Evaluation of oxytetracycline in the prevention of American foulbrood in bee colonies

In this paper, we presented the procedure of artificial infection of bee colonies with American Foulbrood by the spores of Panibacillus larvae ( P. larvae). Bee colonies were treated with oxytetracycline that was applied in a patty and sugar syrup. The symptoms and the course of the disease within the bee colony were monitored. Our research included 20 bee colonies divided in three experimental and one control group. Every bee colony consisted of 2000 young worker bees and a young breeder queen. After laying of first eggs three experimental groups were infected with spore-suspension of P. laervae at concentration 2x10(9) spore/ml. The development of the disease was monitored under the following experimental conditions: Experimental group I did not receive antimicrobial therapy, Groups II and III were given antibiotics in a sugar syrup and extender patty, respectively. In the first experimental group the first clinical signs were observed on day 25. while vegetative form of P. larvae was detected on day 12. Treatment with oxytetracycline in the second and third group delayed the manifest disease until day 47.