Equine Science Update
Reports from the world of  equine research.
Virginiamycin and laminitis research.
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Do you have horse that suffers from laminitis? Do you give Founderguard (TM) to try to prevent it recurring? If so, researchers at London’s Royal Veterinary College would like to hear from you.

Founderguard (TM) contains the antibiotic virginiamycin. It is believed to help prevent pasture -associated laminitis by preventing an overgrowth of bacteria that occurs in the horse’s large intestine following a sudden influx of fructans.

The long-term use of in-feed antibiotics has caused concern because of the risk of bacteria becoming resistant. This is particularly so in the case of virginiamycin and led to use of the drug in animal husbandry being banned. Virginiamycin is closely related to the streptogramin antibiotic quinupristin- dalfopristin, which is the only antibiotic that is effective against certain life-threatening human infections, such as vancomycin-resistant Enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA)

The real concern is not that using virginiamycin in horses could lead to resistant equine bacteria, but that those bacteria might be able to transfer the resistance to human pathogens.

So, to limit the use of virginiamycin, it is only available in the UK under the terms of a special treatment certificate.

If it could be shown that there is little risk of human bacteria developing resistance as a result of virginiamycin being used in horses, it might be possible to persuade the government to relax the restrictions.

Dr Nicola Menzies-Gow is setting up a project at the Royal Veterinary College to investigate whether the long-term use of virginiamycin in horses with pasture-associated laminitis encourages the development of streptogramin-resistance in equine gastrointestinal enterocci.

The study plans to look for the genes for streptogramin resistance in the bacterial population of faeces of horses being fed virginiamycin. Bacteria will also be cultured in the presence of virginiamycin. The researchers hope to demonstrate that any resistance that does develop is short-lived and does not transfer to other bacteria.

To conduct the research they need faeces from horses that have been treated with virginiamycin. If you can help please contact Dr Menzies-Gow

at the Department of Veterinary Clinical Science, RVC, Hawkshead Road, North Mymms, Hertfordshire, AL9 7TA. (UK).  

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