It is urgent to find new antibiotic classes with activity against multidrug-resistant (MDR) Gram-negative pathogens as the pipeline of antibiotics is essentially empty. Modified pyrrolobenzodiazepines with a C8-linked aliphatic heterocycle provide a new class of broad-spectrum antibacterial agents with activity against MDR Gram-negative bacteria, including WHO priority pathogens. The structure–activity relationship established that the third ring was particularly important for Gram-negative activity. Minimum inhibitory concentrations for the lead compounds ranged from 0.125 to 2 mg/L for MDR Gram-negative, excluding Pseudomonas aeruginosa, and between 0.03 and 1 mg/L for MDR Gram-positive species. The lead compounds were rapidly bactericidal with >5 log reduction in viable count within 4 h for Acinetobacter baumannii and Klebsiella pneumoniae. The lead compound inhibited DNA gyrase in gel-based assays, with an IC₅₀ of 3.16 ± 1.36 mg/L. This study provides a new chemical scaffold for developing novel broad-spectrum antibiotics which can help replenish the pipeline of antibiotics.

中文翻译：

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新型的广谱抗生素，含有吡咯并苯二氮杂卓环，具有抗多药耐药革兰氏阴性菌的活性。

迫切需要找到对多药耐药（MDR）革兰氏阴性病原体具有活性的新抗生素类别，因为抗生素的生产线基本上是空的。具有C8连接的脂族杂环的改性吡咯并苯并二氮杂卓可提供一类新型的广谱抗菌剂，其对包括世界卫生组织优先病原体在内的MDR革兰氏阴性细菌具有活性。构效关系确定第三环对于革兰氏阴性活性特别重要。除铜绿假单胞菌外，对于MDR革兰氏阴性，先导化合物的最低抑菌浓度范围为0.125至2 mg / L，对于MDR革兰氏阳性菌种，最低抑菌浓度为0.03至1 mg / L。铅化合物可快速杀菌，可在4小时内将活菌数减少> 5 log鲍曼不动杆菌和肺炎克雷伯菌。铅化合物在基于凝胶的测定中抑制DNA促旋酶，IC ₅₀为3.16±1.36 mg / L。这项研究为开发新型广谱抗生素提供了一种新的化学支架，可以帮助补充抗生素。