探討食品病原菌和分離自截切小黃瓜之菌株共培養後生物膜的形成

Abstract

新鮮截切小黃瓜與多次食品安全事件有關，而截切蔬果很容易遭受E. coli或L. innocua等食品病原菌所污染。生物膜的形成是細菌的在環境中最主要的生存形式，其中細菌會附著在生物或非生物表面並分泌胞外聚合物物質以形成保護基質。根據我們實驗室先前的研究表明，從新鮮截切小黃瓜中所分離的E. mori FS08和Pantoea sp. 能夠形成生物膜。另外也有研究表明，生物膜的形成可以促進微生物菌群在環境中的生存和適應性反應。因此，探討E. coli或L. innocua與E. mori FS08或Pantoea sp. 的共培養生物膜的形成是有必要的。從研究結果顯示，當E. coli與Pantoea sp. 和E. mori FS08共培養時，生物膜形成是減少的。相反的，L. innocua與Pantoea sp. 和E. mori FS08共培養時，與Pantoea sp. 單獨培養相比沒有顯著性差異。雖然生物膜的形成與單獨培養不同，但有些細菌的生物膜內之菌數濃度沒有顯著變化。E. mori FS08抑制了E. coli的生長，並減少了L. innocua在生物膜中的生長。然而，這些共培養菌株之間的相互作用尚不清楚。瞭解生物膜內菌株的相互作用可以通過共聚焦顯微鏡（Confocal laser scanning microscopy, CLSM）來解釋。共聚焦顯微鏡的結果顯示不同的生物膜結構，包括蜂窩狀結構和緊密排列的菌落。這些發現將提供有關於生物膜形成所潛在的風險，並強調了探討食品病原菌與細菌在共培養生物膜中的相互作用之重要性。

Fresh-cut cucumbers have been linked to multiple outbreaks of foodborne illnesses, potentially contaminated by pathogenic bacteria, such as Escherichia coli or Listeria. The formation of biofilms is a critical survival strategy for bacteria, in which they attach to a biotic or abiotic surface and secrete extracellular polymeric substances to form a protective matrix. Our previous research has demonstrated the ability of plant-pathogenic strains, Enterobacter mori FS08 and Pantoea sp. isolated from fresh-cut cucumbers, to form biofilms. Studies have indicated that biofilm cultivation can facilitate the coexistence and adaptive responses of bacterial communities. Therefore, it is imperative to explore biofilm formation through the co-culture of foodborne pathogens, including E. coli or Listeria innocua with E. mori FS08 or Pantoea sp. The results reveal that biofilm formation decreases when E. coli is co-cultured with Pantoea sp. and E. mori FS08. Conversely, the co-culture of L. innocua with Pantoea sp. and E. mori FS08 exhibits no change compared to the Pantoea sp. mono-culture group. Although biofilm formations differ from mono-culture, some bacteria demonstrate no significant variations in biofilm cell concentration, except E. mori FS08. Noteworthily, E. mori FS08 inhibits the growth of E. coli and diminishes the growth of L. innocua within the biofilm. However, the interaction between the co-culture bacteria remains unclear. Further analysis of the biofilm interaction may be explained by using confocal laser scanning microscopy (CLSM). The CLSM results show different biofilm structures, honey-comb-like structures, and dense clusters. These findings will provide insights into the potential risks associated with biofilm formation and highlight the importance of understanding the interactions between foodborne pathogens and bacteria in the co-culture biofilm.