Lawrence J R, Zhu B, Swerhone G D W, Topp E, Roy J, Wassenaar L I, Rema T, Korber D R
Environment Canada, 11 Innovation Blvd., Saskatoon, Saskatchewan, Canada S7N 3H5.
Appl Environ Microbiol. 2008 Jun;74(11):3541-50. doi: 10.1128/AEM.02879-07. Epub 2008 Mar 31.
Chlorhexidine is a common-use antibacterial agent found in a range of personal-care products. We used rotating annular reactors to cultivate river biofilms under the influence of chlorhexidine or its molar equivalent in nutrients. Studies of the degradation of [(14)C]chlorhexidine demonstrated that no mineralization of the compound occurred. During studies with 100 microg liter(-1) chlorhexidine, significant changes were observed in the protozoan and micrometazoan populations, the algal and cyanobacterial biomass, the bacterial biomass, and carbon utilization. Denaturing gradient gel electrophoresis (DGGE) in combination with statistical analyses showed that the communities developing under control and 100 microg liter(-1) chlorhexidine were significantly different. At 10 microg liter(-1) chlorhexidine, there was significantly increased algal and cyanobacterial biomass while the bacterial biomass was not significantly affected (P < 0.05). No significant effects on protozoan or metazoan grazing were detected at the 10-microg liter(-1) chlorhexidine level. Fluorescent in situ hybridization indicated a significant reduction in the abundance of betaproteobacteria and gammaproteobacteria (P < 0.05). Archaeal cell counts were significantly reduced by both chlorhexidine and nutrient treatments. DGGE and statistical analyses indicated that 10 microg liter(-1) chlorhexidine and molar equivalent nutrient treatments were significantly different from control communities. In contrast to community level observations, toxicological testing with a panel of cyanobacteria, algae, and protozoa indicated no detectable effects at 10, 50, and 100 microg liter(-1) chlorhexidine. Thus, community level assessment indicated a risk of low levels of chlorhexidine in aquatic habitats while conventional approaches did not.
洗必泰是一种常见的抗菌剂，存在于一系列个人护理产品中。我们使用旋转环形反应器在洗必泰或其摩尔当量存在于营养物质中的情况下培养河流生物膜。对[¹⁴C]洗必泰降解的研究表明，该化合物没有发生矿化。在用100微克/升洗必泰进行的研究中，原生动物和小型后生动物种群、藻类和蓝细菌生物量、细菌生物量以及碳利用情况都出现了显著变化。变性梯度凝胶电泳（DGGE）结合统计分析表明，在对照条件下和100微克/升洗必泰条件下形成的群落有显著差异。在10微克/升洗必泰时，藻类和蓝细菌生物量显著增加，而细菌生物量没有受到显著影响（P < 0.05）。在10微克/升洗必泰水平下，未检测到对原生动物或后生动物捕食的显著影响。荧光原位杂交表明β-变形菌和γ-变形菌的丰度显著降低（P < 0.05）。洗必泰和营养处理都显著降低了古菌细胞数量。DGGE和统计分析表明，10微克/升洗必泰和摩尔当量营养处理与对照群落有显著差异。与群落水平的观察结果相反，对一组蓝细菌、藻类和原生动物进行的毒理学测试表明，在10、50和100微克/升洗必泰时没有可检测到的影响。因此，群落水平评估表明水生栖息地中低水平的洗必泰存在风险，而传统方法则未显示出这种风险。
