Target: Pristinamycin targets bacterial protein synthesis at the 50S ribosomal subunit. Pristinamycin IA is a macrolide-like component that inhibits protein synthesis. The two components have a synergistic antibacterial action. The spectrum of action is similar to erythromycin. Virginiamycin complex contains two streptogramin antibiotics, virginiamycin M1 (75%) and virginiamycin S1 (25%).

In Vitro Activity: Pristinamycin demonstrates antibacterial activity against Gram-positive bacteria including Staphylococcus and Streptococcus species. The synergistic combination of components provides potent antimicrobial activity. The compound inhibits bacterial protein synthesis. Detailed MIC values against clinical isolates are available from the primary literature.

In Vivo Activity: Pristinamycin is used clinically for the treatment of staphylococcal and streptococcal infections. It demonstrates in vivo efficacy in animal models of bacterial infection and has been used in clinical practice. Residue determination studies have been conducted in pig tissues.

In Vitro Enzyme/Receptor Binding Protocol: Antibacterial susceptibility testing is performed using standard broth microdilution or agar dilution methods according to CLSI guidelines. Bacteria are cultured in appropriate media and incubated with serial dilutions of Pristinamycin. MIC values are determined as the lowest concentration inhibiting visible growth.

In Vitro Cell-Based Assay Protocol: Bacterial cultures are grown in appropriate media and treated with Pristinamycin at various concentrations. Bacterial growth inhibition is measured by optical density or colony counting. Time-kill curves may also be performed to assess bactericidal activity. Synergy studies evaluate the combined effect of the two components.

In Vivo Animal Assay Protocol: Animal models of staphylococcal or streptococcal infection are used to evaluate Pristinamycin efficacy. The compound is administered via appropriate routes, and survival, bacterial load, and infection resolution are measured. Residue determination studies have been conducted in pigs following dietary supplementation.

Absorption, Distribution and Excretion
This article describes the results of residue determination of the growth promoters carbadox, tylosin, and virginiamycin in pig kidneys, liver, and muscle during feeding trials, as well as the analytical methods used. Residues of the carbadox metabolite quinoxaloline-2-carboxylic acid were detected in pig liver after a 30-day withdrawal period following dietary supplementation with 20 mg/kg carbadox. No residues were detected in muscle with zero withdrawal time. The limits of detection for both tissues were 0.01 mg/kg. Residues of virginiamycin and tylosin were not detected in pigs after dietary supplementation with 50 mg/kg and 40 mg/kg virginiamycin, respectively, even with zero withdrawal time. Tylosin residues of 0.06 mg/kg or less were detected in the liver and kidneys of pigs fed 200 or 400 mg/kg tylosin and slaughtered within 3 hours of the last feeding.

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Metabolism/Metabolites
Reduction of virginiamycin S with sodium borohydride yields allodihydrovirginiamycin S and n-dihydrovirginiamycin S. Reduction of the toluenesulfonylhydrazone of virginiamycin S with sodium cyanoborohydride yields deoxyvirginiamycin S. These compounds have lower activity than virginiamycin S. Like virginiamycin S, they enhance the activity of virginiamycin M1.
Virginiabutyrolactones (VBs) are one of the butyrolactone self-regulators in Streptomyces genus and serve as the main signal for triggering virginiamycin in Streptomyces virginiae. During biosynthesis, Streptomyces (S. virginiae) possesses a specific binding protein, BarA. To elucidate the in vivo function of BarA in the VB-mediated virginiamycin biosynthesis signaling pathway, we constructed two barA mutant strains (strains NH1 and NH2) through homologous recombination. In strain NH1, a 99 bp EcoT14I fragment within the barA gene was deleted, resulting in a 33-amino acid residue in-frame deletion, including the second helix of a possible helical-turn-helical DNA-binding motif. Strain NH1 exhibited the same growth rate on both solid and liquid media as wild-type Streptomyces, and its morphological behavior remained largely unchanged, indicating that the VB-BarA pathway is not involved in the morphological regulation of Streptomyces. In contrast, virginiamycin production in strain NH1 occurred 6 hours earlier than in the wild-type strain, demonstrating for the first time that BarA actively participates in the regulation of virginiamycin production and suggesting that BarA plays a repressive role in virginiamycin biosynthesis. In strain NH2, the EcoNI-SmaI fragment within the barA gene was replaced by an inverted neomycin resistance cassette, resulting in a C-terminal truncated BarA that retained the complete helical-turn-helical domain. In the NH2 strain and in plasmid strains integrating both the complete and mutant barA genes, virginiamycin production was suppressed regardless of the presence of virginiamycin (VB), indicating a dominant advantage of mutant BarA with the intact DNA-binding domain over wild-type BarA. These results further support the hypothesis that BarA is a repressor of virginiamycin synthesis and demonstrate that the helix-turn-helix motif is crucial for its function. In the NH1 strain, VB synthesis was also suppressed, suggesting that BarA is a pleiotropic regulatory protein that controls not only virginiamycin synthesis but also the biosynthesis of autoregulatory proteins. Previous studies have shown that the central loop of the 23S rRNA V domain is located within the peptidyl transferase domain of the ribosome. This enzymatic activity is inhibited by several antibiotics, including type A (virginiamycin M or VM) and type B (virginiamycin S or VS) synergists, which have synergistic effects in vivo. This study investigated the ability of VM and VS to alter the accessibility of 23S rRNA base pairs to chemical reagents in the ribosome. VM protects rRNA bases A2037, A2042, G2049, and C2050. Furthermore, when the ribosome is incubated with both components of virginiamycin, base A2062, which was originally protected only by VS, becomes reactive with dimethyl sulfate (DMS). These altered reactivity of different rRNA bases located in or near the central loop of the V domain to chemical reagents provide experimental evidence for VM-induced ribosome conformational changes.

