Methicillin-resistant Staphylococcus aureus (MRSA) is considered a priority pathogen causing high mortality that requires effective control measures. This study aimed to detect the presence of antibiotic-biosynthetic genes and to evaluate the anti-MRSA activity of two strains of endophytic Bacillus velezensis isolated from Archidendron pauciflorum. PCR-based screening showed that B. velezensis strains, such as DJ4 and DJ9 possessed six antibiotic-biosynthetic genes, namely MlnA, DhbE, BacD, DfnD, SrfA, and BaeR. According to the preliminary test conducted using disc-diffusion assay, metabolite extracts from these strains have anti-MRSA activity with clear zone diameters of 13.00 ± 0.82 mm, and 17.33 ± 0.47 mm, respectively. Extract from DJ9 strain was more active to MRSA, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 62.50 µg/mL and 250 µg/mL, respectively. Furthermore, a bactericidal effect was observed, as evidenced by MBC/MIC ratio of four. Both DJ9 and DJ4 extracts showed a dose-dependent inhibitory effect on MRSA biofilm formation. Furthermore, a maximum inhibition percentage of 60.12 ± 2.5% was shown by DJ9 extract in two-fold MIC. The corresponding extract disrupted MRSA mature biofilms most effectively at 55.74 ± 1.4%. In conclusion, crude extract, particularly the DJ9 strain had significant potential in inhibiting MRSA cell growth, MRSA biofilm formation, and disrupting MRSA mature biofilm in vitro.

耐甲氧西林金黄色葡萄球菌(MRSA) 被认为是导致高死亡率的首要病原体，需要采取有效的控制措施。本研究旨在检测抗生素生物合成基因的存在，并评估从Archidendron pauciflorum中分离的两株内生芽孢杆菌的抗MRSA 活性。基于PCR的筛选表明，贝莱泽博格斯多德菌株（例如DJ4和DJ9）拥有6个抗生素生物合成基因，即MlnA 、DhbE 、BacD 、DfnD、SrfA和BaeR。根据纸片扩散法初步测试，这些菌株的代谢物提取物具有抗MRSA活性，其净区直径分别为13.00±0.82mm和17.33±0.47mm。 DJ9菌株提取物对MRSA的活性更强，最低抑菌浓度（MIC）和最低杀菌浓度（MBC）值分别为62.50 µg/mL和250 µg/mL。此外，观察到杀菌效果，MBC/MIC 比率为 4 证明了这一点。 DJ9 和 DJ4 提取物均显示出对 MRSA 生物膜形成的剂量依赖性抑制作用。此外，DJ9 提取物在两倍 MIC 中显示出最大抑制百分比为 60.12 ± 2.5%。相应的提取物最有效地破坏 MRSA 成熟生物膜，效率为 55.74 ± 1.4%。总之，粗提物，特别是DJ9菌株在体外抑制MRSA细胞生长、MRSA生物膜形成和破坏MRSA成熟生物膜方面具有显着潜力。