Identification of Tn5397-like and Tn916-like transposons and diversity of the tetracycline resistance gene tet(M) in enterococci from humans, pigs and poultry
Identification of Tn5397-like and Tn916-like transposons and diversity of the tetracycline resistance gene tet(M) in enterococci from humans, pigs and poultry
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DOI：
10.1093/jac/dkl069
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发表时间：
2006-05-01
影响因子：
5.2
通讯作者：
Aarestrup, FM
中科院分区：
文献类型：
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作者：
Agerso, Y;Pedersen, AG;Aarestrup, FM
目的：目的：分析丹麦人、猪和家禽来源的屎肠球菌和粪肠球菌四环素耐药基因泰特（M）的序列多样性及其在移动的元件上的定位。对其中15个分离株的泰特（M）进行测序，并与GenBank中提交的泰特（M）序列进行比较（系统发育分析和重组迹象）。结果：13株大肠杆菌中，有8株为Tn 5397类转座子。泰特（M）主要存在于Tn 5397类转座子上，而泰特（M）在大肠杆菌中主要存在于Tn 916/Tn 1545类转座子上。猪和人的屎肠球菌，以及E.来自人、猪和肉鸡的粪便菌（63个分离株中的50个）。根据系统发育分析，泰特（M）基因可分为3个主要亚群。亚组I包括艰难梭菌的泰特（M）和E.第二亚群由位于Tn 916/Tn 1545家族转座子上的泰特（M）组成，第三亚群由与含有多个抗性基因的复合元件相关的泰特（M）组成。我们发现了这些群体内部和群体之间重组的证据。此外，我们还鉴定了一个E.结论：本研究表明肠球菌中泰特（M）基因存在于不同的移动的元件上，这可能提示肠球菌在携带泰特（M）的移动的元件的进化和水平传播中起重要作用。这是第一次在肠球菌中发现Tn 5397样元件。
Objectives: To analyse the sequence diversity of the tetracycline resistance gene tet(M) and its location on mobile elements in Enterococcus faecium and Enterococcus faecalis from humans, pigs and poultry in Denmark.Methods: A total of 76 isolates were screened for Tn916/Tn1545-like and Tn5397-like transposons using PCR. tet(M) was sequenced in 15 of the isolates and compared with tet(M) sequences submitted to GenBank (phylogenetic analysis and signs of recombination). Plasmids were extracted, filter-mating experiments were performed and Tn5397-like transposons were further characterized in selected isolates.Results: In 8 of 13 isolates of E. faecium from broilers, tet(M) was present on Tn5397-like transposons, whereas tet(M) was predominantly associated with Tn916/Tn1545-like transposons in E. faecium from pigs and humans, as well as in E. faecalis from humans, pigs and broilers (50 of 63 isolates). The tet(M) genes were divided into three major subgroups according to the phylogenetic analysis. Subgroup I consisted of tet(M) from Clostridium difficile and E. faecium associated with Tn5397-like elements, subgroup II consisted of tet(M) located on Tn916/Tn1545 family transposons and subgroup III consisted of tet(M) associated with composite elements containing several resistance genes. We found evidence of recombination both within and between these groups. Moreover, we identified an E. faecium isolate with both Tn916/Tn1545-like and Tn5397-like elements.Conclusions: This study showed that enterococci contain diverse tet(M) genes present on different mobile elements, which may suggest that enterococci play an important role in the evolution and horizontal spread of mobile elements carrying tet(M). This is the first report of Tn5397-like elements in enterococci.