostreogrycin A, Pristinamycin IIA, Streptogramin A (virginiamycin type), Virginiamycin M, VM1

Educational Only — Not medical advice. Consult a qualified clinician before using any peptide.

Summary

Virginiamycin M1 is a streptogramin A-type cyclic depsipeptide antibiotic produced by Streptomyces virginiae. It is one of the two components of the virginiamycin complex (combined with virginiamycin S1, a streptogramin B), used primarily as a veterinary antibiotic and growth promoter in livestock. The combination of streptogramin A and B components produces synergistic bactericidal activity against Gram-positive organisms. It is related to dalfopristin, the streptogramin A component of the clinically used combination quinupristin/dalfopristin.

Mechanism of Action

Binds to the 23S rRNA of the 50S ribosomal subunit, inhibiting the elongation phase of bacterial protein synthesis by blocking the peptidyl transferase center and causing premature release of incomplete peptide chains. Acts synergistically with Virginiamycin M2 (streptogramin B component).

Routes of Administration

Oral

Goals & Uses

  • Prevention of necrotic enteritis in poultryVeterinary / Infectious DiseaseModerate
  • Growth promotion in livestockVeterinary / AgriculturalHigh
  • Treatment of Gram-positive bacterial infectionsAntimicrobialModerate

Contraindications

  • Known hypersensitivity to streptograminsAllergyHigh
  • Use in animals intended for human consumption during withdrawal periodVeterinary RegulatoryHigh

Adverse Effects

  • Selection for streptogramin-resistant enterococci (VRE cross-resistance)Antimicrobial ResistanceUnknown
  • Gastrointestinal irritationGastrointestinalUncommon

Drug Interactions

  • Virginiamycin S1 (streptogramin B component)Low

Population Constraints

  • EU livestockGeographic / RegulatoryAbsolute
  • Human useGeneral PopulationRelative

Regulatory Status

  • European UnionWithdrawnBanned as a growth-promoting feed additive in 1999 by the European Commission due to cross-resistance with quinupristin/dalfopristin (Synercid).
  • United StatesApprovedApproved: Veterinary growth promotion in poultry and swine, Prevention of necrotic enteritis in broiler chickensApproved by FDA for use as a veterinary feed additive; not approved for human therapeutic use.
  • United KingdomWithdrawnFollows EU precedent; not authorized as a growth promoter post-ban.

Virginiamycin has been approved in many countries as a veterinary antibiotic growth promoter. It was banned as a feed additive in the European Union in 1999 due to concerns about cross-resistance with quinupristin/dalfopristin (Synercid), a clinically important antibiotic. Continues to be used in some jurisdictions including the US in animal agriculture.

Evidence & Sources

No sources recorded yet.

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