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首页> 外文期刊>Environmental Science & Technology >Tetracycline Resistance Gene Maintenance under Varying Bacterial Growth Rate, Substrate and Oxygen Availability, and Tetracycline Concentration
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Tetracycline Resistance Gene Maintenance under Varying Bacterial Growth Rate, Substrate and Oxygen Availability, and Tetracycline Concentration

机译：在细菌生长速率，底物和氧气利用率以及四环素浓度变化的情况下四环素抗性基因维持

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摘要

Neither amplification nor attenuation of antibiotic resistance genes (ARG) in the environment are well understood processes. Here, we report on continuous culture and batch experiments to determine how tetracycline (TC), aerobic vs anaerobic conditions, bacterial growth rate, and medium richness affect the maintenance of plasmid-borne TC resistance (Tet~R) genes. The response of E. coli (a model resistant strain excreted by farm animals) versus Pseudomonas aeruginosa (a model bacterium that could serve as a reservoir for ARGs in the environment) were compared to gain insight into response variability. Complete loss of the Tet~R RP1 plasmid (56 kb) occurred for P. aeruginosa in the absence of TC, and faster loss was observed in continuous culture at higher growth rates. In contrast, E. coli retained its smaller pSC101 plasmid (9.3 fcb) after 500 generations without TC (albeit at lower levels, with ratios of resistance to 16S rDNA genes decreasing by about 2-fold). A higher rate of ARG loss was observed in P. aeruginosa when grown in minimal growth medium (M9) than in richer Luria broth. Faster ARG loss occurred in E, coli under anaerobic (fermentative) conditions than under aerobic conditions. Thus, in these two model strains it was observed that conditions that ease the metabolic burden of plasmid reproduction (e.g., higher substrate and O_2 availability) enhanced resistance plasmid maintenance; such conditions (in the presence of residual antibiotics) may be conducive to the establishment and preservation of ARG reservoirs in the environment. These results underscore the need to consider antibiotic concentrations, redox conditions, and substrate availability in efforts to evaluate ARG propagation and natural attenuation.
机译：众所周知，环境中的抗生素抗性基因（ARG）的扩增或减弱都没有。在这里，我们报告连续培养和分批实验，以确定四环素（TC），有氧与厌氧条件，细菌生长速率和培养基富集如何影响质粒传播的TC抗性（Tet〜R）基因的维持。比较了大肠杆菌（一种被农场动物排泄的抗药性菌株）与铜绿假单胞菌（一种可作为环境中ARGs的宿主的模型细菌）的反应，以深入了解反应的变异性。在没有TC的情况下，铜绿假单胞菌发生了Tet〜R RP1质粒的完全缺失（56 kb），并且在连续培养中以较高的生长速率观察到了更快的缺失。相反，大肠杆菌在没有TC的500代后仍保留了其较小的pSC101质粒（9.3 fcb）（尽管处于较低水平，对16S rDNA基因的抗性比降低了约2倍）。当在基本生长培养基（M9）中生长时，铜绿假单胞菌比在较丰富的Luria肉汤中观察到的ARG丢失率更高。在大肠杆菌中，厌氧（发酵）条件下的ARG损失要比有氧条件下更快。因此，在这两种模型菌株中，观察到减轻质粒繁殖的代谢负担的条件（例如，较高的底物和O 2利用率）增强了抗性质粒的维持。这样的条件（在残留抗生素的存在下）可能有利于在环境中建立和保存ARG储库。这些结果强调了在评估ARG繁殖和自然衰减的努力中需要考虑抗生素浓度，氧化还原条件和底物可用性。

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  • 来源
    《Environmental Science & Technology》 |2013年第13期|6995-7001|共7页
  • 作者

    Michal Rysz; William R. Mansfield; John D. Fortner; Pedro J. J. Alvarez;

  • 作者单位

    GSI Environmental Inc., 2211 Norfolk, Suite 1000, Houston, Texas 77098, United States;

    Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States;

    Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States;

    Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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