ABSTRACT

The global spread of multidrug-resistant strains has prompted the scientific community to explore novel sources of chemicals with antimicrobial activity. The aim of the study was to examine the antimicrobial activity in vitro of 28 extracts against carbapenem-producing Klebsiella pneumoniae, individually and in combination with antibiotics and in vivo toxicological assessment of the most active product. The multi-resistant K. pneumoniae strain was submitted for phenotypic and molecular characterization. The antibacterial activity of 28 plant extracts was evaluated alone and in combination with antibiotics against this strain through the agar disk diffusion. Of these, 16 extracts showed synergism against carbapenem-producing K. pneumoniae, being that B. crassifolia extract exhibited synergism with three antibiotics. Based on this assessment, B. crassifolia-extract-induced toxicity on Swiss male mice was evaluated by administering this extract and subsequently determining apoptosis and splenic phagocytosis using the comet and micronucleus assays. The results of this study showed that B. crassifolia extract had synergistic activity promising and groups treated with B. crassifolia exhibited no genotoxic or mutagenic activity, indicating that B. crassifolia extract exerted beneficial effects and appeared safe to use at the studied concentrations.

摘要

耐多药菌株的全球传播促使科学界探索具有抗菌活性的化学新来源。该研究的目的是单独和与抗生素结合使用，对28种提取物对产碳青霉烯的肺炎克雷伯菌的体外抗菌活性进行检测，并对活性最强的产品进行体内毒理学评估。提交了多抗性肺炎克雷伯菌菌株用于表型和分子表征。通过琼脂圆盘扩散，单独评估了28种植物提取物的抗菌活性，并结合了抗生素对该菌株的抗菌活性。其中，有16种提取物对产生碳青霉烯有协同作用肺炎克雷伯氏菌（B. crassifolia）提取物表现出与三种抗生素的协同作用。基于该评估，通过施用该提取物并随后使用彗星和微核试验确定凋亡和脾吞噬作用，评估了啤酒花提取物对瑞士雄性小鼠的毒性。这项研究的结果表明，景天芽孢杆菌提取物具有协同活性，并且用景天芽孢杆菌治疗的组没有遗传毒性或诱变活性，表明景天芽孢杆菌提取物发挥有益作用，并且在所研究的浓度下似乎可以安全使用。