Lo-Ellen Park Secondary School, Sudbury, Canada.
Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada.
J Med Microbiol. 2020 Aug;69(8):1049-1061. doi: 10.1099/jmm.0.001226.
Metal exposure is an important factor for inducing antibiotic resistance in bacteria. Dandelion extracts have been used for centuries in traditional Chinese and Native American medicine. We assessed the effects of dandelion water extracts and taraxasterol on heavy metal-induced antibiotic resistance in as well as the underlying mechanisms. Dandelion extracts were obtained through 4 h of boiling in distilled water. Bacterial growth was monitored with a spectrophotometer. Biochemical assays were performed to assess the activities and gene transcriptions of β-lactamase and acetyltransferase. Oxidative stress was determined using an oxidation-sensitive probe, HDCFDA. The present study demonstrated that higher concentrations of nickel (>5 µg ml), cadmium (>0.1 µg ml), arsenic (>0.1 µg ml) and copper (>5 µg ml) significantly inhibited the growth of . Lower concentrations of nickel (0.5 µg ml), cadmium (0.05 µg ml) and arsenic (0.05 µg ml) had no effect on bacterial growth, but helped the bacteria become resistant to two antibiotics, kanamycin and ampicillin. The addition of dandelion root extracts and taraxasterol significantly reversed the antibiotic resistance induced by these heavy metals. The supplements of antibiotics and cadmium generated synergistic effects on the activities of β-lactamase and acetyltransferase (two antibiotic resistance-related proteins), which were significantly blocked by either dandelion root extract or taraxasterol. In contrast, oxidative stress was not involved in the preventative roles of dandelion root extracts and taraxasterol in heavy metal-induced antibiotic resistance. This study suggests that heavy metals induce bacterial antibiotic resistance and dandelion root extracts and taraxasterol could be used to help reverse bacterial resistance to antibiotics.
金属暴露是诱导细菌产生抗生素耐药性的一个重要因素。蒲公英提取物在中医疗法和美洲原住民医学中已使用了数个世纪。我们评估了蒲公英水提取物和蒲公英甾醇对重金属诱导的 抗生素耐药性的影响，以及潜在的机制。蒲公英提取物通过在蒸馏水中煮沸 4 小时获得。使用分光光度计监测细菌生长。进行生化测定以评估β-内酰胺酶和乙酰转移酶的活性和基因转录。使用氧化敏感探针 HDCFDA 测定氧化应激。本研究表明，较高浓度的镍（>5 µg ml）、镉（>0.1 µg ml）、砷（>0.1 µg ml）和铜（>5 µg ml）显著抑制 的生长。较低浓度的镍（0.5 µg ml）、镉（0.05 µg ml）和砷（0.05 µg ml）对细菌生长没有影响，但有助于细菌对两种抗生素，卡那霉素和氨苄西林产生耐药性。添加蒲公英根提取物和蒲公英甾醇可显著逆转这些重金属诱导的抗生素耐药性。抗生素和镉的添加对β-内酰胺酶和乙酰转移酶（两种与抗生素耐药性相关的蛋白质）的活性产生协同作用，这两种作用均被蒲公英根提取物或蒲公英甾醇显著阻断。相比之下，氧化应激未参与蒲公英根提取物和蒲公英甾醇在重金属诱导的抗生素耐药性中的预防作用。这项研究表明，重金属会诱导细菌产生抗生素耐药性，蒲公英根提取物和蒲公英甾醇可用于帮助逆转细菌对抗生素的耐药性。
