Bioprocess and Environment Group, LASIME Laboratory, Agadir Superior School of Technology, Ibn Zohr University, Agadir, Morocco.
Laboratory of Microbial Biotechnology and Vegetal Protection, Faculty of Sciences, Ibn Zohr University, Agadir, Morocco.
Curr Microbiol. 2023 May 18;80(7):216. doi: 10.1007/s00284-023-03326-9.
Enterococcus species are commensal organisms of the gastrointestinal tract and can also be isolated from traditional food products. They are used as probiotics in animals and less often in humans. This study aimed to investigate the antibacterial and anti-adhesive activities of twelve food-origin Enterococcus spp. biofilms on stainless steel AISI 316 L against foodborne pathogens, including Listeria monocytogenes CECT4032, Pseudomonas aeruginosa ATCC27853, and Escherichia coli ATCC25922. The antimicrobial and co-aggregation abilities of Enterococcus spp. were evaluated using spots-agar test and spectrophotometry aggregation assay, respectively. The anti-adhesive activity of selected strains on pathogenic bacteria was tested using serial dilution technique. Enterococci strains in planktonic mode showed strong inhibition activity against different pathogens tested with a significant difference in co-aggregation capacity. Moreover, L. monocytogenes and E. coli presented a low auto-aggregation rate compared to P. aeruginosa, which showed an amount of 11.25%. Scanning electron microscopy (SEM) revealed that biofilm biomass of Enterococcus spp. increased after 10 days. The thick layer of enterococci biofilms on AISI 316 L caused a low adhesion of L. monocytogenes, resulting in a reduction of approximately 2.8 log CFU/cm² for some selected strains. Additionally, Enterococcus monocultures' biofilms were more efficient than polymicrobial cultures (a cocktail of enterococci strains) in controlling pathogen adhesion. These results indicate that monocultures of Enterococcus spp. biofilms could be used to prevent the adhesion of pathogenic bacteria on AISI 316 L.
肠球菌属是胃肠道的共生菌，也可从传统食品中分离出来。它们被用作动物的益生菌，在人类中使用较少。本研究旨在研究 12 种食品源肠球菌属生物膜对不锈钢 AISI 316L 的抗菌和抗黏附活性，以对抗食源性病原体，包括单核细胞增生李斯特菌 CECT4032、铜绿假单胞菌 ATCC27853 和大肠杆菌 ATCC25922。使用点琼脂试验和分光光度聚集测定法分别评估肠球菌属的抗菌和共聚能力。使用连续稀释技术测试选定菌株对病原菌的抗黏附活性。浮游模式的肠球菌菌株对不同的测试病原体表现出强烈的抑制活性，其共聚能力存在显著差异。此外，与铜绿假单胞菌相比，单核细胞增生李斯特菌和大肠杆菌的自聚集率较低，分别为 11.25%。扫描电子显微镜 (SEM) 显示，肠球菌属生物膜的生物量在 10 天后增加。在 AISI 316L 上，肠球菌生物膜的厚层导致单核细胞增生李斯特菌的黏附减少，对于一些选定的菌株，减少了约 2.8 log CFU/cm²。此外，肠球菌单培养物的生物膜比多培养物（肠球菌菌株的混合物）更有效地控制病原体的黏附。这些结果表明，肠球菌属生物膜的单培养物可用于防止病原菌在 AISI 316L 上的黏附。
