ICEPmu1, an integrative conjugative element (ICE) of Pasteurella multocida: analysis of the regions that comprise 12 antimicrobial resistance genes
ICEPmu1, an integrative conjugative element (ICE) of Pasteurella multocida: analysis of the regions that comprise 12 antimicrobial resistance genes
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DOI：
10.1093/jac/dkr406
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发表时间：
2012-01-01
影响因子：
5.2
通讯作者：
Schwarz, Stefan
中科院分区：
文献类型：
--
作者：
Michael, Geovana Brenner;Kadlec, Kristina;Schwarz, Stefan
背景：近年来，从牛呼吸道感染中鉴定出多杀性巴氏杆菌多重耐药株。这些菌株表现出耐药性的大多数类别的抗生素常用的兽药，其中，然而，在很大程度上是未知的遗传基础。方法：基因组DNA的一个代表性的多杀性巴氏杆菌分离进行全基因组测序。基因已预测的YACOP程序，与SWISSProt/EMBL数据库和人工策划使用注释软件ERGO。结果：1株代表性的多杀性巴氏杆菌染色体DNA中整合了一个82 kb的整合接合元件（integrative and conjugative element，ICE）。该ICE命名为ICEPmu 1，携带11种耐药基因，可对链霉素/大观霉素（aadA 25）、链霉素（strA和strB）、庆大霉素（aadB）、卡那霉素/新霉素（aphA 1）、四环素[tetR-tet（H）]、氯霉素/氟苯尼考（floR）、磺胺类药物（sul 2）、替米考星/克林霉素[flv（42）]或替米考星/妥拉霉素[msr（E）-mph（E）]产生耐药性。此外，检测到一个完整的bla（OXA-2）基因，但似乎在多杀性巴氏杆菌中功能失活。这些抗性基因被组织在两个区域，约15.7和9.8 kb。根据获得的序列，很可能质粒、基因盒和插入序列在ICE中两个抗性基因区域的发展中发挥了作用。观察到12个耐药基因，组织在两个耐药基因区域，代表多杀性巴氏杆菌ICE的一部分，强调了通过单一水平基因转移事件同时获得多个耐药基因的风险。
Background: In recent years, multiresistant Pasteurella multocida isolates from bovine respiratory tract infections have been identified. These isolates have exhibited resistance to most classes of antimicrobial agents commonly used in veterinary medicine, the genetic basis of which, however, is largely unknown.Methods: Genomic DNA of a representative P. multocida isolate was subjected to whole genome sequencing. Genes have been predicted by the YACOP program, compared with the SWISSProt/EMBL databases and manually curated using the annotation software ERGO. Susceptibility testingwas performed by broth microdilution according to CLSI recommendations.Results: The analysis of one representative P. multocida isolate identified an 82 kb integrative and conjugative element (ICE) integrated into the chromosomal DNA. This ICE, designated ICEPmu1, harboured 11 resistance genes, which confer resistance to streptomycin/spectinomycin (aadA25), streptomycin (strA and strB), gentamicin (aadB), kanamycin/neomycin (aphA1), tetracycline [tetR-tet(H)], chloramphenicol/florfenicol (floR), sulphonamides (sul2), tilmicosin/clindamycin [erm(42)] or tilmicosin/tulathromycin [msr(E)-mph(E)]. In addition, a complete bla(OXA-2) gene was detected, which, however, appeared to be functionally inactive in P. multocida. These resistance genes were organized in two regions of approximately 15.7 and 9.8 kb. Based on the sequences obtained, it is likely that plasmids, gene cassettes and insertion sequences have played a role in the development of the two resistance gene regions within this ICE.Conclusions: The observation that 12 resistance genes, organized in two resistance gene regions, represent part of an ICE in P. multocida underlines the risk of simultaneous acquisition of multiple resistance genes via a single horizontal gene transfer event.