Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.
Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA.
mBio. 2023 Jun 27;14(3):e0065923. doi: 10.1128/mbio.00659-23. Epub 2023 Apr 17.
The continued challenges of the COVID-19 pandemic combined with the growing problem of antimicrobial-resistant bacterial infections has severely impacted global health. Specifically, the Gram-negative pathogen Klebsiella pneumoniae is one of the most prevalent causes of secondary bacterial infection in COVID-19 patients, with approximately an 83% mortality rate observed among COVID-19 patients with these bacterial coinfections. K. pneumoniae belongs to the ESKAPE group of pathogens, a group that commonly gives rise to severe infections that are often life-threatening. Recently, K. pneumoniae carbapenemase (KPC)-producing K. pneumoniae has drawn wide public attention, as the mortality rate for this infection can be as high as 71%. The most predominant and clinically important multidrug efflux system in K. pneumoniae is the acriflavine resistance B (AcrB) multidrug efflux pump. This pump mediates resistance to different classes of structurally diverse antimicrobial agents, including quinolones, β-lactams, tetracyclines, macrolides, aminoglycosides, and chloramphenicol. We here report single-particle cryo-electron microscopy (cryo-EM) structures of K. pneumoniae AcrB, in both the absence and the presence of the antibiotic erythromycin. These structures allow us to elucidate specific pump-drug interactions and pinpoint exactly how this pump recognizes antibiotics. Klebsiella pneumoniae has emerged as one of the most problematic and highly antibiotic-resistant pathogens worldwide. It is the second most common causative agent involved in secondary bacterial infection in COVID-19 patients. K. pneumoniae carbapenemase (KPC)-producing K. pneumoniae is a major concern in global public health because of the high mortality rate of this infection. Its drug resistance is due, in a significant part, to active efflux of these bactericides, a major mechanism that K. pneumoniae uses to resist to the action of multiple classes of antibiotics. Here, we report cryo-electron microscopy (cryo-EM) structures of the prevalent and clinically important K. pneumoniae AcrB multidrug efflux pump, in both the absence and the presence of the erythromycin antibiotic. These structures allow us to understand the action mechanism for drug recognition in this pump. Our studies will ultimately inform an era in structure-guided drug design to combat multidrug resistance in these Gram-negative pathogens.
新型冠状病毒肺炎大流行的持续挑战，加上抗菌药物耐药细菌感染问题日益严重，严重影响了全球健康。具体来说，革兰氏阴性病原体肺炎克雷伯菌是导致 COVID-19 患者继发细菌感染的最常见病原体之一，在合并这些细菌感染的 COVID-19 患者中，约有 83%的死亡率。肺炎克雷伯菌属于 ESKAPE 病原体群，该病原体群通常引起严重感染，往往危及生命。最近，产碳青霉烯酶肺炎克雷伯菌（KPC）引起了广泛的公众关注，因为这种感染的死亡率可高达 71%。肺炎克雷伯菌中最主要和临床上最重要的多药外排系统是吖啶黄素抗性 B（AcrB）多药外排泵。该泵介导对不同结构多样的抗菌药物的耐药性，包括喹诺酮类、β-内酰胺类、四环素类、大环内酯类、氨基糖苷类和氯霉素。我们在此报告肺炎克雷伯菌 AcrB 的单颗粒冷冻电镜（cryo-EM）结构，分别在没有和存在抗生素红霉素的情况下。这些结构使我们能够阐明特定的泵-药物相互作用，并准确指出该泵如何识别抗生素。
肺炎克雷伯菌已成为全球最具问题和高度耐药性的病原体之一。它是 COVID-19 患者继发细菌感染的第二大常见病原体。产碳青霉烯酶肺炎克雷伯菌（KPC）的肺炎克雷伯菌是全球公共卫生的主要关注点，因为这种感染的死亡率很高。其耐药性部分归因于这些杀菌剂的主动外排，这是肺炎克雷伯菌抵抗多类抗生素作用的主要机制。在此，我们报告了流行且临床上重要的肺炎克雷伯菌 AcrB 多药外排泵的 cryo-EM 结构，分别在没有和存在红霉素抗生素的情况下。这些结构使我们能够理解该泵中药物识别的作用机制。我们的研究将最终为基于结构的药物设计时代提供信息，以对抗这些革兰氏阴性病原体的多药耐药性。
