Abstract：
Extended-spectrumβ-lactam producing Escherichia coli (ESBL-EC) readily colonizes live poultry and serves as a major source of contamination in retail chicken meat, posing significant threats to public health. This study aims to investigate the impact of inappropriate antibiotic use on the dissemination and exacerbation of antibiotic resistance in ESBL-EC and explore the underlying molecular mechanisms. Through experimental analysis, we propose a hypothesis that inappropriate antibiotic use may exacerbate resistance by affecting vesicle formation and protein secretion. Experimental results demonstrate that under the influence of amoxicillin, the concentration of proteins secreted in outer membrane vehicles (OMVs) by ESBL-EC significantly increases, along with a significant upregulation in the expression of the CTX-M-55-type Extended-spectrum beta-lactamase (CTX-M-55). Proteomic analysis and differential gene knockout experiments identified the key protein YdcZ, associated with OMVs formation and protein transportation in ESBL-EC under amoxicillin treatment. Further investigations reveal direct interactions between YdcZ and other proteins (YdiH and BssR). Upon ydcz gene knockout, a significant decrease in protein concentration within OMVs is observed, accompanied by a noticeable reduction in protection against sensitive bacteria. These findings suggest a critical role of YdcZ in regulating the process of protein transportation to OMVs in ESBL-EC under the influence of amoxicillin. In summary, our research uncovers the significant role of inappropriate antibiotic use in promoting the secretion of OMVs by ESBL-EC, aiding the survival of antibiotic-sensitive bacteria in the vicinity of infection sites. These findings provide new insights into the mechanisms underlying antibiotic-induced bacterial resistance dissemination and offer novel avenues for exploring prevention and control strategies against bacterial resistance propagation.
摘要：
产超广谱β-内酰胺的大肠杆菌（ESBL-EC）很容易在活禽中定殖，并成为零售鸡肉中的主要污染源。对公众健康构成重大威胁。本研究旨在研究不适当的抗生素使用对ESBL-EC中抗生素耐药性传播和加剧的影响，并探讨其潜在的分子机制。通过实验分析,我们提出了一个假设，即不适当的抗生素使用可能会通过影响囊泡形成和蛋白质分泌而加剧耐药性。实验结果表明,在阿莫西林的作用下,ESBL-EC分泌的外膜载体（OMV）中的蛋白质浓度显着增加，同时CTX-M-55型超广谱β-内酰胺酶(CTX-M-55)的表达显著上调。蛋白质组学分析和差异基因敲除实验确定了关键蛋白YdcZ,在阿莫西林治疗下与ESBL-EC中OMV的形成和蛋白质转运有关。进一步的研究揭示了YdcZ和其他蛋白质(YdiH和BssR)之间的直接相互作用。在ydcz基因敲除后，观察到OMV内的蛋白质浓度显着降低，伴随着对敏感细菌的保护显着减少。这些发现表明，在阿莫西林的影响下，YdcZ在调节ESBL-EC中蛋白质转运至OMV的过程中起着关键作用。总之,我们的研究揭示了不适当使用抗生素在促进ESBL-EC分泌OMV中的重要作用，帮助抗生素敏感细菌在感染部位附近的生存。这些发现为抗生素诱导的细菌耐药性传播的潜在机制提供了新的见解，并为探索针对细菌耐药性传播的预防和控制策略提供了新的途径。
