TI Food and Nutrition, PO Box 557, 6700 AN Wageningen, The Netherlands.
Int J Food Microbiol. 2013 Aug 1;165(3):259-64. doi: 10.1016/j.ijfoodmicro.2013.05.025. Epub 2013 Jun 5.
The foodborne pathogen Listeria monocytogenes has the ability to produce biofilms in food-processing environments and then contaminate food products, which is a major concern for food safety. The biofilm forming behavior of 143 L. monocytogenes strains was determined in four different media that were rich, moderate or poor in nutrients at 12°C, 20°C, 30°C and 37°C. The biofilm formation was mostly influenced by temperature, resulting in decreased biofilm formation with decreasing temperature. Biofilm formation was enhanced in nutrient-poor medium rather than in nutrient-rich medium, and especially in nutrient-poor medium significantly enhanced biofilm production was observed early in biofilm maturation underlining the effect of medium on biofilm formation rate. Also serotype had a significant effect on biofilm formation and was influenced by medium used because strains from both serotype 1/2b and 1/2a formed more biofilm than serotype 4b strains in nutrient-rich medium at 20°C, 30°C and 37°C, whereas in nutrient-poor medium the biofilm production levels of serotype 1/2a and 4b strains were rather similar and lower than serotype 1/2b strains. The strains used originated from various origins, including dairy, meat, industrial environment, human and animal, and the level of biofilm formation was not significantly affected by the origin of isolation, irrespective of medium used and temperature tested. A linear model was used to correlate crystal violet staining of biofilm production to the number of viable cells within the biofilm. This showed that crystal violet staining was poorly correlated to the number of viable cells in nutrient-poor medium, and LIVE/DEAD staining and DNase I treatment revealed that this could be attributed to the presence of non-viable cells and extracellular DNA in the biofilm matrix. The significant impact of intrinsic and extrinsic factors on biofilm production of L. monocytogenes underlined that niche-specific features determine the levels of biofilm produced, and insights in biofilm formation characteristics will allow us to further optimize strategies to control the biofilm formation of L. monocytogenes.
食源性病原体单核细胞增生李斯特菌能够在食品加工环境中形成生物膜，然后污染食品产品，这是食品安全的主要关注点。在 12°C、20°C、30°C 和 37°C 下，在四种不同的营养丰富、中等或贫营养培养基中，测定了 143 株单核细胞增生李斯特菌菌株的生物膜形成行为。生物膜形成主要受温度影响，随着温度降低，生物膜形成减少。贫营养培养基中生物膜形成增强，而不是在营养丰富的培养基中，特别是在生物膜成熟早期的贫营养培养基中，生物膜产量显著增强，突出了培养基对生物膜形成速率的影响。血清型也对生物膜形成有显著影响，并受所用培养基的影响，因为在 20°C、30°C 和 37°C 的营养丰富培养基中，来自血清型 1/2b 和 1/2a 的菌株比血清型 4b 菌株形成更多的生物膜，而在贫营养培养基中，血清型 1/2a 和 4b 菌株的生物膜产量水平相当相似，且低于血清型 1/2b 菌株。所用菌株来自各种来源，包括乳制品、肉类、工业环境、人类和动物，并且生物膜形成水平不受分离来源的显著影响，无论使用何种培养基和测试温度。线性模型用于将生物膜产量的结晶紫染色与生物膜内活细胞的数量相关联。这表明结晶紫染色与贫营养培养基中活细胞的数量相关性较差，而 LIVE/DEAD 染色和 DNase I 处理表明，这可能归因于生物膜基质中存在非活细胞和细胞外 DNA。内在和外在因素对单核细胞增生李斯特菌生物膜形成的显著影响强调了特定生态位特征决定了生物膜的产生水平，对生物膜形成特征的深入了解将使我们能够进一步优化控制单核细胞增生李斯特菌生物膜形成的策略。
