Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, P.O. Box 173980, Bozeman, MT 59717-3980, United States of America.
J Microbiol Methods. 2024 Aug;223:106960. doi: 10.1016/j.mimet.2024.106960. Epub 2024 May 22.
The CDC Biofilm Reactor method is the standard biofilm growth protocol for the validation of US Environmental Protection Agency biofilm label claims. However, no studies have determined the effect of coupon orientation within the reactor on biofilm growth. If positional effects have a statistically significant impact on biofilm density, they should be accounted for in the experimental design. Here, we isolate and quantify biofilms from each possible coupon surface in the reactor to quantitatively determine the positional effects in the CDC Biofilm Reactor. The results showed no statistically significant differences in viable cell density across different orientations and vertical positions in the reactor. Pseudomonas aeruginosa log densities were statistically equivalent among all coupon heights and orientations. While the Staphylococcus aureus cell growth showed no statistically significant differences, the densities were not statistically equivalent among all coupon heights and orientations due to the variability in the data. Structural differences were observed between biofilms on the high-shear baffle side of the reactor compared to the lower shear glass side of the reactor. Further studies are required to determine whether biofilm susceptibility to antimicrobials differs based on structural differences attributed to orientation.
美国疾病控制与预防中心（CDC）的生物膜反应器方法是验证美国环保署生物膜标签声明的标准生物膜生长方案。然而，尚未有研究确定反应器内生物膜生长过程中试片方向的影响。如果位置效应对生物膜密度有统计学显著影响，则应在实验设计中加以考虑。本研究从反应器中每个可能的试片表面分离和量化生物膜，以定量确定 CDC 生物膜反应器中的位置效应。结果表明，不同方向和反应器内垂直位置的生物膜活菌密度没有统计学显著差异。铜绿假单胞菌的对数密度在所有试片高度和方向上均具有统计学等效性。虽然金黄色葡萄球菌的细胞生长没有统计学显著差异，但由于数据的变异性，所有试片高度和方向上的密度并不具有统计学等效性。与反应器较低剪切力的玻璃侧相比，在反应器高剪切挡板侧的生物膜观察到结构差异。需要进一步研究，以确定是否由于方向导致的结构差异会影响生物膜对抗微生物药物的敏感性。
