Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany; Chair of Geobiotechnology, Technische Universität Berlin, Berlin, Germany.
Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
Environ Int. 2019 May;126:118-126. doi: 10.1016/j.envint.2019.02.001. Epub 2019 Feb 20.
Increasing introduction of antibiotic residues from humans and animal farming into the environment impacts the functioning of natural ecosystems and significantly contributes to the propagation of antibiotic resistance. Microbial degradation is the major sink of antibiotics in soil but the identification of in situ degrading populations is challenging. Here, we investigated sulfamethoxazole-degrading bacteria in soil microcosms by culture-independent DNA and protein stable isotope probing. 0.5% of the carbon from C-labeled sulfamethoxazole amended to soil microcosms was transformed to CO demonstrating partial mineralization of the antibiotic. DNA stable isotope probing revealed incorporation of C from C-labeled sulfamethoxazole into Actinobacteria and among them into the families Intrasporangiaceae, Nocardioidaceae, and Gaiellaceae and the order Solirubrobacterales. Protein stable isotope probing demonstrated the incorporation of C from C-labeled sulfamethoxazole into proteins of bacteria of the families Intrasporangiaceae, Nocardioidaceae and the order Solirubrobacterales, which is consistent with the results of DNA stable isotope probing. The C abundance of 60 to 80% in several taxonomically relevant proteins indicated that Intrasporangiaceae directly acquired carbon from C-labeled sulfamethoxazole. The results highlight the crucial role of yet-uncultivated indigenous bacteria for antibiotics degradation, and the potential of cultivation-independent stable isotope based molecular approaches to elucidate the structure of antibiotic-degrading populations in complex microbial communities under natural conditions.
人类和动物养殖抗生素残留不断增多进入环境，影响自然生态系统的功能，并极大地促成了抗生素耐药性的传播。微生物降解是土壤中抗生素的主要归宿，但原位降解菌群的鉴定具有挑战性。在这里，我们通过非培养的 DNA 和蛋白质稳定同位素探测，研究了土壤微宇宙中的磺胺甲恶唑降解细菌。在土壤微宇宙中添加的 C 标记磺胺甲恶唑有 0.5%转化为 CO，表明抗生素部分矿化。DNA 稳定同位素探测显示，C 标记磺胺甲恶唑中的 C 掺入到放线菌中，其中包括孢囊菌科、诺卡氏菌科和 Gaillaceae 以及 Solirubrobacterales 目。蛋白质稳定同位素探测表明，C 标记磺胺甲恶唑中的 C 掺入到孢囊菌科、诺卡氏菌科和 Solirubrobacterales 目细菌的蛋白质中，这与 DNA 稳定同位素探测的结果一致。在几个分类学上相关的蛋白质中，C 的丰度为 60%到 80%，表明孢囊菌科直接从 C 标记的磺胺甲恶唑中获取碳。这些结果突出表明，尚未培养的土著细菌在抗生素降解中起着至关重要的作用，并且非培养的基于稳定同位素的分子方法具有阐明在自然条件下复杂微生物群落中抗生素降解种群结构的潜力。
