Journal of Apicultural Science (Dec 2022)

Impact of Oxytetracycline on Apis mellifera Colonies: Preliminary Results on Residues and Antibiotic Resistance

  • Mosca Michela,
  • Giannetti Luigi,
  • Franco Alessia,
  • Iurescia Manuela,
  • Milito Marcella,
  • Pietropaoli Marco,
  • Leto Andrea,
  • Di Ruggiero Camilla,
  • Mezher Ziad,
  • Palazzetti Massimo,
  • Gallo Valentina,
  • Croppi Sofia,
  • Macrì Salvatore,
  • Formato Giovanni

DOI
https://doi.org/10.2478/jas-2022-0013
Journal volume & issue
Vol. 66, no. 2
pp. 159 – 170

Abstract

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We tested two summer protocols for oxytetracycline (OTC) administration on beehives to evaluate: toxicity for the bees, residues in honey and presence of genes encoding for OTC antibiotic resistance in bacteria isolated from the gut of adult bees. In July 2020, eighteen healthy colonies were divided into three groups. Two OTC treatment protocols - long and short, were devised, and one group was left untreated. We did not detect any toxicity on adult bees or brood but found OTC residues in the honey of the nest up to seven months after both treatments (210.3±221.2 µg/kg after long protocol; 216.2±238.4 µg/kg after short protocol), even in the untreated group (up to the mean 75.8±173.2 µg/kg). Antibiotic resistance genes were found, even in the untreated group, possibly due to the long exposure to antibiotics. More in-depth studies should be performed to verify how the long-term persistence of antibiotics impacted the beehive during the inactive season.

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