Rai Subecha, Singh Laishram Shantikumar, Liriina Kaikho, Jeyaram Kumaraswamy, Parija Tithi, Sahoo Dinabandhu
Institute of Bioresources and Sustainable Development, Sikkim Centre, DBT, Gangtok, 737102, Tadong, Sikkim, India.
School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Patia, Bhubaneshwar, 751024, Odisha, India.
Sci Rep. 2025 Jun 5;15(1):19863. doi: 10.1038/s41598-025-05333-1.
Endophytic actinomycetes of medicinal plants have recently been in focus for developing novel antimicrobial compounds to combat multidrug-resistant pathogens. In this study, we isolated and characterised endophytic actinomycetes of Panax sokpayensis rhizome traditionally used as medicine in Sikkim-Himalayan region and assessed their antimicrobial activity against multidrug-resistant (MDR) clinical isolates of Staphylococcus aureus. Saccharopolyspora dominated as the endophytic actinomycetes of P. sokpayensis rhizome. However, a novel actinomycete strain PSRA5 belongs to the genus Streptomyces, with the highest genome sequence similarity of 91.54% with its closest relative Streptomyces niveus NCIMB 11891 has shown an effective inhibition of six clinical isolates of MDR S. aureus during disc diffusion assay. Further comparative analysis of cellular fatty acids composition and phenotypic and biochemical characteristics of strain PSRA5 with its phylogenetically closely related strain of S. niveus, classified as representing a novel species of the genus Streptomyces, for which the name Streptomyces panacea sp. nov. is proposed here with type strain PSRA5 (= MCC5238). The minimum inhibition concentration of ethyl acetate crude extract of PSRA5 culture supernatant against MDR S. aureus isolates was 5.5 to 13.5 µg/mL. Further correlation between biosynthetic gene clusters identified by genome search with LC-MS analysis-based chemical profiling of PSRA5 culture extract and antibacterial activity of the representative compounds detected several compounds of aminoglycosides and polyketides with antimicrobial activity against MDR S. aureus isolates. Scanning electron microscope imaging viewed an interesting change in the S. aureus cell morphology with flocs of thread-like biofilm formation in response to the PSRA5 culture crude extract treatment. We conclude that the antimicrobial compounds produced by S. panacea PSRA5 can be further purified, characterised, and evaluated for their mode of action and efficacy against MDR S. aureus for developing novel drugs.
药用植物内生放线菌最近成为开发新型抗菌化合物以对抗多重耐药病原体的研究热点。在本研究中，我们分离并鉴定了锡金 - 喜马拉雅地区传统上用作药物的人参三七根茎内生放线菌，并评估了它们对金黄色葡萄球菌多重耐药（MDR）临床分离株的抗菌活性。糖多孢菌是人参三七根茎内生放线菌的主要类型。然而，一种新型放线菌菌株PSRA5属于链霉菌属，与其最接近的亲缘种雪白链霉菌NCIMB 11891的基因组序列相似度最高为91.54%，在纸片扩散试验中显示出对6株MDR金黄色葡萄球菌临床分离株有有效抑制作用。进一步对菌株PSRA5与其系统发育密切相关的雪白链霉菌菌株的细胞脂肪酸组成、表型和生化特征进行比较分析，将PSRA5分类为代表链霉菌属的一个新物种，为此提出新名称链霉菌属灵丹种。模式菌株为PSRA5（=MCC5238）。PSRA5培养上清液的乙酸乙酯粗提物对MDR金黄色葡萄球菌分离株的最低抑菌浓度为5.5至13.5μg/mL。通过基因组搜索鉴定的生物合成基因簇与基于LC-MS分析的PSRA5培养提取物化学图谱以及检测到的具有抗MDR金黄色葡萄球菌分离株抗菌活性的代表性化合物的抗菌活性之间的进一步相关性，发现了几种具有抗MDR金黄色葡萄球菌分离株抗菌活性的氨基糖苷类和聚酮类化合物。扫描电子显微镜成像观察到，经PSRA5培养粗提物处理后，金黄色葡萄球菌细胞形态发生有趣变化，形成丝状生物膜絮状物。我们得出结论，链霉菌属灵丹PSRA5产生的抗菌化合物可进一步纯化、表征，并评估其对MDR金黄色葡萄球菌的作用方式和疗效，以开发新型药物。
