Related Experiment Videos
Virginiamycin metabolism in cattle rumen fluid
D W Gottschall1, R Wang, D G Kingston
1Department of Drug Metabolism and Bioanalytical Services, SmithKline Beckman Animal Health Products, West Chester, PA 19380.
Drug Metabolism and Disposition: the Biological Fate of Chemicals
|November 1, 1988
Summary
Virginiamycin (VM) rapidly loses antimicrobial activity in cattle rumen fluid due to extensive metabolism of factor M. Metabolites exhibit reduced activity, impacting VM
Area of Science:
- Veterinary Pharmacology
- Microbial Metabolism
- Antibiotic Resistance
Background:
- Virginiamycin (VM) is an antibiotic used in livestock.
- Understanding VM metabolism in the rumen is crucial for its efficacy.
- Rumen fluid significantly impacts antibiotic stability and activity.
Purpose of the Study:
- To investigate the in vitro metabolism of virginiamycin (VM) in cattle rumen fluid.
- To characterize the resulting metabolites and their antimicrobial activity.
- To compare VM stability in rumen fluid versus a neutral buffer.
Main Methods:
- In vitro incubation of VM in cattle rumen fluid and neutral buffer.
- Isolation and identification of metabolites using FAB MS-MS, LC-MS, and NMR.
- Antimicrobial activity assays of VM and its metabolites.
Main Results:
- VM's antimicrobial activity decreased rapidly in rumen fluid (half-life ~8 hr) but remained stable in buffer for >24 hr.
- Four metabolites derived from the reduction of VM factor M were identified.
- VM factor S was not metabolized; metabolites showed reduced antimicrobial activity compared to factor M.
Conclusions:
- Cattle rumen fluid extensively metabolizes virginiamycin, primarily factor M, via reduction and dehydroxylation pathways.
- Metabolites of VM exhibit significantly lower antimicrobial activity than the parent compound.
- VM stability is compromised in the rumen environment, affecting its therapeutic potential.