An approach to the characterization of the honey bee hive bacterial flora

In this study we describe an approach to the characterization of the cultivable heterotrophic bacterial flora of honey bee hives. We assessed the bacterial abundance in brood combs and on hive floors at different times of the year, and identified several isolated bacteria. The number of bacteria recovered from brood combs was notably lower than the number obtained from hive floors. In addition, we observed an increase in bacteria recovered from brood comb samples from winter to summer, probably reflecting the activity of the colony during these seasons. In floor samples bacterial counts were not different among the different sampling times. Most of the identified isolates belonged to the genera Bacillus and Corynebacterium. Spores of Paenibacillus larvae subspecies larvae were only found in samples taken during summer of 2002, in accordance with an increase of American foulbrood incidence in Uruguay in the last year. The presence of several micro-organisms such as those identified as belonging to the genus Bacillus, potentially related to those that have biological control capabilities, and the differences between brood combs and floor-recovered bacteria encourage further research on the microbiology of honey bee hives and new strategies of pathogens control.