Prevalence of extended-spectrum beta-lactamase-producing Escherichia coli
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- 作者：Daniela Costa ; Laura Vinué ; Patricia Poeta ; Ana Clá ; udia Coelho ; Manuela Matos ; Yol ; a Sá ; enz ; Sergio Somalo ; Myriam Zarazaga ; Jorge Rodrigues ; Carmen Torres
- 关键词：TEM-52 ; CTX-M-14 ; CTX-M-32 ; Broilers
- 刊名：Veterinary Microbiology
- 出版年：2009
- 出版时间：18 September 2009
- 年：2009
- 卷：138
- 期：3-4
- 页码：339-344
- 全文大小：177 K
文摘
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 blaTEM-52 gene and two of them also harboured blaTEM-1b. The blaCTX-M-14 gene was identified in three isolates (in association with blaTEM-1b in one of them), and blaCTX-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.