Mobilizable IncQ-related plasmid carrying a new quinolone resistance gene, qnrS2, isolated from the bacterial community of a wastewater treatment plant
Mobilizable IncQ-related plasmid carrying a new quinolone resistance gene, qnrS2, isolated from the bacterial community of a wastewater treatment plant
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DOI：
10.1128/aac.00378-06
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发表时间：
2006-09-01
影响因子：
4.9
通讯作者：
Schlueter, Andreas
中科院分区：
文献类型：
--
作者：
Boenemann, Gabriele;Stiens, Michael;Schlueter, Andreas
质粒编码的喹诺酮类药物耐药性以前不仅在美国和亚洲，而且在欧洲也报道过从患者身上分离的不同细菌。在这里，我们描述了通过应用一种新的选择策略，从德国一家污水处理厂的活性污泥细菌群落中分离出喹诺酮类药物抗性质粒pGNB2。将携带多药物外排系统基因acrAB突变的超敏大肠杆菌KAM3菌株用从活性污泥菌中分离的总质粒DNA制剂转化，然后在含氟喹诺酮诺氟沙星的培养基上选择。这种方法导致pGNB2质粒的分离，降低了对萘啶酸和不同氟喹诺酮类药物的敏感性。pGNB2核苷酸序列分析显示其大小为8,469 bp， G+C含量为58.2%。质粒主干由一个属于incq家族的复制起始模块（repA-repC）和一个赋予质粒水平迁移能力的双组分动员模块组成。此外，质粒pGNB2携带一个由转座子Tn1721残基和喹诺酮类耐药基因qnrS2组成的附属模块，该模块与来自福氏志贺氏杆菌2b的质粒pAH0376上的qnrS基因相同92%。QnrS2属于五肽重复蛋白家族，预计可保护dna旋切酶活性免受喹诺酮类药物的影响。这不仅是首次报道从环境样本中分离出喹诺酮类药物耐药的完全测序质粒，而且是在欧洲发现的第一个qnrs样基因。
Plasmid-encoded quinolone resistance was previously reported for different bacteria isolated from patients not only in the United States and Asia but also in Europe. Here we describe the isolation, by applying a new selection strategy, of the quinolone resistance plasmid pGNB2 from an activated sludge bacterial community of a wastewater treatment plant in Germany. The hypersensitive Escherichia coli strain KAM3 carrying a mutation in the multidrug efflux system genes acrAB was transformed with total plasmid DNA preparations isolated from activated sludge bacteria and subsequently selected on medium containing the fluoroquinolone norfloxacin. This approach resulted in the isolation of plasmid pGNB2 conferring decreased susceptibility to nalidixic acid and to different fluoroquinolones. Analysis of the pGNB2 nucleotide sequence revealed that it is 8,469 bp in size and has a G+C content of 58.2%. The plasmid backbone is composed of a replication initiation module (repA-repC) belonging to the IncQ-family and a two-component mobilization module that confers horizontal mobility to the plasmid. In addition, plasmid pGNB2 carries an accessory module consisting of a transposon Tn1721 remnant and the quinolone resistance gene, qnrS2, that is 92% identical to the qnrS gene located on plasmid pAH0376 from Shigella flexneri 2b. QnrS2 belongs to the pentapeptide repeat protein family and is predicted to protect DNA-gyrase activity against quinolones. This is not only the first report on a completely sequenced plasmid mediating quinolone resistance isolated from an environmental sample but also on the first qnrS-like gene detected in Europe.