Isolation and identification of Melissococcus plutonius from European foulbrood infected beehives and in vivo using of oxytetracycline for treatment

European foulbrood (EFB) is an infectious and contagious bacterial disease of honeybee larvae caused by (Melissococcus plutonius) affects primarily the young larvae (less than 48 hrs. old), and kill mainly the unsealed larvae at the age of 4 to 5 days. The aim of the present study was the isolation and diagnosis of M. plutonius that cause European foulbrood disease in beehives and used oxytetracycline in the treatment of this disease (in vivo). The infected larvae were detected by the clinical signs appears; firstly the larvae become flaccid and twisted in C- shape, the affected brood appeared yellowish, cream-colored, and later brown to almost black that can easily be removed from the cells. Sixty-nine swabs samples were collected from bees cells in Hila city. Samples were cultured on selective, differential media, and biochemical tests. All positive samples for M. plutonius, were subcultures on nutrient agar, blood agar, and yeast extract agar, and incubated at 35˚C for a week under anaerobic condition. Results declare the presence of 57 samples (82.6%) give the positive result of M. plutonius, while 12 (17.4%) samples were negative. Bacteria appear as a Gram-positive lanceolatecoccus, slender rods with a tendency to form chains. Results also showed that nine days of treatment with oxytetracycline decrease the mortality rate, the disease disappeared, and the infected larvae sealed and returned to normal. In conclusion: The study found that the EFB was decreased when oxytetracycline used as treatment