Guang-Guo Ying
Ran Tao
Rui-Quan Zhang
Lisa R. Fogarty
Dana W. Kolpin
Hao-Chang Su
2011
<div class="capsule__text"><p>Antibiotics<span> </span>are still widely applied in animal husbandry to prevent diseases and used as feed additives to promote animal growth. This could result in<span> </span>antibiotic<span> </span>resistance to bacteria and<span> </span>antibiotic<span> </span>residues in animals. In this paper, Enterobacteriaceae isolated from four integrated fish farms in Zhongshan, South China were tested for<span> </span>antibiotic<span> </span>resistance,<span> </span>tetracycline<span> </span>resistance genes,<span> </span>sulfonamide<span> </span>resistance genes, and class 1 integrons. The Kirby-Bauer disk diffusion method and polymerase<span> </span>chain reaction<span> </span>(PCR) assays were carried out to test<span> </span>antibiotic<span> </span>susceptibility and resistance genes, respectively. Relatively high<span> </span>antibiotic<span> </span>resistance frequencies were found, especially for ampicillin (80%),<span> </span>tetracycline<span> </span>(52%), and<span> </span>trimethoprim<span> </span>(50%). Out of 203 Enterobacteriaceae isolates, 98.5% were resistant to one or more<span> </span>antibiotics<span> </span>tested. Multiple<span> </span>antibiotic<span> </span>resistance (MAR) was found highest in animal manures with a MAR index of 0.56.<span> </span>Tetracycline<span> </span>resistance genes (<i>tet</i>(A),<span> </span><i>tet</i>(C)) and<span> </span>sulfonamide<span> </span>resistance genes (<i>sul2</i>) were detected in more than 50% of the isolates. The<span> </span><i>intI1</i>gene was found in 170 isolates (83.7%). Both classic and non-classic class 1 integrons were found. Four genes,<span> </span><i>aadA5</i>,<span> </span><i>aadA22</i>,<span> </span><i>dfr2</i>, and<span> </span><i>dfrA17</i>, were detected. To our knowledge, this is the first report for molecular characterization of<span> </span>antibiotic<span> </span>resistance genes in Enterobacteriaceae isolated from integrated fish farms in China and the first time that gene cassette array<i>dfrA17-aadA5</i><span> </span>has been detected in such fish farms. Results of this study indicated that fish farms may be a reservoir of highly diverse and abundant<span> </span>antibiotic<span> </span>resistant genes and gene cassettes. Integrons may play a key role in multiple<span> </span>antibiotic<span> </span>resistances posing potential health risks to the general public and aquaculture.</p></div>
application/pdf
10.1039/C1EM10634A
en
Royal Society of Chemistry Publishing
Occurrence of antibiotic resistance and characterization of resistant genes and integrons in Enterobacteriaceae isolated from integrated fish farms south China
article