Our understanding of how microbes respond to micropollutants, such as pesticides, is almost wholly based on single-species responses to individual chemicals. However, in natural environments, microbes experience multiple pollutants simultaneously. Here we perform a matrix of multi-stressor experiments by assaying the growth of model and non-model strains of bacteria in all 255 combinations of 8 chemical stressors (antibiotics, herbicides, fungicides and pesticides). We found that bacterial strains responded in different ways to stressor mixtures, which could not be predicted simply from their phylogenetic relatedness. Increasingly complex chemical mixtures were both more likely to negatively impact bacterial growth in monoculture and more likely to reveal net interactive effects. A mixed co-culture of strains proved more resilient to increasingly complex mixtures and revealed fewer interactions in the growth response. These results show predictability in microbial population responses to chemical stressors and could increase the utility of next-generation eco-toxicological assays.

我们对微生物如何对杀虫剂等微污染物做出反应的理解几乎完全基于单一物种对个别化学物质的反应。然而，在自然环境中，微生物同时经历多种污染物。在这里，我们通过分析模型和非模型细菌菌株在 8 种化学压力源（抗生素、除草剂、杀菌剂和杀虫剂）的所有 255 种组合中的生长情况，进行了多压力源实验矩阵。我们发现细菌菌株对应激混合物以不同的方式做出反应，这不能简单地从它们的系统发育相关性来预测。日益复杂的化学混合物更有可能对单一栽培中的细菌生长产生负面影响，也更有可能揭示净相互作用效应。事实证明，菌株的混合共培养对日益复杂的混合物更具弹性，并且生长反应中的相互作用较少。这些结果显示了微生物群体对化学应激源反应的可预测性，并且可以提高下一代生态毒理学测定的实用性。