Virginiamycin S1
Also known as: Ostreogrycin B (related), Pristinamycin IA (analog), Staphylomycin S1, Streptogramin B, Virginiamycin B, Virginiamycin S, VS1
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Summary
Virginiamycin S1 is the streptogramin B component of the virginiamycin antibiotic complex, used primarily as a veterinary feed additive to control Gram‑positive bacterial infections and as a growth promoter in livestock.
Mechanism of Action
Binds to the 50S ribosomal subunit of bacteria, inhibiting protein synthesis; synergistic with streptogramin A component (virginiamycin M1).
Routes of Administration
Goals & Uses
- Gram-positive bacterial infection treatmentAntimicrobialModerate
- MRSA and resistant Gram-positive infectionsAntimicrobial ResistanceLow
- Livestock growth promotionVeterinary/agriculturalHigh
- Ribosomal biology research toolResearchHigh
- Antibacterial activityInfectious DiseaseHigh
Contraindications
- Concurrent use with drugs metabolized by CYP3A4Drug InteractionModerate
- Human useClinicalHigh
- Hypersensitivity to streptogramin antibioticsAllergyHigh
Adverse Effects
- HepatotoxicityHepaticUncommonLiver injury or dysfunction
- Arthralgia/myalgiaMusculoskeletalUncommon
- Injection site reactionsLocalCommon
- Gastrointestinal disturbanceGastrointestinalCommon
- Antibiotic resistance developmentMicrobialUnknown
Drug Interactions
- Other protein synthesis inhibitorsModerate
- CYP3A4 substrates (e.g., cyclosporine, tacrolimus, statins)High
- WarfarinModerate
- Chloramphenicol / lincosamidesModerate
Population Constraints
- PregnancyReproductive SafetyRelative
- Hepatic impairmentOrgan FunctionRelative
- Poultry and swineSpeciesRelative
- Human patientsClinicalAbsolute
- Pediatric populationAgeRelative
Regulatory Status
- European UnionWithdrawnBanned as growth promoter; restricted veterinary use.
- United StatesUnapprovedNot approved for human use; limited veterinary use under specific conditions.
- United KingdomWithdrawnSimilar to EU restrictions.
Virginiamycin as a combination product (M1 + S1) has been used as a veterinary/agricultural growth promotant in several countries but has faced bans or restrictions in the EU due to concerns over cross-resistance with quinupristin/dalfopristin. The isolated S1 component alone is not an approved pharmaceutical agent in any major jurisdiction.
Evidence & Sources
No sources recorded yet.
Frequently Asked Questions
What is Virginiamycin S1?
Virginiamycin S1 is the streptogramin B component of the virginiamycin antibiotic complex, used primarily as a veterinary feed additive to control Gram‑positive bacterial infections and as a growth promoter in livestock.
What is Virginiamycin S1 used for?
Virginiamycin S1 is educationally associated with: Gram-positive bacterial infection treatment, MRSA and resistant Gram-positive infections, Livestock growth promotion, Ribosomal biology research tool, Antibacterial activity. Educational only — not medical advice.
How is Virginiamycin S1 administered?
Recorded routes of administration: Oral, Subcutaneous.
What are the potential side effects of Virginiamycin S1?
Reported adverse effects include: Hepatotoxicity, Arthralgia/myalgia, Injection site reactions, Gastrointestinal disturbance, Antibiotic resistance development. This list is not exhaustive — consult a qualified clinician.
Who should avoid Virginiamycin S1?
Recorded contraindications: Concurrent use with drugs metabolized by CYP3A4, Human use, Hypersensitivity to streptogramin antibiotics. Consult a qualified clinician before use.