Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.
Division of Biological and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, USA.
mSystems. 2024 Nov 19;9(11):e0129524. doi: 10.1128/msystems.01295-24. Epub 2024 Oct 29.
Bacterial persistence profoundly impacts biofilms, infections, and antibiotic effectiveness. Persister formation can be substantially promoted by nutrient shift, which commonly exists in natural environments. However, mechanisms that promote persister formation remain poorly understood. Here, we investigated the persistence frequency of after switching from various carbon sources to fatty acid and observed drastically different survival rates. While more than 99.9% of cells died during a 24-hour ampicillin (AMP) treatment after the glycerol to oleic acid (GLY → OA + AMP) shift, a surprising 56% of cells survived the same antibiotic treatment after the glucose to oleic acid (GLU → OOA + AMP) shift. Using a combination of single-cell imaging and time-lapse microscopy, we discovered that the induction of high levels of reactive oxygen species (ROS) by AMP is the primary mechanism of cell killing after switching from gluconeogenic carbons to OA + AMP. Moreover, the timing of the ROS burst is highly correlated ( = 0.91) with the start of the rapid killing phase in the time-kill curves for all gluconeogenic carbons. However, ROS did not accumulate to lethal levels after the GLU → OA + AMP shift. We also found that the overexpression of the oxidative stress regulator and ROS detoxification enzymes strongly affects the amounts of ROS and the persistence frequency following the nutritional shift. These findings elucidate the different persister frequencies resulting from various nutrient shifts and underscore the pivotal role of ROS. Our study provides insights into bacterial persistence mechanisms, holding promise for targeted therapeutic interventions combating bacterial resistance effectively.
This research delves into the intriguing realm of bacterial persistence and its profound implications for biofilms, infections, and antibiotic efficacy. The study focuses on and how the switch from different carbon sources to fatty acids influences the formation of persister-resilient bacterial cells resistant to antibiotics. The findings reveal a striking variation in survival rates, with a significant number of cells surviving ampicillin treatment after transitioning from glucose to oleic acid. The key revelation is the role of reactive oxygen species (ROS) in cell killing, particularly after switching from gluconeogenic carbons. The timing of ROS bursts aligns with the rapid killing phase, highlighting the critical impact of oxidative stress regulation on persistence frequency. This research provides valuable insights into bacterial persistence mechanisms, offering potential avenues for targeted therapeutic interventions to combat bacterial resistance effectively.
细菌持久力对生物膜、感染和抗生素效果有深远影响。营养物质的转移可以极大地促进持久菌的形成，而这种转移在自然环境中很常见。然而，促进持久菌形成的机制仍知之甚少。在这里，我们研究了从各种碳源切换到脂肪酸后 的持久频率，并观察到了截然不同的存活率。在甘油到油酸（GLY→OA+AMP）转换后，氨苄青霉素（AMP）治疗 24 小时内，超过 99.9%的细胞死亡，但令人惊讶的是，在葡萄糖到油酸（GLU→OOA+AMP）转换后，有 56%的细胞在相同的抗生素治疗中存活下来。我们结合单细胞成像和延时显微镜发现，AMP 诱导的高水平活性氧（ROS）是从糖异生碳源切换到 OA+AMP 后细胞杀伤的主要机制。此外，ROS 爆发的时间与所有糖异生碳源的时间杀伤曲线中快速杀伤阶段的开始高度相关（=0.91）。然而，GLU→OA+AMP 转换后 ROS 并未积累到致命水平。我们还发现，氧化应激调节剂和 ROS 解毒酶的过度表达强烈影响 ROS 的积累量和营养物质转移后的持久频率。这些发现阐明了不同营养物质转移导致的不同持久频率，并强调了 ROS 的关键作用。我们的研究提供了对细菌持久机制的深入了解，为有针对性的治疗干预提供了有希望的方法，以有效对抗细菌耐药性。
这项研究深入探讨了细菌持久力及其对生物膜、感染和抗生素疗效的深远影响。该研究关注的是 ，以及从不同碳源切换到脂肪酸如何影响对抗生素有耐药性的持久菌细胞的形成。研究结果显示，在从葡萄糖切换到油酸后，用氨苄青霉素治疗时，有很大比例的细胞存活下来，这一结果令人惊讶。关键发现是活性氧（ROS）在细胞杀伤中的作用，特别是在从糖异生碳源切换后。ROS 爆发的时间与快速杀伤阶段一致，突出了氧化应激调节对持久频率的关键影响。这项研究为细菌持久机制提供了有价值的见解，为有效对抗细菌耐药性提供了有针对性的治疗干预途径。
