University of Gothenburg, Department of Biological and Environmental Sciences, Gothenburg, Sweden.
University of Gothenburg, Department of Biological and Environmental Sciences, Gothenburg, Sweden.
Aquat Toxicol. 2014 Nov;156:248-58. doi: 10.1016/j.aquatox.2014.08.015. Epub 2014 Sep 16.
Ciprofloxacin and sulfamethoxazole are two antibiotics commonly detected in the aquatic environment, but information on their toxicity towards natural microbial communities is largely absent. In particular no data are available for marine microorganisms. The aim of the current study was therefore to evaluate the chronic toxicity of ciprofloxacin and sulfamethoxazole to natural marine biofilms (periphyton), a complex ecological community comprising a variety of bacterial and algal species. The biofilms were sampled along the Swedish west coast and subsequently exposed over 4 days in a semi-static system to a concentration series of each antibiotic. Effects on the bacterial part of the periphyton community were assessed using Biolog Ecoplates, reflecting total respiration and functional diversity of the bacterial community. Exposure to either antibiotic resulted in a clear concentration-response relationship with EC10 and EC50 values for the inhibition of total carbon source utilization of 46.1nmol/L and 490.7nmol/L for ciprofloxacin, and 56nmol/L and 1073nmol/L for sulfamethoxazole. The NOEC for ciprofloxacin was 26nmol/L, with a minimum significant difference of 19.24%, for sulfamethoxazole it was 140nmol/L with a minimum significant difference of 14%. Multivariate data exploration of the whole carbon source utilization pattern confirmed these results. The data indicate that sulfamethoxazole leads to a general decrease in carbon source utilization, while ciprofloxacin exposure leads to a re-arrangement of the carbon-utilization pattern in the region of 20- 50% effect. This corresponds with the higher specificity of ciprofloxacin for certain bacterial species. Effects on the algal part of the communities were evaluated by analyzing the amount and composition of photosynthetic pigments, and neither ciprofloxacin nor sulfamethoxazole caused any inhibitory effects up to the maximum tested concentration of 9000nmol/L. However, sulfamethoxazole exposure did lead to a significant stimulation (75% above control level) of the total pigment content of the biofilm already at the lowest tested concentration of 5nmol/L. The stimulation then decreased with increasing concentrations to finally return to control level at 3000nmol/L. No shifts in the relative pigment composition were observed, indicating a generally increased algal biomass without major shifts in community composition.
环丙沙星和磺胺甲恶唑是两种常见的在水环境中检测到的抗生素，但关于它们对自然微生物群落的毒性的信息在很大程度上是缺失的。特别是，对于海洋微生物，目前还没有数据。因此，本研究的目的是评估环丙沙星和磺胺甲恶唑对自然海洋生物膜（周丛生物）的慢性毒性，生物膜是由多种细菌和藻类组成的复杂生态群落。生物膜是沿着瑞典西海岸采集的，然后在一个半静态系统中暴露于一系列抗生素浓度下，持续 4 天。使用 Biolog Ecoplates 评估生物膜中细菌部分的群落的效应，Biolog Ecoplates 反映了细菌群落的总呼吸和功能多样性。结果表明，两种抗生素都表现出明显的浓度-效应关系，对于环丙沙星和磺胺甲恶唑，抑制总碳源利用的 EC10 和 EC50 值分别为 46.1nmol/L 和 490.7nmol/L，56nmol/L 和 1073nmol/L。环丙沙星的 NOEC 为 26nmol/L，最小显著差异为 19.24%，磺胺甲恶唑的 NOEC 为 140nmol/L，最小显著差异为 14%。对整个碳源利用模式的多元数据分析证实了这些结果。这些数据表明，磺胺甲恶唑导致碳源利用的普遍减少，而环丙沙星暴露导致碳利用模式在 20-50%效应区域的重新排列。这与环丙沙星对某些细菌物种的更高特异性相对应。通过分析光合色素的含量和组成来评估对群落中藻类部分的影响，在最高测试浓度 9000nmol/L 下，环丙沙星和磺胺甲恶唑都没有引起任何抑制作用。然而，磺胺甲恶唑暴露在最低测试浓度 5nmol/L 时就显著刺激了生物膜的总色素含量（比对照水平高 75%）。随着浓度的增加，刺激作用逐渐降低，最终在 3000nmol/L 时恢复到对照水平。没有观察到相对色素组成的变化，这表明藻类生物量普遍增加，而群落组成没有重大变化。
