Broad Dissemination of Plasmid-Mediated Quinolone Resistance Genes in Sediments of Two Urban Coastal Wetlands
Broad Dissemination of Plasmid-Mediated Quinolone Resistance Genes in Sediments of Two Urban Coastal Wetlands
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DOI：
10.1021/es1029206
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发表时间：
2011-01-15
影响因子：
11.4
通讯作者：
Zuill, Douglas E.
中科院分区：
文献类型：
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作者：
Cummings, David E.;Archer, Karisa F.;Zuill, Douglas E.
土壤和水被抗生素抗性细菌污染可能会产生抗生素抗性基因库，这些基因有可能通过水平基因转移对未来的公共健康产生负面影响。质粒介导的喹诺酮抗性基因 qnrA、qnrB、qnrS、qepA 和 aac(6')-lb-cr 通过 PCR 扩增提华纳河口（美国-墨西哥边境受污水影响的沿海湿地）表面沉积物的宏基因组 DNA 检测到； Famosa Slough 是附近的一个城市湿地，基本上不受污水影响，其沉积物仅含有 qnrB、qnrS 和 qepA。降雨后，两个湿地中 PCR 阳性位点和重复的数量均有所增加。实时定量 PCR 显示，降雨后蒂华纳河口沉积物中的 qnrA 丰度（每克沉积物的拷贝数或每 16S rDNA 拷贝数）显着增加 (p < 0.0005)，但在 Famosa Slough 没有测量到显着变化 (p > 0.1)。克隆的 qnrA 扩增子的核苷酸序列均与临床分离株质粒上发现的 qnrA 基因相关，但有一个例外，它与希瓦氏藻中发现的染色体 qnrA 基因最相似。我们的研究结果表明，城市湿地可能成为抗生素抗性基因的储存库，特别是在废水管理不当的地方。
Contamination of soil and water with antibiotic-resistant bacteria may create reservoirs of antibiotic resistance genes that have the potential to negatively impact future public health through horizontal gene transfer. The plasmid-mediated quinolone resistance genes qnrA, qnrB, qnrS, qepA, and aac(6')-lb-cr were detected by PCR amplification of metagenomic DNA from surface sediments of the Tijuana River Estuary, a sewage-impacted coastal wetland along the U.S.-Mexico border; sediments of Famosa Slough, a nearby urban wetland that is largely unaffected by sewage, contained only qnrB, qnrS, and qepA. The number of PCR-positive sites and replicates increased in both wetlands after rainfall. Real-time quantitative PCR revealed a significant increase (p < 0.0005) in qnrA abundance (copies per gram sediment or per 16S rDNA copy) in Tijuana River Estuary sediments immediately following rainfall, but no significant change was measured at Famosa Slough (p > 0.1). Nucleotide sequences of cloned qnrA amplicons were all affiliated with qnrA genes found on plasmids of clinical isolates with one exception that was most similar to the chromosomal qnrA gene found in Shewanella algae. Our results suggest that urban wetlands may become reservoirs of antibiotic resistance genes, particularly where wastewater is improperly managed.