Typing of Pantoea agglomerans isolated from colonies of honey bees (Apis mellifera) and culturability of selected strains from honey

Pantoea agglomerans is a possible biocontrol agent against fire blight (Erwinia amylovora) and a facultative pathogen of humans. Isolates were gathered from flowers, pollen loads, honey sacs, and freshly stored nectar (FSN). Under artificial inoculation conditions, strains completely lost their culturability at 24 degrees C after 120 h of incubation in honey and 156 h in honey solution, respectively. None of tested strains could be cultivated from FSN, honey, or honey solution after 48 h at temperatures higher then 28 degrees C. At different time intervals, culturable population levels at 35 degrees C and 24 degrees C were significantly higher in blossom honey or its solution than in blossom and honeydew honey or its solution. Our results indicated that P. agglomerans is widely spread throughout honey bee's environment. Strains lost culturability after short periods of incubation in honey or honey solution. In samples of honey and royal jelly from test colonies, no culturable P. agglomerans isolates could be detected.