Comparative MIC Enradin vs Avilamycin 2002 - 2005 - Merck Animal ...

431SCHERING-PLOUGH ANIMAL HEALTHtechnical services bulletinComparative Study of the Minimum Inhibitory Concentration –MIC of Enradin ® (Enramycin) vs. Avilamycin – against field strainsof Clostridium perfringens between 2002 and 2005Between 2002 and 2005, samples ofbroiler intestines were collected fromfarms of 12 integrators all over Japan(Hokkaido, North of Japan, Mid of Japanand Kyusyu) and sent to the KyotoDobutu Kensa Center (Kyoto AnimalClinical Center) to determine theMinimum Inhibitory Concentration –MIC for Clostridium perfringens.The number of samples were:2002: 1402003: 592004: 1032005: 62The feed additive program varied-somewere using Enradin Feed Additive, othersavilamycin and others were not usingany product.Key PointsEnradin ® Feed Additive showed during the whole study period a very strong and consistentactivity against Clostridium perfringens – low MIC’s, being always superior to avilamycin.MIC’s for Enradin Feed Additive remained low during the whole study period, while theactivity of avilamycin seemed to have deteriorated.The MIC’s for avilamycin for samples from farms using avilamycin in the feed were veryhigh, suggesting the development of bacterial resistance. In the same farms, MIC’s forEnradin Feed Additive were very low, suggesting that there is no cross resistance among thesedrugs.

Figure 3. Enradin from 2002 to 2005Number of StrainsMIC (mcg/mL)Figure 4. Avilamycin from 2002 to 2005Number of StrainsMIC (mcg/mL)

Figure 5. MIC comparison of Clostridium perfringens between Enramycin and Avilamycinin samples collected from farms using Avilamycin.Number of StrainsMIC (mcg/mL)Results• MIC results for Enradin ® Feed Additive were consistently lower throughout the study period,with no changes in sensitivity. These results indicate that resistance to enramycin has notdeveloped despite the high usage of the product in Japan – more than 30% market-share.• Samples from farms using avilamycin showed very high MIC for avilamycin, indicating thedevelopment of resistance. In the same farms, MIC’s for enramycin were very low (under 0.39μg/ml), which makes Enradin Feed Additive the product of choice in rotation programsafter avilamycin.[ Innovative [ Solutions Innovative in Solutions Poultry Health in Poultry ] Health ]Enradin is a registered trademark of Schering-Plough Animal Health Corporation.Copyright © 2006, Schering-Plough Animal Health Corporation. All rights reserved. SPAH-PBU-451