Kurenbach Brigitta, Gibson Paddy S, Hill Amy M, Bitzer Adam S, Silby Mark W, Godsoe William, Heinemann Jack A
School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
Centre for Integrated Research in Biosafety and Centre for Integrative Ecology, University of Canterbury, Christchurch, New Zealand.
Microbiology (Reading). 2017 Dec;163(12):1791-1801. doi: 10.1099/mic.0.000573.
Herbicides are frequently released into both rural and urban environments. Commercial herbicide formulations induce adaptive changes in the way bacteria respond to antibiotics. sv. Typhimurium and were exposed to common co-formulants of formulations, and sv. Typhimurium was exposed to active ingredients dicamba, 2,4-D and glyphosate to determine what ingredients of the commercial formulations caused this effect. Co-formulants Tween80 and carboxymethyl cellulose induced changes in response, but the pattern of the responses differed from the active ingredients, and effect sizes were smaller. A commercial wetting agent did not affect antibiotic responses. Active ingredients induced changes in antibiotic responses similar to those caused by complete formulations. This occurred at or below recommended application concentrations. Targeted deletion of efflux pump genes largely neutralized the adaptive response in the cases of increased survival in antibiotics, indicating that the biochemistry of induced resistance was the same for formulations and specific ingredients. We found that glyphosate, dicamba, and 2,4-D, as well as co-formulants in commercial herbicides, induced a change in susceptibility of the potentially pathogenic bacteria and to multiple antibiotics. This was measured using the efficiency of plating (EOP), the relative survival of the bacteria when exposed to herbicide and antibiotic, or just antibiotic, compared to survival on permissive media. This work will help to inform the use of non-medicinal chemical agents that induce changes in antibiotic responses.
除草剂经常被释放到农村和城市环境中。商业除草剂配方会诱导细菌对抗生素的反应方式发生适应性变化。鼠伤寒沙门氏菌和其他菌株暴露于配方的常见辅助剂中，鼠伤寒沙门氏菌还暴露于活性成分麦草畏、2,4-滴和草甘膦中，以确定商业配方中的哪些成分导致了这种效应。辅助剂吐温80和羧甲基纤维素诱导了反应变化，但反应模式与活性成分不同，且效应大小较小。一种商业湿润剂不影响抗生素反应。活性成分诱导的抗生素反应变化与完整配方引起的变化相似。这种情况发生在推荐施用浓度或低于该浓度时。在抗生素存活增加的情况下，有针对性地删除外排泵基因在很大程度上中和了适应性反应，这表明配方和特定成分诱导抗性的生物化学过程是相同的。我们发现，草甘膦、麦草畏和2,4-滴以及商业除草剂中的辅助剂会导致潜在病原菌对多种抗生素的敏感性发生变化。这是通过平板接种效率（EOP）来衡量的，即与在允许培养基上的存活情况相比，细菌在接触除草剂和抗生素或仅接触抗生素时的相对存活率。这项工作将有助于为使用能诱导抗生素反应变化的非药用化学试剂提供参考。
