a Department of Chemical and Biochemical Engineering , University of Iowa , Iowa City , IA , USA.
b Department of Chemical Engineering , University of Technology , Baghdad , Iraq.
Int J Hyperthermia. 2018 Mar;34(2):168-176. doi: 10.1080/02656736.2017.1347964.
Biofilms on implanted medical devices cause thousands of patients each year to undergo multiple surgeries to remove and replace the implant, driving billions of dollars in increased health care costs due to the lack of viable treatment options for in situ biofilm eradication. Remotely activated localised heating is under investigation to mitigate these biofilms; however, little is known about the temperatures required to kill the biofilms. To better understand the required parameters this study investigated the thermal susceptibility of biofilms as a function of their fluidic and chemical environment during growth, as well as their propensity for regrowth following thermal shock. Pseudomonas aeruginosa biofilms were cultured in shaker plate fluidic conditions in four different growth media, then thermally shocked at various temperatures and exposure times. Biofilms were re-incubated to determine their regrowth potential following thermal shocks of various intensities. Results indicate that growth media has little impact on thermal susceptibility, while fluidic conditions strongly influence susceptibility to modest thermal shocks. This effect disappears, however, with increasingly aggressive shocks, reducing biofilm populations by up to 5 orders of magnitude. Regrowth studies indicate a critical post-shock bacterial loading (∼10 CFU/cm) below which the biofilms were no longer viable, while biofilms above that loading slowly regrew to their previous population density.
植入式医疗设备上的生物膜每年导致数千名患者接受多次手术以移除和更换植入物，由于缺乏可行的原位生物膜清除治疗选择，导致医疗保健成本增加数十亿美元。正在研究远程激活局部加热以减轻这些生物膜；然而，对于杀死生物膜所需的温度知之甚少。为了更好地了解所需参数，本研究调查了生物膜在其生长过程中的流体和化学环境以及热冲击后再生的倾向作为功能的热敏感性。铜绿假单胞菌生物膜在四个不同的生长培养基中在摇板流体条件下培养，然后在不同温度和暴露时间下进行热冲击。生物膜重新孵育以确定它们在各种强度的热冲击后的再生潜力。结果表明，生长培养基对热敏感性影响不大，而流体条件对适度热冲击的敏感性影响很大。然而，随着冲击越来越剧烈，这种影响消失了，生物膜的数量减少了多达 5 个数量级。再生研究表明，在细菌载量（约 10 CFU/cm）以下，生物膜不再存活，而载量高于该水平的生物膜则缓慢地再生到以前的种群密度。
