<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>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.</p>
</abstract>

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.

Impact of Oxytetracycline on <italic>Apis mellifera</italic> Colonies: Preliminary Results on Residues and Antibiotic Resistance

Journal of Apicultural Science

This work is licensed under the Creative Commons Attribution 4.0 International License.

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

We tested two summer protocols for oxytetracycline (OTC) administration on beehives to evaluate: toxicity for the bees, residues in honey and presence of genes...

	1^st Sampling		2^nd Sampling
	5.5 months after treatment		8 months after treatment

GROUPS	Strains	ARGs	Strains	ARGs
“Long protocol”	Mannheimia haemolytica		Bacillus licheniformis
	Pantoea spp.		Serratia plymuthica
	Pasteurella pneumotropica		Klebsiella oxytoca
	Pasteurella pneumotropica/Brucella/Psychrobacter		Psychrobacter phenylpyruvicus	TET-ATET-M
	Pasteurella pneumotropica/Mannheimia/Bibersteinia	TET-M	Pasteurella spp.	TET-OTET-B
	Aeromonas-Vibrio-Pseudomonas luteola		Moraxella spp.	TET-M
	Bacillus spp. (B. thuringiensis)		Aeromonas hydrophila	TET-A
	Acinetobacter		Mannheimia haemolytica/Bibersteinia trehalosi	TET-M
			Citrobacter koseri	TET-OTET-A

	Proteus spp.		Fusobacterium spp.
	Bacillus lentus		Proteus vulgaris	TET-D
“Short protocol”	Bacillus firmus	TET-O	Aeromonas hydrophila	TET-ATET-M
	Bacillus megaterium	TET-O	Mannheimia haemolytica/Bibersteinia trehalosi	TET-O

	Bordetella spp.		Kluyvera spp.
	E. coli		Vibrio vulnificus
	Brevibacillus		Aeromonas hydrophila/caviae	TET-A
Control	Kodamaea ohmeri		Brevundimonas vesicularis/Mannheimia haemolytica/Bibersteinia trehalosi
	Paenibacillus spp.		Brevundimonas vesicularis/Mannheimia haemolytica/Bibersteinia trehalosi
	Pasteurella spp.
	Vibrio perahemolyticus

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

Article Category: Original Article

Published Online: Dec 27, 2022

Page range: 159 - 170

Received: Apr 04, 2022

Accepted: Oct 12, 2022

DOI: https://doi.org/10.2478/jas-2022-0013

Keywords
antibiotic resistance, comb honey, oxytetracycline, summer protocol, residues, toxicity

© 2022 Michela Mosca et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Fig. 1

Fig. 2

Fig. 3

Bacterial strains and ARGs found in the three groups 5.5 and 8 months after treatments

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

Article Category: Original Article

Published Online: Dec 27, 2022

Page range: 159 - 170

Received: Apr 04, 2022

Accepted: Oct 12, 2022

DOI: https://doi.org/10.2478/jas-2022-0013

Keywordsantibiotic resistance, comb honey, oxytetracycline, summer protocol, residues, toxicity

© 2022 Michela Mosca et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Fig. 1

Fig. 2

Fig. 3

Bacterial strains and ARGs found in the three groups 5.5 and 8 months after treatments

Keywords
antibiotic resistance, comb honey, oxytetracycline, summer protocol, residues, toxicity