Abstract：
The efficacy of a sanitizer in biofilm removal may be influenced by a combination of factors such as sanitizer exposure time and concentration, bacterial species, surface topography, and shear stresses. We employed an inline biofilm reactor to investigate the interactions of these variables on biofilm removal with chlorine. The CDC bioreactor was used to grow E. coli O157:H7 and L. monocytogenes biofilms as a single species or with Ralstonia insidiosa as a dual-species biofilm on stainless steel, PTFE, and EPDM coupons at shear stresses 0.368 and 2.462 N/m2 for 48 hours. Coupons were retrieved from a CDC bioreactor and placed in an inline biofilm reactor and 100, 200, or 500 ppm of chlorine was supplied for 1- and 4 min. Bacterial populations in the biofilms were quantified pre- and posttreatment by plating on selective media. After chlorine treatment, reduction (Log CFU/cm2) in pathogen populations obtained from three replicates was analyzed for statistical significance. A 1-min chlorine treatment (500 ppm), on dual-species E. coli O157:H7 biofilms grown at high shear stress of 2.462 N/m2 resulted in significant E. coli O157:H7 reductions on SS 316L (2.79 log CFU/cm2) and PTFE (1.76 log CFU/cm2). Similar trend was also observed for biofilm removal after a 4-min chlorine treatment. Single species E. coli O157:H7 biofilms exhibited higher resistance to chlorine when biofilms were developed at high shear stress. The effect of chlorine in L. monocytogenes removal from dual-species biofilms was dependent primarily on the shear stress at which they were formed rather than the surface topography of materials. Besides surface topography, shear stresses at which biofilms were formed also influenced the effect of sanitizer. The removal of E. coli O157:H7 biofilms from EPDM material may require critical interventions due to difficulty in removing this pathogen. The inline biofilm reactor is a novel tool to evaluate the efficacy of a sanitizer in bacterial biofilm removal.
摘要：
消毒剂在生物膜去除中的功效可能受到诸如消毒剂暴露时间和浓度等因素的组合的影响。细菌种类,表面形貌和剪切应力。我们使用在线生物膜反应器来研究这些变量对氯去除生物膜的相互作用。CDC生物反应器用于将大肠杆菌O157：H7和单核细胞增生李斯特菌生物膜作为单一物种生长，或将里氏菌作为不锈钢上的双物种生物膜生长，PTFE,和EPDM试样在剪切应力0.368和2.462N/m2下48小时。从CDC生物反应器中回收样品并将其置于在线生物膜反应器中，并在1和4分钟内提供100、200或500ppm的氯。通过在选择性培养基上铺板在处理前和后处理中定量生物膜中的细菌群体。氯处理后，分析从三个重复获得的病原体群体中的减少(LogCFU/cm2)的统计学显著性。1分钟氯气处理（500ppm），在2.462N/m2的高剪切应力下生长的双物种大肠杆菌O157:H7生物膜上导致SS316L(2.79logCFU/cm2)和PTFE(1.76logCFU/cm2)上的大肠杆菌O157:H7显著减少。在4分钟的氯处理之后,对于生物膜去除也观察到类似的趋势。当生物膜在高剪切应力下发展时,单一物种大肠杆菌O157:H7生物膜表现出较高的氯抗性。氯在从双物种生物膜中去除单核细胞增生李斯特菌中的作用主要取决于它们形成的剪切应力，而不是材料的表面形貌。除了表面形貌，形成生物膜的剪切应力也影响消毒剂的作用。由于难以去除这种病原体,从EPDM材料中去除大肠杆菌O157:H7生物膜可能需要关键的干预措施。在线生物膜反应器是评估消毒剂在细菌生物膜去除中的功效的新颖工具。
