Fernández Ramírez Mónica D, Kostopoulos Ioannis, Smid Eddy J, Nierop Groot Masja N, Abee Tjakko
Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands; Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands.
Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands.
Int J Food Microbiol. 2017 Mar 6;244:43-51. doi: 10.1016/j.ijfoodmicro.2016.12.014. Epub 2016 Dec 29.
Biofilms of Lactobacillus plantarum are a potential source for contamination and recontamination of food products. Although biofilms have been mostly studied using single species or even single strains, it is conceivable that in a range of environmental settings including food processing areas, biofilms are composed of multiple species with each species represented by multiple strains. In this study six spoilage related L. plantarum strains FBR1-FBR6 and the model strain L. plantarum WCFS1 were characterised in single, dual and multiple strain competition models. A quantitative PCR approach was used with added propidium monoazide (PMA) enabling quantification of intact cells in the biofilm, representing the viable cell fraction that determines the food spoilage risk. Our results show that the performance of individual strains in multi-strain cultures generally correlates with their performance in pure culture, and relative strain abundance in multi-strain biofilms positively correlated with the relative strain abundance in suspended (planktonic) cultures. Performance of individual strains in dual-strain biofilms was highly influenced by the presence of the secondary strain, and in most cases no correlation between the relative contributions of viable planktonic cells and viable cells in the biofilm was noted. The total biofilm quantified by CV staining of the dual and multi-strain biofilms formed was mainly correlated to CV values of the dominant strain obtained in single strain studies. However, the combination of strain FBR5 and strain WCFS1 showed significantly higher CV values compared to the individual performances of both strains indicating that total biofilm formation was higher in this specific condition. Notably, L. plantarum FBR5 was able to outgrow all other strains and showed the highest relative abundance in dual and multi-strain biofilms. All the dual and multi-strain biofilms contained a considerable number of viable cells, representing a potential source of contamination.
植物乳杆菌生物膜是食品污染和再污染的潜在来源。尽管生物膜大多是使用单一物种甚至单一菌株进行研究的，但可以想象，在包括食品加工区域在内的一系列环境中，生物膜是由多个物种组成的，每个物种都有多个菌株代表。在本研究中，对六种与腐败相关的植物乳杆菌菌株FBR1 - FBR6和模式菌株植物乳杆菌WCFS1在单菌株、双菌株和多菌株竞争模型中进行了表征。采用定量PCR方法并添加单叠氮化丙锭（PMA），能够对生物膜中的完整细胞进行定量，代表决定食品腐败风险的活细胞部分。我们的结果表明，多菌株培养中单个菌株的表现通常与其在纯培养中的表现相关，多菌株生物膜中相对菌株丰度与悬浮（浮游）培养中的相对菌株丰度呈正相关。双菌株生物膜中单个菌株的表现受到次要菌株存在的高度影响，并且在大多数情况下，未观察到浮游活细胞和生物膜中活细胞的相对贡献之间的相关性。通过对形成的双菌株和多菌株生物膜进行结晶紫（CV）染色定量的总生物膜主要与单菌株研究中获得的优势菌株的CV值相关。然而，菌株FBR5和菌株WCFS1的组合显示出比两种菌株各自的表现显著更高的CV值，表明在这种特定条件下总生物膜形成更高。值得注意的是，植物乳杆菌FBR5能够超过所有其他菌株，并在双菌株和多菌株生物膜中显示出最高的相对丰度。所有双菌株和多菌株生物膜都含有大量活细胞，代表了一个潜在的污染源。
