By Nicola Bradbear, Peter Martin and David Wainwright, UK
In 2003, two consignments of honey being brought in to the EU from Zambia were found to contain low levels of the antibiotic streptomycin. According to EU law, honey must not contain any antibiotic residues. Tetracyclines are the only antibiotics that can be used to treat the
honey bee disease European Foulbrood, but only under veterinary control and supervision, and procedures must be followed so that any honey produced during the treatment period cannot enter the honey market.
The imported honey was harvested by beekeepers living and working in the forests that cover Zambia's remote North Western Province. It is very unlikely that these beekeepers are using antibiotics in their beekeeping. The honey is harvested from local style hives made from cylinders of bark and placed high in trees of the miombo woodland. No honeybee diseases are known, and beekeepers do not have the resources, possibility or necessity to use antibiotics in their beekeeping.
So how could streptomycin have become present in the honey? Is it possible that it is a natural constituent of honey, carried into the hive by foraging bees? Streptomycin is produced by bacteria belonging to the genus Streptomyces: these bacteria are common and widespread. Streptomycetes have been discovered in samples collected from the miombo woodland, in places frequented by bees, such as hollows in trees, water holes and leaf mould.
Early indications are that the streptomycin could indeed be occurring naturally. This has implications for honey legislation and the world honey trade, as well as for understanding of honeybee biology and honey's long-known role in health and healing.
It is also known from research that ants and Streptomycetes have a highly evolved relationship: some leaf cutter ants have white spots on their bodies these spots are colonies of a Streptomyces species, producing an antibiotic to protect the ant colony's food sources from other pathogens. Could bees also have evolved a way to harness the benefits of the antibiotic streptomycin?
Clearly, research was needed to investigate this amazing discovery, and to provide scientific data concerning the streptomycin and its possible origin. Aware that the presence of antibiotics in honey could adversely affect Zambian and other developing countries' trade in honey, Bees for Development applied for a grant from DFID (The UK Government Department for International Development), and gained support under the Business Link Challenge Fund, which enables research on issues with implications for trade with developing countries. Partner organisations working with BfD in the Project are North Western Bee Products of Zambia, Casa Mel of Mozambique, and Tropical Forest Products of Aberystwyth, UK.
Research is now underway in co-operation with Professor Elizabeth Wellington and her team at the University of Warwick, towards proving the genetic origin of the streptomycin in the Zambian honey. Results so far are providing the evidence that we need to prove that this streptomycin is occurring naturally, and preliminary data will be published in scientific research journals later in 2004. [Bees for Development Journal #72]
