由台灣健康豬隻分離之大腸桿菌對氟甲磺氯黴素與氯黴素抗藥性及其相關基因之研究   全文下載

Molecular Detection of Florfenicol and Chloramphenicol Resistance among Escherichia coli Isolates from Healthy Pigs During 2003 to 2007

於2003 年至2007 年間由50 個不同豬場共收集600 個健康豬隻糞便樣本，調查由豬隻分離之大腸桿菌對於動物用氟甲磺氯黴素與人醫所使用氯黴素抗藥性及其相關基因之研究。結果顯示豬源大腸桿菌對於氟甲磺氯黴素抗藥性比例由2003 年的39.2% 上升至2007 年的78.3%。本次試驗分別由保育豬（61.5%）、肥育豬（62.5%）與母豬（51.5%）分離出351 株抗藥性菌株，分析抗藥性菌株帶有藥物輸出幫浦基因floR、cmlA 與氯黴素乙醯轉移?基因cat-1, cat-2 與cat-3 比例分別為82.9、61.3、10.8、3.7 與0%，而同時帶有floR 及cmlA 基因菌株的比例為52.4%。抗藥性菌株在同時存有藥物輸出幫浦抑制劑Phe-Arg-β-naphthylamide 時，氟甲磺氯黴素對於大腸桿菌最小抑制濃度則下降4 至64 倍。本研究結果顯示：台灣豬隻大腸桿菌分離株，大部分均藉由藥物輸出幫浦對於氟甲磺氯黴素與氯黴素產生抗藥性。未來將進一步研究上述抗藥性基因在人畜間的差異及其交互傳播可能的途徑。"

In order to elucidate the possible genetic determinants of resistance to florfenicol and chloramphenicol in porcine Escherichia coli in Taiwan, 600 fecal samples of healthy pigs from 50 different farms were collected from 2003 to 2007. The florfenicol resistance in the isolated E. coli strains doubled from 39.2% in 2003 to 78.3% in 2007. A total of 351 florfenicol-resistant E. coli isolates were isolated from nursery pigs (61.5%), grower-finisher pigs (62.5%), and sows (51.5%). The prevalence of resistance genes, floR, cmlA, cat-1, cat-2 and cat-3, was 82.9, 61.3, 10.8, 3.7, and 0%, respectively. Of the 351 florfenicol-resistant isolates, 184 (52.4%) were positive for both floR and cmlA. Furthermore, the results of efflux inhibitor studies with Phe-Arg-β-naphthylamide showed a 4- to 64-fold decrease in the florfenicol MIC levels. The FloR efflux pump may play a role in phenicol resistance among porcine E. coli isolates in Taiwan. More detailed studies are required to focus on the public health concerns about the spread of antimicrobial resistance from animal food products to humans through the food chain.