Seafood Microbiology and Technology Section, Marine Research Institute, Eduardo Cabello 6, Vigo, Pontevedra, Spain.
Curr Microbiol. 2013 Feb;66(2):110-21. doi: 10.1007/s00284-012-0247-8. Epub 2012 Oct 14.
Staphylococcus aureus is a pathogenic bacterium capable of developing biofilms on food-processing surfaces, a pathway leading to cross contamination of foods. The purpose of this study was to investigate the influence of environmental stress factors found during seafood production on the adhesion and biofilm-forming properties of S. aureus. Adhesion and biofilm assays were performed on 26 S. aureus isolated from seafood and two S. aureus reference strains (ATCC 6538 and ATCC 43300). Cell surface properties were evaluated by affinity measurements to solvents in a partitioning test, while adhesion and biofilm assays were performed in polystyrene microplates under different stress conditions of temperature, osmolarity, and nutrient content. The expression of genes implicated in the regulation of biofilm formation (icaA, rbf and σ( B )) was analyzed by reverse transcription and quantitative real time PCR. In general, S. aureus isolates showed moderate hydrophobic properties and a marked Lewis-base character. Initial adhesion to polystyrene was positively correlated with the ionic strength of the growth medium. Most of the strains had a higher biofilm production at 37 °C than at 25 °C, promoted by the addition of glucose, whereas NaCl and MgCl(2) had a lower impact markedly affected by incubation temperatures. Principal Component Analysis revealed a considerable variability in adhesion and biofilm-forming properties between S. aureus isolates. Transcriptional analysis also indicated variations in gene expression between three characteristic isolates under different environmental conditions. These results suggested that the prevalence of S. aureus strains on food-processing surfaces is above all conditioned by the ability to adapt to the environmental stress conditions present during food production. These findings are relevant for food safety and may be of importance when choosing the safest environmental conditions and material during processing, packaging, and storage of seafood products.
金黄色葡萄球菌是一种能够在食品加工表面形成生物膜的致病菌，这是导致食品交叉污染的途径。本研究旨在研究在海产品生产过程中发现的环境应激因素对金黄色葡萄球菌粘附和生物膜形成特性的影响。在 26 株从海产品中分离的金黄色葡萄球菌和两株金黄色葡萄球菌参考株（ATCC 6538 和 ATCC 43300）上进行了粘附和生物膜测定。通过分配试验中的溶剂亲和测量评估细胞表面性质，而在不同的温度、渗透压和营养含量的应激条件下，在聚苯乙烯微板上进行粘附和生物膜测定。通过反转录和定量实时 PCR 分析了与生物膜形成调节相关的基因（icaA、rbf 和 σ( B )）的表达。一般来说，金黄色葡萄球菌分离株表现出中等的疏水性和明显的路易斯碱性质。初始对聚苯乙烯的粘附与生长培养基的离子强度呈正相关。大多数菌株在 37°C 下比在 25°C 下产生更高的生物膜，这是由于添加葡萄糖促进的，而 NaCl 和 MgCl(2) 的影响较小，明显受到孵育温度的影响。主成分分析显示金黄色葡萄球菌分离株之间的粘附和生物膜形成特性存在相当大的可变性。转录分析还表明，在不同的环境条件下，三个特征分离株的基因表达存在差异。这些结果表明，金黄色葡萄球菌菌株在食品加工表面的流行主要取决于其适应食品生产过程中存在的环境应激条件的能力。这些发现与食品安全有关，在选择海产品加工、包装和储存过程中最安全的环境条件和材料时可能很重要。