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Pharmacokinetics: Pristinamycin has molecular formula C71H84N10O17 and molecular weight 1349.5. As a large molecule antibiotic complex, it has limited oral bioavailability and is typically administered parenterally. Residue studies in pigs showed that virginiamycin residues were not detected after dietary supplementation with 50 mg/kg.

Toxicity: Pristinamycin has been used clinically with an established safety profile. Common adverse effects include gastrointestinal disturbances and allergic reactions. Comprehensive toxicity data are available from clinical use. The compound is for research use only and is not approved for general therapeutic use in all regions.

Appl Environ Microbiol. 2015 Oct;81(19):6621-36.

Virginiamycin is a streptomycin antibiotic, similar to pristaprine and quinuprine/dalfopristin. It is a combination of pristaprine IIA and virginiamycin S1. Virginiamycin is used in the fuel ethanol industry to prevent microbial contamination and in livestock for the prevention and treatment of infections. According to a USDA study, antibiotic use can reduce feed costs for piglets by up to 30%. Virginiamycin is a class of streptomycin-associated peptide antibiotics isolated from Streptomyces virginiana and other Streptomyces bacteria. Virginiamycin consists of two main components: virginiamycin M1 and virginiamycin S1. These drugs bind to ribosomes and inhibit their assembly, thereby preventing protein synthesis. These antibiotics are effective against Gram-positive bacteria and are primarily used in veterinary clinics. (NCI04) A mixture of antibiotics originally isolated from Streptomyces pristinaspiralis. It is a mixture of streptomycin group A compounds (prilistatin IIA and IIB) and streptomycin group B compounds (prilistatin IA, prilistatin IB, prilistatin IC).
See also: Virginiamycin (note moved to).

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Additional Information: Pristinamycin has CAS number 11006-76-1. It is also known as Virginiamycin antibiotic complex, NSC-246121, Antibiotic 899, Founderguard, RP-7293, and Streptogramin. Pristinamycin is a mixture of two components that have a synergistic antibacterial action. Pristinamycin IA is a macrolide with a spectrum similar to erythromycin. Virginiamycin complex contains virginiamycin M1 (75%) and virginiamycin S1 (25%). For research use only.

C71H84N10O17

1349.5

1348.601

11006-76-1

11006-76-1; 21411-53-0; 23152-29-6;

11979535

Reddish-yellow powder

170-178ºC

4.992

6

19

7

98

2640

0

CCC1C(=O)N2CCCC2C(=O)N(C(C(=O)N3CCC(=O)CC3C(=O)NC(C(=O)OC(C(C(=O)N1)NC(=O)C4=C(C=CC=N4)O)C)C5=CC=CC=C5)CC6=CC=CC=C6)C.CC1/C=C\C(=O)NC/C=C\C(=C/C(CC(=O)CC2=NC(=CO2)C(=O)N3CCC=C3C(=O)OC1C(C)C)O)\C

MVTQIFVKRXBCHS-YWAQVZITSA-N

InChI=1S/C43H49N7O10.C28H35N3O7/c1-4-29-40(56)49-21-12-17-30(49)41(57)48(3)32(23-26-13-7-5-8-14-26)42(58)50-22-19-28(51)24-31(50)37(53)47-35(27-15-9-6-10-16-27)43(59)60-25(2)34(38(54)45-29)46-39(55)36-33(52)18-11-20-44-36;1-17(2)26-19(4)9-10-24(34)29-11-5-7-18(3)13-20(32)14-21(33)15-25-30-22(16-37-25)27(35)31-12-6-8-23(31)28(36)38-26/h5-11,13-16,18,20,25,29-32,34-35,52H,4,12,17,19,21-24H2,1-3H3,(H,45,54)(H,46,55)(H,47,53);5,7-10,13,16-17,19-20,26,32H,6,11-12,14-15H2,1-4H3,(H,29,34)/b;7-5-,10-9+,18-13+/t25-,29-,30+,31+,32+,34+,35+;19-,20-,26-/m11/s1

N-((6R,9S,10R,13S,15aS,22S,24aS)-22-benzyl-6-ethyl-10,23-dimethyl-5,8,12,15,17,21,24-heptaoxo-13-phenyldocosahydro-12H-pyrido[2,1-f]pyrrolo[2,1-l][1]oxa[4,7,10,13,16]pentaazacyclononadecin-9-yl)-3-hydroxypicolinamide compound with (12Z,6R,7R,8E,13Z,15E,17S)-17-hydroxy-6-isopropyl-7,15-dimethyl-32,33-dihydro-31H-5-oxa-11-aza-1(4,2)-oxazola-3(1,5)-pyrrolacycloicosaphane-8,13,15-triene-2,4,10,19-tetraone (1:1)

RP-7293; NSC-246121; RP7293; NSC246121; Virginiamycin antibiotic complex;RP 7293; NSC 246121; Antibiotic 899; Founderguard; Mikamycin; RP 7293; Stapyocine; Streptogramin;Virginiamycin Complex

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)