Apidologie 34 (2003) 269-279
DOI: 10.1051/apido:2003018

Oxytetracycline hydrochloride activity in honey bee larvae (Apis mellifera) following medication with various doses

Ben Alexander McKee^a, Russell David Goodman^b, Christian Saywell^c and Graham Hepworth<sup>d

a</sup>  Institute of Land & Food Resources, The University of Melbourne, Private Mail Bag 15, Ferntree Gully Delivery Centre, Vic, 3156, Australia
^b  Department of Natural Resources & Environment, Institute for Horticultural Development, Private Mail Bag 15, Ferntree Gully Delivery Centre, Vic, 3156, Australia
^c  Previously Department of Natural Resources & Environment, State Chemistry Laboratory, Corner Sneydes & South Roads, Werribee, Vic, 3030, Australia
^d  Statistical Consulting Centre, Department of Mathematics and Statistics, The University of Melbourne, Vic, 3010, Australia

(Received 11 December 2001; revised and accepted 29 October 2002)

Abstract
Four replicated experiments were conducted to determine the concentration of oxytetracycline hydrochloride (OTC) in honey bee (Apis mellifera) larvae following application of the antibiotic to honey bee colonies. In the first experiment, the mean OTC concentration was significantly greater in whole larvae than in larval guts sampled from hives on the day immediately following treatment. In two further experiments, 0.3 g, 0.5 g and 1.0 g active OTC in caster sugar was administered to single- and double-storey colonies. The mean OTC concentration was above the minimum inhibitory concentration of OTC to Melissococcus pluton for 2 to 6 days post-treatment, depending upon the dose. The daily rate of change of concentration of OTC in larvae sampled from treated colonies ranged from 0.423 to 0.672. In a fourth experiment, application of 0.3 g and 0.5 g OTC in distilled water gave equal to or higher OTC levels in larvae on the first two days post-treatment when compared to the same doses applied in caster sugar.

Key words: oxytetracycline hydrochloride / antibiotic / honey bee / European foulbrood / Australia

Correspondence and reprints: Ben Alexander McKee
    e-mail: ben.mckee@nre.vic.gov.au

© INRA, EDP Sciences, DIB, AGIB 2003