College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China.
Int J Food Microbiol. 2011 Oct 3;149(3):274-7. doi: 10.1016/j.ijfoodmicro.2011.07.006. Epub 2011 Jul 13.
A total of 81 Salmonella isolates from retail meats and seafood in Hebei province, China, were assayed for the presence of and horizontal transfer of class 1 integrons. By the PCR screening for the integrons, class 1 integron was detected from strains in serotypes of Derby, Indiana, London and Choleraesuis, which were isolated from pork, chicken or seafood; however, two isolates contained the empty integron that lacked the resistance cassette, a potential hotspot for development of the multidrug resistance. In contrast, two other isolates had the antibiotic resistance gene cassettes within the class 1 integron, which were dfrA1-aadA1 and aadB-cmlA, respectively. The conjugation experiments demonstrated the plasmid-mediated transfer of the class 1 integrons. Furthermore, each of the integrons was transmitted to Streptococcus mutans via natural gene transformation. These findings suggest the possible transfer of class 1 integrons from foodborne pathogens to human residential bacteria via horizontal gene transfer.
本研究对河北省零售肉及海鲜中 81 株沙门氏菌进行了 1 类整合子的存在及其水平转移检测。通过对整合子的 PCR 筛选，从猪肉、鸡肉或海鲜中分离出的德比、印第安纳、伦敦和霍乱血清型菌株中检测到 1 类整合子，然而，有 2 株分离株含有缺乏耐药盒的空整合子，这是多药耐药性发展的潜在热点。相比之下，另外 2 株分离株的 1 类整合子内含有抗生素耐药基因盒，分别为 dfrA1-aadA1 和 aadB-cmlA。接合实验表明 1 类整合子可通过质粒介导转移。此外，每个整合子都通过自然基因转化传递到变形链球菌。这些发现表明，1 类整合子可能通过水平基因转移从食源性病原体转移到人类居住细菌。
