Infection of Melissococcus plutonius clonal complex 12 strain in European honeybee larvae is essentially confined to the digestive tract.

摘要: Melissococcus plutonius is an important pathogen that causes European foulbrood (EFB) in honeybee larvae. Recently, we discovered a group of M. strains are phenotypically and genetically distinct from other strains. These belong to clonal complex (CC) 12, as determined by multilocus sequence typing analysis, show atypical cultural biochemical characteristics vitro compared with CCs tested. Although EFB considered be purely intestinal infection according early studies, it unknown whether the recently found CC12 cause same pathomechanism. In this study, obtain better understanding EFB, infected (Apis mellifera) larvae per os well-characterized strain, DAT561, analyzed histopathologically. Ingested DAT561 was mainly localized midgut lumen surrounded peritrophic matrix (PM) badly affected larvae, PM epithelial cells degenerated, some bacterial were detected outside midgut. However, they did not proliferate deep tissues actively. By immunohistochemical stained anti-M. serum most DAT561-infected luminal surfaces more strongly than inside. results suggest strain essentially confined intestine. Moreover, our imply presence plutonius-derived substances diffusing into larval course infection.