Morales-Ruíz Leslie-Mariana, Salazar-Gómez Anuar, Hernández-Rangel Álvaro-Omar, Kerber-Díaz Jeniffer-Chris, Vargas-Díaz María-Elena, Antonio-Ibarra J, Rojas-Rojas Fernando-Uriel, Estrada-de Los Santos Paulina
Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México.
Escuela Nacional de Estudios Superiores Unidad León, Universidad Nacional Autónoma de México, León, Guanajuato, México.
PLoS One. 2025 Jun 30;20(6):e0326906. doi: 10.1371/journal.pone.0326906. eCollection 2025.
The genus Burkholderia is currently recognized for producing several antimicrobial compounds with potential applications in developing novel treatments for infectious diseases, including those caused by multidrug-resistant (MDR) bacteria. This study aimed to investigate the ability of Burkholderia orbicola TAtl-371T and CACua-24 to inhibit the growth of MDR human pathogens and to analyze the chemical composition of active extracts from cultures of these strains to identify putative compounds associated with their activity. The double-layer agar technique was used to evaluate the antimicrobial activity of B. orbicola strains. Sequential solvent extraction with hexane, dichloromethane, ethyl acetate, and methanol was conducted on B. orbicola cultures, and the active extract was analyzed by bioautography and fractionated using preparative thin-layer chromatography. Putative antimicrobials in the active fraction were identified through 1H, 13C NMR, and mass spectrometry. B. orbicola strains inhibited several MDR strains of Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus on double-layer agar probes, displaying inhibition halos ranging from 5 to 41 mm. The hexane extract showed the best inhibitory activity against MDR strains, except for P. aeruginosa strains. Analysis through thin-layer chromatography and bioautography revealed a tailing spot with antimicrobial activity. The spectroscopic analysis of this tailing spot revealed the presence of the siderophore fragin. This fragin-containing fraction inhibited the MDR A. baumannii (1024 µg/mL), K. pneumoniae 903137 (128 µg/mL), E. coli (256 µg/mL), and S. aureus (128 µg/mL), but no effect was observed against P. aeruginosa. This fraction also inhibited yeasts of the species Candida albicans and Nakaseomyces glabratus, suggesting an antimicrobial spectrum that extends beyond MDR bacteria. The genomic sequence analysis of strains TAtl-371T and CACua-24 revealed a cluster of 7 genes, resulting in the same organization and over 99% similarity to the fragin genes reported for Burkholderia cenocepacia H111. This study highlights the potential of B. orbicola to produce fragin and its potential activity against MDR bacteria that affect human health worldwide.
伯克霍尔德氏菌属目前因能产生多种抗菌化合物而受到关注，这些化合物在开发针对传染病的新型治疗方法方面具有潜在应用价值，包括由多重耐药（MDR）细菌引起的传染病。本研究旨在调查圆孢伯克霍尔德氏菌TAtl - 371T和CACua - 24抑制MDR人类病原体生长的能力，并分析这些菌株培养物中活性提取物的化学成分，以鉴定与其活性相关的假定化合物。采用双层琼脂技术评估圆孢伯克霍尔德氏菌菌株的抗菌活性。对圆孢伯克霍尔德氏菌培养物依次用己烷、二氯甲烷、乙酸乙酯和甲醇进行溶剂萃取，通过生物自显影分析活性提取物，并使用制备型薄层色谱进行分离。通过1H、13C核磁共振和质谱鉴定活性组分中的假定抗菌剂。在双层琼脂探针上，圆孢伯克霍尔德氏菌菌株抑制了几种鲍曼不动杆菌、肺炎克雷伯菌、铜绿假单胞菌、大肠杆菌和金黄色葡萄球菌的MDR菌株，抑菌圈范围为5至41毫米。除铜绿假单胞菌菌株外，己烷提取物对MDR菌株显示出最佳抑制活性。通过薄层色谱和生物自显影分析发现一个具有抗菌活性的拖尾斑点。对该拖尾斑点的光谱分析表明存在铁载体弗拉金。这种含弗拉金的组分抑制了MDR鲍曼不动杆菌（1024 µg/mL）、肺炎克雷伯菌903137（128 µg/mL）、大肠杆菌（256 µg/mL）和金黄色葡萄球菌（128 µg/mL），但对铜绿假单胞菌没有效果。该组分还抑制了白色念珠菌和光滑假丝酵母属的酵母，表明其抗菌谱超出了MDR细菌。对TAtl - 371T和CACua - 24菌株的基因组序列分析揭示了一个由7个基因组成的基因簇，其组织形式相同，与报道的洋葱伯克霍尔德氏菌H111的弗拉金基因相似度超过99%。本研究突出了圆孢伯克霍尔德氏菌产生弗拉金的潜力及其对全球影响人类健康的MDR细菌的潜在活性。
