Characterization of Melissococcus plutonius causing European foulbrood disease in Apis cerana F.

Apis cerana F. colonies were sampled over 12 months for the study of European foulbrood (EFB) in various regions of Himachal Pradesh, India. In EFB, death of brood is generally recorded in colonies in the pupal stage, but sometimes in the prepupal and larval stages. We found that the disease affected 6.18 to 18.56% of A. cerana colonies and 7.88 to 25.33% of the brood. The bacteria were isolated from colonies showing EFB symptoms, and characterized using bacteriological, serological and molecular tools. The causal bacterium showed optimum growth in specific basal medium, pH 7.0 - 7.2 under anaerobic condition with about 1.0% CO2 at 35 degrees C. It was further characterized through positive ELISA tests and PCR assays. These studies confirmed that the colonies were infected by M. plutonius, the causal agent of EFB. The diseased colonies were treated by feeding four doses of 10 mg of ciprofloxacin ( 98% a.i.) until the disappearance of all EFB symptoms. A molecular diversity of 8 bp between M. plutonius from A. cerana and from A. mellifera was observed and submitted to the EMBL-EBI Cambridge, UK.