Veterinary session

The choice of appropriate drugs used in the treatment of Rhodococcus equi infection in foals is restricted to those that exhibit the ability to cross the outer cell membrane of the macrophage, the vacuole membrane within the macrophage and to penetrate the lipid-rich cell envelope of the Rhodococcus equi bacterium.

The various available and currently used therapies used in equine practice today were reviewed to see what the most effective treatments would be. Many tests have been carried out in vitro but this does not necessarily correlate to an efficacy in vivo.

Consequently only lipophilic antimicrobials should be used to treat affected foals. Under conditions of this study, it was revealed that the highly specialised bacterium R. equi has a unique ability to evade the effect of antibiotics on a longterm basis, and therefore in recent years combination treatment was introduced. For now, the use of two antimicrobial drugs is highly successful in foals.

Rhodococcus equi is constantly adapting, and whilst it may be under relative control now, without a vaccine - this element of rapid adaptation poses a large threat to the thoroughbred racing industry in Ireland.

Key words: Antibiotics, chemoprophylaxis, Rhodococcus equi, foals, pneumonia, resistance