Sensibilidad de Paenibacillus larvae, agente causal de la loque americana de las abejas, al macrólido tilmicosina

REYNALDI F.J.; ALIPPI A.M.,. REYNALDI, F.J., LÓPEZ, A.C., DE GIUSTI, M.R. & AGUILAR O.M

Ciudad de Córdoba. Prov. Córdoba. ARGENTINA

Congreso; XIº CONGRESO ARGENTINO DE MICROBIOLOGÍA.; 2007

Asociación Argentina de Producción Animal

Effectiveness of tilmicosin against Paenibacillus larvae, the causal agent of American Foulbrood Disease of honey bees   SUMMARY American Foulbrood (AFB) of honeybees (Apis mellifera L.), caused by the Gram positive bacterium Paenibacillus larvae is the most virulent bacterial disease affecting honeybee brood.  Minimal inhibitory concentrations to tilmicosin, a macrolide antibiotic produced by chemical modification of a tylosin related compound and developed for exclusive use in veterinary medicine, were determined for twenty-three isolates of Paenibacillus larvae from different geographical origins and found to range between 0.0625 and 0.5 µg/ml, with MIC50 and MIC90 values of 0.250 mg/ml. All P. larvae strains resistant to tetracycline were susceptible to tilmicosin.  Epidemiological cut-off values were proposed to certainly identify P. larvae isolates with reduced susceptibility compared to the highest MIC value of the wild-type population. To our knowledge, this is the first report of the effectiveness of tilmicosin against P. larvae. Keywords: Paenibacillus larvae; American Foulbrood; antibiotics; tilmicosin; epidemiological cut-off values.