Abstract：
Objective: The objective of this study was to characterize ICEAplChn2, a novel SXT/R391-related integration and conjugation element (ICE) carrying 19 drug resistance genes, in a clinical isolate of Actinobacillus pleuropneumoniae from swine. Methods: Whole genome sequencing (WGS) of A. pleuropneumoniae CP063424 strain was completed using a combination of third-generation PacBio and second-generation Illumina. The putative ICE was predicted by the online tool ICEfinder. ICEAplChn2 was analyzed by PCR, conjugation experiments, and bioinformatics tools. Results: A. pleuropneumoniae CP063424 strain exhibited high minimum inhibitory concentrations of clindamycin (1,024 mg/L). The WGS data revealed that ICEAplChn2, with a length of 167,870 bp and encoding 151 genes, including multiple antibiotic resistance genes such as erm(42), VanE, LpxC, dfrA1, golS, aadA3, EreA, dfrA32, tetR(C), tet(C), sul2, aph(3)″-lb, aph(6)-l, floR, dfrA, ANT(3″)-IIa, catB11, and VanRE, was found to be related to the SXT/R391 family on the chromosome of A. pleuronipneumoniae CP063424. The circular intermediate of ICEAplChn2 was detected by PCR, but conjugation experiments showed that it was not self-transmissible. Conclusions: To our knowledge, ICEAplChn2 is the longest member with the most resistance genes in the SXT/R391 family. Meanwhile, ATP-binding cassette superfamily was found to be inserted in the ICEAplChn2 and possessed a new insertion region, which is the first description in the SXT/R391 family.
摘要：
目的：本研究的目的是表征ICEAplChn2，一种携带19种耐药基因的新型SXT/R391相关整合和缀合元件（ICE），在猪胸膜肺炎放线杆菌的临床分离中。方法：使用第三代PacBio和第二代Illumina的组合完成胸膜肺炎杆菌CP063424菌株的全基因组测序（WGS）。推定的ICE由在线工具ICEfinder预测。ICEAplChn2通过PCR分析，共轭实验，和生物信息学工具。结果:胸膜肺炎杆菌CP063424菌株对克林霉素的最低抑菌浓度(1,024mg/L)较高。WGS数据显示，ICEAplChn2长度为167,870bp，编码151个基因，包括多个抗生素抗性基因，如erm(42)，Vane,LpxC,dfrA1,gls,aadA3,EreA,dfrA32,tetR(C),tet(C),sul2,aph(3)″-lb,aph(6)-l,floR,dfra,ANT(3″)-IIa,catB11和VanRE,发现与胸膜肺炎杆菌CP063424染色体上的SXT/R391家族相关。通过PCR检测ICEAplChn2的环状中间体，但是共轭实验表明它不是自我传播的。结论：据我们所知，ICEAplChn2是SXT/R391家族中具有最年夜抗性基因的最长成员。同时,发现ATP结合盒超家族被插入到ICEAplChn2中并具有新的插入区,这是SXT/R391系列中的第一个描述。
