Selection and transfer of an IncI1-tet(A) plasmid of Escherichia coli in an ex vivo model of the porcine caecum at doxycycline concentrations caused by crosscontaminated feed.
J Appl Microbiol
; 123(5): 1312-1320, 2017 Nov.
Article
em En
| MEDLINE
| ID: mdl-28799283
ABSTRACT
AIMS:
The aim of this study was to investigate the effect of subtherapeutic intestinal doxycycline (DOX) concentrations (4 and 1 mg l-1 ), caused by cross-contamination of feed, on the enrichment of a DOX-resistant commensal Escherichia coli and its resistance plasmid in an ex vivo model of the porcine caecum. METHODS ANDRESULTS:
A DOX-resistant, tet(A)-carrying, porcine commensal E. coli strain (EC 682) was cultivated for 6 days in the porcine caecum model under different conditions (0, 1 and 4 mg l-1 DOX). EC 682, other coliforms and anaerobic bacteria were enumerated daily. A selection of isolated DOX-resistant coliforms (n = 454) was characterized by rep-PCR clustering, PCR assays (Inc1 and tet(A)) and micro broth dilution susceptibility tests (Sensititre). Both 1 and 4 mg l-1 DOX-enriched medium had a significantly higher selective effect on EC 682 and other resistant coliforms than medium without DOX. Transconjugants of EC 682 were isolated more frequently in the presence of 1 and 4 mg l-1 DOX compared to medium without DOX.CONCLUSIONS:
Subtherapeutic intestinal DOX concentrations have the potential to select for DOX-resistant E. coli, and promote the selection of transconjugants in a porcine caecum model. SIGNIFICANCE AND IMPACT OF THE STUDY Cross-contamination of feed with antimicrobials such as DOX likely promotes the spread of antimicrobial resistance. Therefore, it is important to develop or fine-tune guidelines for the safe use of antimicrobials in animal feed and its storage.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Plasmídeos
/
Ceco
/
Doxiciclina
/
Conjugação Genética
/
Escherichia coli
/
Ração Animal
/
Antibacterianos
Limite:
Animals
Idioma:
En
Revista:
J Appl Microbiol
Assunto da revista:
MICROBIOLOGIA
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Bélgica