National Institute of Genetic Engineering and Biotechnology (NIGEB), P. O. Box 14155-6343, Tehran, Iran.
Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran.
Sci Rep. 2022 Sep 1;12(1):14833. doi: 10.1038/s41598-022-19103-w.
A group of biosurfactants, called rhamnolipids, have been shown to have antibacterial and antibiofilm activity against multidrug-resistant bacteria. Here, we examined the effect of rhamnolipid biosurfactants extracted from Pseudomonas aeruginosa MA01 on cell growth/viability, biofilm formation, and membrane permeability of methicillin-resistant Staphylococcus aureus (MRSA) ATCC6538 bacterial cells. The results obtained from flow cytometry analysis showed that by increasing the concentration of rhamnolipid from 30 to 120 mg/mL, the cell viability decreased by about 70%, and the cell membrane permeability increased by approximately 20%. In fact, increasing rhamnolipid concentration was directly related to cell membrane permeability and inversely related to cell survival. Microtiter plate biofilm assay and laser scanning confocal microscopy analysis revealed that rhamnolipid, at a concentration of 60 mg/mL, exerts a reducing effect on the biofilm formation of Staphylococcus aureus. Real-time PCR analysis for monitoring the relative changes in the expression of agrA, agrC, icaA, and icaD genes involved in biofilm formation and related to the quorum-sensing pathway after treatment with rhamnolipid indicated a reduced expression level of these genes, as well as sortase A gene. The results of the present study deepen our knowledge regarding the use of microbial natural products as promising candidates for therapeutic applications.
一组被称为鼠李糖脂的生物表面活性剂已被证明对多药耐药菌具有抗菌和抗生物膜活性。在这里，我们研究了从铜绿假单胞菌 MA01 中提取的鼠李糖脂生物表面活性剂对耐甲氧西林金黄色葡萄球菌 (MRSA) ATCC6538 细菌细胞的细胞生长/活力、生物膜形成和膜通透性的影响。流式细胞术分析的结果表明，通过将鼠李糖脂的浓度从 30 增加到 120mg/mL，细胞活力降低了约 70%，而细胞膜通透性增加了约 20%。事实上，增加鼠李糖脂浓度与细胞膜通透性直接相关，与细胞存活率成反比。微量滴定板生物膜测定和激光共聚焦显微镜分析表明，鼠李糖脂在 60mg/mL 的浓度下对金黄色葡萄球菌的生物膜形成具有降低作用。用鼠李糖脂处理后，通过实时 PCR 分析监测与生物膜形成和群体感应途径相关的 agrA、agrC、icaA 和 icaD 基因的相对变化，这些基因以及转谷氨酰胺酶 A 基因的表达水平降低。本研究的结果加深了我们对微生物天然产物作为有前途的治疗应用候选物的认识。
