PDF(Sci-hub)
Abstract：
Biofilms are formed by microorganisms protected by a self-produced matrix, most often attached to a surface. In the food processing environments biofilms endanger the product safety by the transmission of spoilage and pathogenic bacteria. In this study, we characterised the biofilm formation of the following eleven strains isolated from biofilms in a meat-processing environment: Acinetobacter harbinensis BF1, Arthrobacter sp. BF1, Brochothrix thermosphacta BF1, Carnobacterium maltaromaticum BF1, Kocuria salsicia BF1, Lactococcus piscium BF1, Microbacterium sp. BF1, Pseudomonas fragi BF1, Psychrobacter sp. BF1, Rhodococcus erythropolis BF1, Stenotrophomonas sp. BF1. We applied whole- genome sequencing and subsequent genome analysis to elucidate genetic features associated with the biofilm lifestyle. We furthermore determined the motility and studied biofilm formation on stainless steel using a static mono-species biofilm model mimicking the meat processing environment. The biomass and the EPS components carbohydrates, proteins and extracellular DNA (eDNA) of the biofilms were investigated after seven days at 10 °C. Whole-genome analysis of the isolates revealed that all strains except the Kocuria salsicia BF1 isolate, harboured biofilm associated genes, including genes for matrix production and motility. Genes involved in cellulose metabolism (present in 82% of the eleven strains) and twitching motility (present in 45%) were most frequently found. The capacity for twitching was confirmed using plate assays for all strains except Lactococcus piscium BF1, which showed the lowest motility behaviour. Differences in biofilm forming abilities could be demonstrated. The bacterial load ranged from 5.4 log CFU/cm2 (Psychrobacter sp. isolate) to 8.7 log CFU/cm2 (Microbacterium sp. isolate). The amount of the matrix components varied between isolates. In the biofilm of six strains we detected all three matrix components at different levels (carbohydrates, proteins and eDNA), in two only carbohydrates and eDNA, and in three only carbohydrates. Carbohydrates were detected in biofilms of all strains ranging from 0.5 to 4.3 μg glucose equivalents/cm2. Overall, the Microbacterium sp. strain showed the highest biofilm forming ability with high bacterial load (8.7 log CFU/cm2) and high amounts of carbohydrates (2.2 μg glucose equivalents/cm2), proteins (present in all experiments) and eDNA (549 ng/cm2). In contrast, Brochothrix thermosphacta was a weak biofilm former, showing low bacterial load and low levels of carbohydrates in the matrix (6.2 log CFU/cm2 and 0.5 μg glucose equivalents/cm2). This study contributes to our understanding of the biofilm forming ability of bacteria highly abundant in the meat processing environment, which is crucial to develop strategies to prevent and reduce biofilm formation in the food producing environment.
摘要：
生物膜是由自产基质保护的微生物形成的，通常附着在表面上。在食品加工环境中，生物膜通过腐败和致病菌的传播危害产品安全。在这项研究中,我们表征了在肉类加工环境中从生物膜中分离出的以下11种菌株的生物膜形成：哈氏不动杆菌BF1，节杆菌属。BF1，嗜热菌BF1，伤心菌BF1，科古里亚盐藻BF1，双钙乳球菌BF1，微杆菌属。BF1，假单胞菌BF1，嗜冷杆菌。BF1，红球红球菌BF1，窄食单胞菌属。BF1.我们应用全基因组测序和随后的基因组分析来阐明与生物膜生活方式相关的遗传特征。我们还使用模拟肉类加工环境的静态单物种生物膜模型确定了运动性并研究了不锈钢上的生物膜形成。生物质和EPS成分碳水化合物，在10°C下七天后研究生物膜的蛋白质和细胞外DNA(eDNA)。分离株的全基因组分析显示，除了KocuriasalsiciaBF1分离株，隐藏生物膜相关基因，包括基质生产和运动的基因。最常见的是涉及纤维素代谢的基因（在11个菌株中的82％中存在）和抽搐运动（在45％中存在）。抽搐的能力是使用平板测定法对所有菌株进行确认的，但双钙乳球菌BF1除外，后者表现出最低的运动行为。可以证明生物膜形成能力的差异。细菌载量范围为5.4logCFU/cm2（嗜冷细菌。分离）至8.7logCFU/cm2（微细菌。隔离)。基质组分的量在分离株之间变化。在六个菌株的生物膜中，我们检测到了不同水平的所有三种基质成分（碳水化合物，蛋白质和eDNA），只有两种碳水化合物和eDNA，只有三种碳水化合物。在0.5至4.3μg葡萄糖当量/cm2的所有菌株的生物膜中检测到碳水化合物。总的来说,微细菌。菌株表现出最高的生物膜形成能力，具有高细菌负荷（8.7logCFU/cm2）和高量的碳水化合物（2.2μg葡萄糖当量/cm2），蛋白质（存在于所有实验中）和eDNA（549ng/cm2）。相比之下,Brochothrix热球是一种弱的生物膜前身，显示低细菌负荷和基质中碳水化合物水平低(6.2logCFU/cm2和0.5μg葡萄糖当量/cm2)。这项研究有助于我们了解肉类加工环境中高度丰富的细菌的生物膜形成能力，这对于制定预防和减少食品生产环境中生物膜形成的策略至关重要。
