Abstract The objectives of this study were: 1) to determine biofilm formation abilities of 11 emetic toxin producing Bacillus cereus strains along with two reference strains ATCC 14579 and KCTC 13153 on stainless steel and plastic coupons; 2) to examine the correlation between biofilm formation ability and genotypic and phenotypic characteristics of four selected strains. Crystal violet assay results indicated that the biofilm formation behavior was highly variable depending on strain and surface. Cell enumeration and scanning electron microscopy (SEM) analysis showed complex cell clusters with extracellular polymeric substances (EPS) for high biofilm forming strains and single layer of cell clusters with few EPS for low biofilm forming strains. Phenotypic characteristics of planktonically grown cells such as hydrophobicity were positively correlated with biofilm formation behavior. However, antibiotic susceptibility of B. cereus strains was not correlated with biofilm formation, although resistance to benzalkonium chloride showed a clear correlation with biofilm formation ability. Expression levels of two genes spo0A and abrB involved in the regulation of cell differentiation and mobility of B. cereus were positively correlated with biofilm formation. Results of this study indicate that multiple factors are involved in biofilm formation by emetic toxin producing B. cereus.

中文翻译：

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蜡样芽孢杆菌催吐毒素生物膜形成的一些基因型和表型特征

摘要 本研究的目的是：1) 确定 11 种产生催吐毒素的蜡状芽孢杆菌菌株以及两种参考菌株 ATCC 14579 和 KCTC 13153 在不锈钢和塑料试样上的生物膜形成能力；2) 检验四个选定菌株的生物膜形成能力与基因型和表型特征之间的相关性。结晶紫测定结果表明，生物膜形成行为因应变和表面而异。细胞计数和扫描电子显微镜 (SEM) 分析显示，对于高生物膜形成菌株，具有胞外聚合物 (EPS) 的复杂细胞簇和对于低生物膜形成菌株具有很少 EPS 的单层细胞簇。浮游生长细胞的表型特征（如疏水性）与生物膜形成行为呈正相关。然而，蜡状芽孢杆菌菌株的抗生素敏感性与生物膜形成无关，尽管对苯扎氯铵的抗性与生物膜形成能力有明显的相关性。参与调节蜡状芽孢杆菌细胞分化和流动性的两个基因 spo0A 和 abrB 的表达水平与生物膜形成呈正相关。这项研究的结果表明，产生催吐毒素的蜡状芽孢杆菌的生物膜形成涉及多种因素。尽管对苯扎氯铵的抗性与生物膜形成能力有明显的相关性。参与调节蜡状芽孢杆菌细胞分化和流动性的两个基因 spo0A 和 abrB 的表达水平与生物膜形成呈正相关。这项研究的结果表明，产生催吐毒素的蜡状芽孢杆菌的生物膜形成涉及多种因素。尽管对苯扎氯铵的抗性与生物膜形成能力有明显的相关性。参与调节蜡状芽孢杆菌细胞分化和流动性的两个基因 spo0A 和 abrB 的表达水平与生物膜形成呈正相关。这项研究的结果表明，产生催吐毒素的蜡状芽孢杆菌的生物膜形成涉及多种因素。