Department of Biological Sciences, Columbia University, New York, NY, 10027, USA.
Department of Chemistry, Columbia University, New York, NY, 10027, USA.
Nat Commun. 2019 Feb 15;10(1):762. doi: 10.1038/s41467-019-08733-w.
Antibiotic efficacy can be antagonized by bioactive metabolites and other drugs present at infection sites. Pseudomonas aeruginosa, a common cause of biofilm-based infections, releases metabolites called phenazines that accept electrons to support cellular redox balancing. Here, we find that phenazines promote tolerance to clinically relevant antibiotics, such as ciprofloxacin, in P. aeruginosa biofilms and that this effect depends on the carbon source provided for growth. We couple stable isotope labeling with stimulated Raman scattering microscopy to visualize biofilm metabolic activity in situ. This approach shows that phenazines promote metabolism in microaerobic biofilm regions and influence metabolic responses to ciprofloxacin treatment. Consistent with roles of specific respiratory complexes in supporting phenazine utilization in biofilms, phenazine-dependent survival on ciprofloxacin is diminished in mutants lacking these enzymes. Our work introduces a technique for the chemical imaging of biosynthetic activity in biofilms and highlights complex interactions between bacterial products, their effects on biofilm metabolism, and the antibiotics we use to treat infections.
生物活性代谢物和其他存在于感染部位的药物会对抗抗生素的疗效。铜绿假单胞菌是生物膜感染的常见原因，它会释放被称为吩嗪的代谢物，这些代谢物接受电子以支持细胞氧化还原平衡。在这里，我们发现吩嗪可增强铜绿假单胞菌生物膜中临床相关抗生素（如环丙沙星）的耐受性，并且这种作用取决于生长提供的碳源。我们将稳定同位素标记与受激拉曼散射显微镜相结合，以原位可视化生物膜代谢活性。这种方法表明，吩嗪可促进微需氧生物膜区域的代谢，并影响对环丙沙星治疗的代谢反应。与特定呼吸复合物在支持生物膜中吩嗪利用中的作用一致，缺乏这些酶的突变体中，依赖吩嗪的生存能力会降低，对环丙沙星的敏感性降低。我们的工作介绍了一种用于生物膜中生物合成活性的化学成像技术，并强调了细菌产物之间的复杂相互作用、它们对生物膜代谢的影响以及我们用于治疗感染的抗生素。
