Copy Number Change of the NDM-1 sequence in a multidrug-resistant Klebsiella pneumoniae clinical isolate.
Copy Number Change of the NDM-1 sequence in a multidrug-resistant Klebsiella pneumoniae clinical isolate.
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DOI：
10.1371/journal.pone.0062774
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Tsai SF
中科院分区：
文献类型：
--
作者：
Huang TW;Chen TL;Chen YT;Lauderdale TL;Liao TL;Lee YT;Chen CP;Liu YM;Lin AC;Chang YH;Wu KM;Kirby R;Lai JF;Tan MC;Siu LK;Chang CM;Fung CP;Tsai SF
研究了携带 bla NDM-1 的多重耐药肺炎克雷伯菌菌株的抗菌药物耐药性的遗传特征，以加深我们对 NDM-1 进化的理解。该毒株KPX来自一名在新德里有住院史的台湾患者。进行了完整的 DNA 测序；通过文库筛选系统地检查和分离了负责抗菌素耐药性的基因。 KPX 含有两个抗性质粒 pKPX-1 和 pKPX-2，大小分别为 250 kb 和 141 kb，bla NDM-1 存在于 pKPX-1 上。质粒pKPX-1包含与IncR和IncF组相关的基因，而pKPX-2属于IncF家族。每个质粒都携带多种抗菌素耐药性遗传决定因素。在 pKPX-1 上发现了负责碳青霉烯类抗性的基因，在 pKPX-2 上发现了负责氨曲南抗性的基因。令我们惊讶的是，我们发现 bla NDM-1 以串联重复形式的多个拷贝存在于 pKPX-1 上。发现 bla NDM-1 的扩增是通过 8.6 kb 单位的重复而发生的，重复的拷贝数因菌落而异。除了两个碱基替换之外，该重复序列与 pNDM-MAR 的重复序列相同。通过Southern印迹和定量PCR评估不同条件下菌落的bla NDM-1拷贝数。 bla NDM-1 序列在抗菌选择存在的情况下得以维持；然而，消除抗菌选择导致易感细菌群体的出现，其拷贝数减少，甚至 bla NDM-1 序列完全丢失。 NDM-1 序列的动态性质为明智地使用广谱抗菌药物以减少病原体中抗菌药物耐药性的产生和传播提供了强有力的论据。
The genetic features of the antimicrobial resistance of a multidrug resistant Klebsiella pneumoniae strain harboring bla NDM-1 were investigated to increase our understanding of the evolution of NDM-1. The strain, KPX, came from a Taiwanese patient with a hospitalization history in New Delhi. Complete DNA sequencing was performed; and the genes responsible for antimicrobial resistance were systematically examined and isolated by library screening. KPX harbored two resistance plasmids, pKPX-1 and pKPX-2, which are 250-kb and 141-kb in size, respectively, with bla NDM-1 present on pKPX-1. The plasmid pKPX-1 contained genes associated with the IncR and IncF groups, while pKPX-2 belonged to the IncF family. Each plasmid carried multiple antimicrobial resistance genetic determinants. The gene responsible for resistance to carbapenems was found on pKPX-1 and that for resistance to aztreonam was found on pKPX-2. To our surprise, we discovered that bla NDM-1 exists on pKPX-1 as multiple copies in the form of tandem repeats. Amplification of bla NDM-1 was found to occur by duplication of an 8.6-kb unit, with the copy number of the repeat varying from colony to colony. This repeat sequence is identical to that of the pNDM-MAR except for two base substitutions. The copy number of bla NDM-1 of colonies under different conditions was assessed by Southern blotting and quantitative PCR. The bla NDM-1 sequence was maintained in the presence of the antimicrobial selection; however, removal of antimicrobial selection led to the emergence of susceptible bacterial populations with a reduced copy number or even the complete loss of the bla NDM-1 sequence. The dynamic nature of the NDM-1 sequence provides a strong argument for judicious use of the broad-spectrum antimicrobials in order to reduce the development and spread of antimicrobial resistance among pathogens.
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影响因子：
4.9
作者：
Mc Gann, Patrick;Hang, Jun;Waterman, Paige E.
通讯作者：
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影响因子：
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影响因子：
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作者：
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Nordmann P
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作者：
Bertini, Alessia;Poirel, Laurent;Carattoli, Alessandra
通讯作者：
Carattoli, Alessandra