Prevalence of extended-spectrum beta-lactamase-producing Escherichia coli isoaltes in faecal samples of broilers
- Costa, D. 15
- Vinué, L. 1
- Poeta, P. 25
- Coelho, A.C. 5
- Matos, M. 4
- Sáenz, Y. 13
- Somalo, S. 1
- Zarazaga, M. 13
- Rodrigues, J. 25
- Torres, C. 13
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1
Universidad de La Rioja
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- 2 Centre of Studies of Animal and Veterinary Sciences, Vila Real, Portugal
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3
Centro de Investigación Biomédica de La Rioja
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- 4 Departamento de Genética e Biotecnología, Instituto de Biotecnología e Bioengenharia, Vila Real, Portugal
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5
Universidade de Trás-os-Montes e Alto Douro
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ISSN: 0378-1135
Año de publicación: 2009
Volumen: 138
Número: 3
Páginas: 339-344
Tipo: Artículo
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Resumen
Seventy-six faecal samples were obtained from broilers at slaughterhouse level in Portugal. Samples were inoculated on cefotaxime-supplemented Levine agar plates. Cefotaxime-resistant Escherichia coli isolates were recovered from 32 samples (42.1%), obtaining a total of 34 E. coli isolates (one or two isolates per sample). Susceptibility to 16 antibiotics was studied by disk diffusion method, and 85% of the isolates presented a phenotype of multi-resistance that included antimicrobial agents of at least four different families. Extended-spectrum-beta-lactamases (ESBL) of the TEM and CTX-M groups were detected in 31 ESBL-positive E. coli isolates. Twenty-six isolates harboured the bla TEM-52 gene and two of them also harboured bla TEM-1b. The bla CTX-M-14 gene was identified in three isolates (in association with bla TEM-1b in one of them), and bla CTX-M-32 was demonstrated in two additional isolates. Three of the 34 cefotaxime-resistant isolates (9%) did not produce ESBLs, and two of them presented mutations at positions -42 (C → T), -18 (G → A), -1 (C → T), and +58(C → T) of the promoter/attenuator region of ampC gene. tet(A) and/or tet(B) genes were detected in all 34 tetracycline-resistant isolates, aadA in all 26 streptomycin-resistant isolates; cmlA in 3 of 6 chloramphenicol-resistant isolates, and aac(3)-II or aac(3)-I + aac(3)-IV genes in all 4 gentamicin-resistant isolates. Different combinations of sul1, sul2 and sul3 genes were demonstrated among the 22 trimethoprim-sulfamethoxazole-resistant isolates. Amino acid changes in GyrA and ParC proteins were identified in all 18 ciprofloxacin-resistant isolates. The results of this study indicate that the intestinal tract of healthy poultry is a reservoir of ESBL-positive E. coli isolates. © 2009 Elsevier B.V. All rights reserved.