Cook Kimberly L, Givan Ethan C, Mayton Holly M, Parekh Rohan R, Taylor Ritchie, Walker Sharon L
USDA-ARS, Food Animal Environmental Systems Research Unit, Bowling Green, KY, USA.
Western Kentucky University, Department of Public Health, Bowling Green, KY, USA.
Int J Food Microbiol. 2017 Dec 4;262:80-88. doi: 10.1016/j.ijfoodmicro.2017.09.017. Epub 2017 Sep 27.
Despite continuing efforts to reduce foodborne pathogen contamination of fresh produce, significant outbreaks continue to occur. Identification of appropriate surrogates for foodborne pathogens facilitates relevant research to identify reservoirs and amplifiers of these contaminants in production and processing environments. Therefore, the objective of this study was to identify environmental Escherichia coli isolates from manures (poultry, swine and dairy) and surface water sources with properties similar to those of the produce associated foodborne pathogens E. coli O157:H7 and Salmonella enterica serotype Typhimurium. The most similar environmental E. coli isolates were from poultry (n=3) and surface water (n=1) sources. The best environmental E. coli surrogates had cell surface characteristics (zeta potential, hydrophobicity and exopolysaccharide composition) that were similar (i.e., within 15%) to those of S. Typhimurium and/or formed biofilms more often when grown in low nutrient media prepared from lettuce lysates (24%) than when grown on high nutrient broth (7%). The rate of attachment of environmental isolates to lettuce leaves was also similar to that of S. Typhimurium. In contrast, E. coli O157:H7, a commonly used E. coli quality control strain and swine isolates behaved similarly; all were in the lowest 10% of isolates for biofilm formation and leaf attachment. These data suggest that the environment may provide a valuable resource for selection of surrogates for foodborne pathogens.
尽管人们不断努力减少新鲜农产品中食源性病原体的污染，但重大疫情仍不断发生。确定食源性病原体的合适替代物有助于开展相关研究，以确定这些污染物在生产和加工环境中的储存库和扩增源。因此，本研究的目的是从粪便（家禽、猪和奶牛）和地表水源中鉴定出具有与农产品相关的食源性病原体大肠杆菌O157:H7和鼠伤寒沙门氏菌相似特性的环境大肠杆菌分离株。最相似的环境大肠杆菌分离株来自家禽（n = 3）和地表水源（n = 1）。最佳的环境大肠杆菌替代物具有与鼠伤寒沙门氏菌相似（即相差15%以内）的细胞表面特征（ζ电位、疏水性和胞外多糖组成），并且在由生菜裂解物制备的低营养培养基中生长时（24%）比在高营养肉汤中生长时（7%）更常形成生物膜。环境分离株在生菜叶上的附着率也与鼠伤寒沙门氏菌相似。相比之下，常用的大肠杆菌质量控制菌株大肠杆菌O157:H7和猪分离株表现相似；在生物膜形成和叶片附着方面，它们均处于分离株的最低10%。这些数据表明，环境可能为选择食源性病原体的替代物提供宝贵资源。
