Dataset Information

Dose-dependent impact of oxytetracycline on the veal calf microbiome and resistome.

ABSTRACT: BACKGROUND:Antibiotic therapy is commonly used in animal agriculture. Antibiotics excreted by the animals can contaminate farming environments, resulting in long term exposure of animals to sub-inhibitory levels of antibiotics. Little is known on the effect of this exposure on antibiotic resistance. In this study, we aimed to investigate the long term effects of sub-inhibitory levels of antibiotics on the gut microbiota composition and resistome of veal calves in vivo. Forty-two veal calves were randomly assigned to three groups. The first group (OTC-high) received therapeutic oral dosages of 1?g oxytetracycline (OTC), twice per day, during 5 days. The second group (OTC-low) received an oral dose of OTC of 100-200??g per day during 7 weeks, mimicking animal exposure to environmental contamination. The third group (CTR) did not receive OTC, serving as unexposed control. Antibiotic residue levels were determined over time. The temporal effects on the gut microbiota and antibiotic resistance gene abundance was analysed by metagenomic sequencing. RESULTS:In the therapeutic group, OTC levels exceeded MIC values. The low group remained at sub-inhibitory levels. The control group did not reach any significant OTC levels. 16S rRNA gene-based analysis revealed significant changes in the calf gut microbiota. Time-related changes accounted for most of the variation in the sequence data. Therapeutic application of OTC had transient effect, significantly impacting gut microbiota composition between day 0 and day 2. By metagenomic sequence analysis we identified six antibiotic resistance genes representing three gene classes (tetM, floR and mel) that differed in relative abundance between any of the intervention groups and the control. qPCR was used to validate observations made by metagenomic sequencing, revealing a peak of tetM abundance at day 28-35 in the OTC-high group. No increase in resistance genes abundance was seen in the OTC-low group. CONCLUSIONS:Under the conditions tested, sub-therapeutic administration of OTC did not result in increased tetM resistance levels as observed in the therapeutic group.

SUBMITTER: Keijser BJF

PROVIDER: S-EPMC6339435 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

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Dose-dependent impact of oxytetracycline on the veal calf microbiome and resistome.

Keijser Bart J F BJF Agamennone Valeria V van den Broek Tim J TJ Caspers Martien M van de Braak Adri A Bomers Richard R Havekes Mieke M Schoen Eric E van Baak Martin M Mioch Daniël D Bomers Lonneke L Montijn Roy C RC

BMC genomics 20190119 1

<h4>Background</h4>Antibiotic therapy is commonly used in animal agriculture. Antibiotics excreted by the animals can contaminate farming environments, resulting in long term exposure of animals to sub-inhibitory levels of antibiotics. Little is known on the effect of this exposure on antibiotic resistance. In this study, we aimed to investigate the long term effects of sub-inhibitory levels of antibiotics on the gut microbiota composition and resistome of veal calves in vivo. Forty-two veal cal ...[more]

PMID: 30660184

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Dataset Information

Dose-dependent impact of oxytetracycline on the veal calf microbiome and resistome.

Publications

Dose-dependent impact of oxytetracycline on the veal calf microbiome and resistome.

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