Analysing diversity among β-lactamase encoding genes in aquatic environments
Analysing diversity among β-lactamase encoding genes in aquatic environments
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DOI：
10.1111/j.1574-6941.2006.00073.x
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发表时间：
2006-06-01
影响因子：
4.2
通讯作者：
Correia, Antonio
中科院分区：
文献类型：
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作者：
Henriques, Isabel;Moura, Alexandra;Correia, Antonio
对β-内酰胺类抗生素耐药的最常见机制是产生β-内酰胺酶。这些酶由快速进化的基因编码，因此构成了一个以高水平分子多样性为特征的群体。迄今为止，大多数β-内酰胺类抗生素耐药性的遗传决定因素均来自临床分离株。本研究的目的是利用β-内酰胺酶基因序列在水生环境中的存在，并获得这些序列的显着特点的信息时，与其他数据库中可用。评估了可能编码三种不同临床相关β-内酰胺酶家族蛋白质的DNA序列：TEM、IMP和OXA-2衍生物。通过PCR和杂交检查从泻湖Ria de阿韦罗的水样中提取的DNA中bla序列的存在。检测代表所研究的三个β-内酰胺酶家族的序列。扩增子的分子多样性通过克隆和序列分析以及变性梯度凝胶电泳（PCR-DGGE）分离来评估。大多数检索到的序列（特别是代表bla（TEM）和bla（OXA-2）的序列）与之前从临床分离株中表征的β-内酰胺酶基因序列相同或非常相似。系统发育分析表明，这一水生生态系统是一个水库的分子多样性推定的bla序列。所研究的β-内酰胺酶基因家族中发现的分子多样性模式与针对临床分离株的研究中报告的模式不一致。
The most common mechanism of resistance to beta-lactam antibiotics is the production of beta-lactamases. These enzymes are encoded by genes that evolve rapidly, thus constituting a group characterized by high levels of molecular diversity. Most of the genetic determinants of resistance to beta-lactam antibiotics characterized until now were obtained from clinical isolates. This study was designed in order to exploit the presence of beta-lactamase gene sequences in an aquatic environment, and to get information on the distinctive features of those sequences when compared to others available on databases. DNA sequences potentially encoding proteins of three different families of clinically relevant beta-lactamases were assessed: TEM, IMP and OXA-2 derivatives. The presence of bla sequences in DNA extracted from water samples from the lagoon Ria de Aveiro was checked by PCR and hybridization. Sequences representing the three families of beta-lactamases studied were detected. The molecular diversity of the amplicons was assessed by cloning and sequence analysis, and denaturing gradient gel electrophoresis (PCR-DGGE) separation. Most of the retrieved sequences (particularly sequences representing bla(TEM) and bla(OXA-2)) were identical or very similar to beta-lactamase gene sequences previously characterized from clinical isolates. Phylogenetic analysis suggests that this aquatic ecosystem is a reservoir of molecular diverse putative bla sequences. The patterns of molecular diversity found within the beta-lactamase gene families studied do not correspond to those reported in studies focussing on clinical isolates.