Unité Antibiorésistance et Virulence Bactériennes, Anses Lyon, 31 Avenue Tony Garnier, F-69364 Lyon Cedex 07, France.
Appl Environ Microbiol. 2010 Dec;76(24):7957-65. doi: 10.1128/AEM.00805-10. Epub 2010 Oct 15.
Bovine isolates of Streptococcus agalactiae (n = 76), Streptococcus dysgalactiae subsp. dysgalactiae (n = 32), and Streptococcus uberis (n = 101) were analyzed for the presence of different integrative and conjugative elements (ICEs) and their association with macrolide, lincosamide, and tetracycline resistance. The diversity of the isolates included in this study was demonstrated by multilocus sequence typing for S. agalactiae and pulsed-field gel electrophoresis for S. dysgalactiae and S. uberis. Most of the erythromycin-resistant strains carry an ermB gene. Five strains of S. uberis that are resistant to lincomycin but susceptible to erythromycin carry the lin(B) gene, and one has both linB and lnuD genes. In contrast to S. uberis, most of the S. agalactiae and S. dysgalactiae tetracycline-resistant isolates carry a tet(M) gene. A tet(S) gene was also detected in the three species. A Tn916-related element was detected in 30 to 50% of the tetracycline-resistant strains in the three species. Tetracycline resistance was successfully transferred by conjugation to an S. agalactiae strain. Most of the isolates carry an ICE integrated in the rplL gene. In addition, half of the S. agalactiae isolates have an ICE integrated in a tRNA lysine (tRNA(Lys)) gene. Such an element is also present in 20% of the isolates of S. dysgalactiae and S. uberis. A circular form of these ICEs was detected in all of the isolates tested, indicating that these genetic elements are mobile. These ICEs could thus also be a vehicle for horizontal gene transfer between streptococci of animal and/or human origin.
对 76 株无乳链球菌、32 株兽疫链球菌和 101 株停乳链球菌分离株进行了分析，以确定其是否存在不同的整合子和转座子（ICEs），及其与大环内酯类、林可酰胺类和四环素类耐药性的关系。本研究中包括的分离株的多样性通过无乳链球菌的多位点序列分型和兽疫链球菌和停乳链球菌的脉冲场凝胶电泳来证明。大多数红霉素耐药株携带 ermB 基因。5 株对林可霉素耐药但对红霉素敏感的停乳链球菌携带 lin(B)基因，1 株同时携带 linB 和 lnuD 基因。与停乳链球菌不同的是，大多数四环素耐药的无乳链球菌和兽疫链球菌携带 tet(M)基因。在这三个物种中也检测到了 tet(S)基因。在三个物种的 30%到 50%的四环素耐药株中检测到了与 Tn916 相关的元件。四环素耐药性通过接合成功地转移到一株无乳链球菌株中。大多数分离株携带整合在 rplL 基因中的 ICE。此外，一半的无乳链球菌分离株携带整合在 tRNA 赖氨酸（tRNA(Lys))基因中的 ICE。这种元件也存在于 20%的兽疫链球菌和停乳链球菌分离株中。在所有测试的分离株中都检测到了这些 ICE 的环状形式，表明这些遗传元件是可移动的。因此，这些 ICE 也可能是动物和/或人类来源的链球菌之间水平基因转移的载体。
