Institute of Veterinary Research of Tunisia, Tunis, Tunisia.
Foodborne Pathog Dis. 2009 Nov;6(9):1067-73. doi: 10.1089/fpd.2009.0284.
Fifty-five Escherichia coli isolates were acquired from chicken and turkey meat obtained from two slaughterhouses in Tunis. Eighty-nine percent, 80%, 78%, 67%, 45%, 27%, 7%, 4%, and 2% of these isolates showed resistance to tetracycline, trimethoprim/sulfamethoxazole, streptomycin, nalidixic acid, ampicillin, chloramphenicol, ciprofloxacin, colistine, and gentamicin, respectively. No resistance was detected to cefotaxime, ceftazidime, or amikacin. bla(TEM) gene was found in 22 of 25 ampicillin-resistant isolates, and 1 isolate harbored bla(OXA-1) gene. Tetracycline resistance was predominately mediated by the tetA gene. The sul1, sul2, and sul3 genes, alone or combined, were detected in 46 of 48 sulfonamide-resistant isolates, and sul1 and sul3 were included in class 1 integrons in some cases. Sixty percent of isolates harbored integrons (class 1, 30 isolates; class 2, 5 isolates). Class 2 integrons contained in all cases the dfrA1-sat1-aadA1-orfX gene cassette arrangement. Nine gene cassette arrangements have been detected among class 1 integrons, containing different alleles of dfrA (five alleles) and aadA (2 alleles) genes, which encode trimethoprim and streptomycin resistance, respectively. An uncommon gene cassette array (sat-psp-aadA2-cmlA1-aadA1-qacH-IS440-sul3) has been identified in three class 1 integron-positive isolates, and one additional isolate had this same structure with the insertion of IS26 inside the aadA1 gene (included in GenBank with accession no. FJ160769). The 55 studied isolates belong to the four phylogenic groups of E. coli, and phylogroups A and D were the most prevalent ones. At least one virulence-associated gene (fimA, papC, or aer) was detected in 44 of the 55 (80%) studied isolates. E. coli isolates of poultry origin could be a reservoir of antimicrobial-resistance genes and of integrons, and its evolution should be tracked in the future.
从突尼斯的两个屠宰场获得的鸡肉和火鸡肉中采集了 55 株大肠杆菌分离株。这些分离株中，89%、80%、78%、67%、45%、27%、7%、4%和 2%分别对四环素、甲氧苄啶/磺胺甲恶唑、链霉素、萘啶酸、氨苄西林、氯霉素、环丙沙星、黏菌素和庆大霉素表现出耐药性。未检测到对头孢噻肟、头孢他啶或阿米卡星的耐药性。在 25 株氨苄西林耐药分离株中发现了 bla(TEM)基因，1 株分离株携带 bla(OXA-1)基因。四环素耐药主要由 tetA 基因介导。在 48 株磺胺耐药分离株中，单独或联合检测到 sul1、sul2 和 sul3 基因，在某些情况下，sul1 和 sul3 被包含在 1 类整合子中。60%的分离株携带整合子（1 类，30 株；2 类，5 株）。2 类整合子中均包含 dfrA1-sat1-aadA1-orfX 基因盒排列。在 1 类整合子中检测到 9 种基因盒排列，包含不同的 dfrA（5 个等位基因）和 aadA（2 个等位基因）基因，分别编码对甲氧苄啶和链霉素的耐药性。在 3 株 1 类整合子阳性分离株中发现了一种不常见的基因盒排列（sat-psp-aadA2-cmlA1-aadA1-qacH-IS440-sul3），另外 1 株分离株在 aadA1 基因内插入了 IS26（包含在 GenBank 中，登录号为 FJ160769）。研究的 55 株分离株属于大肠杆菌的四个进化群，A 群和 D 群最为常见。在研究的 55 株（80%）中，至少检测到 1 种与毒力相关的基因（fimA、papC 或 aer）。禽类来源的大肠杆菌分离株可能是抗药性基因和整合子的储库，未来应跟踪其进化情况。
