不同温度单增李斯特菌和金黄色葡萄球菌混合培养生物被膜的形成

Biofilm Formation by Mixed Culture of Listeria monocytogenes and Staphylococcus aureus at Different Temperatures

自然条件下,食品通常会污染多种食源性病原菌,形成由不同病原菌组成的混合菌种生物被膜,从而危及食品安全。因此,采用结晶紫法、MTT法、荧光显微观察、扫描电镜和激光共聚焦显微镜研究了不同温度(4,25,37℃)单增李斯特菌和金黄色葡萄球菌混合培养生物被膜形成情况。结果表明,4℃培养时,单增李斯特菌和金黄色葡萄球菌生长缓慢,混合培养培养时,基本没有生物被膜形成,单增李斯特菌是优势菌;25℃培养时,单增李斯特菌和金黄色葡萄球菌生长良好,混合培养时,小部分菌体聚集成团,堆叠在一起形成生物被膜;37℃培养时,单增李斯特菌和金黄色葡萄球菌生长旺盛,混合培养时,大部分菌体聚集成团,堆叠在一起,连成一片形成生物被膜。25℃和37℃混合培养,生物被膜中金黄色葡萄球菌远多于单增李斯特菌。研究为评估食品生产环境中单增李斯特菌和金黄色葡萄球菌的混合菌种生物被膜污染风险和制定高效清除方案提供依据。

Food is usually contaminated by a variety of food-borne pathogens under natural conditions,forming a mixed-species biofilm composed of different pathogenic bacteria,which endangers food safety.Therefore,the formation of the mixed culture biofilms of Listeria monocytogenes and Staphylococcus aureus at different temperatures(4,25,37℃)were investigated using crystal violet staining,MTT method,fluorescence microscopy,scanning electron microscopy,and laser confocal microscopy.The results showed that L.monocytogenes and S.aureus grew slowly at 4℃,and there was basically no biofilm formation at mixed culture,and L.monocytogenes was the dominant bacterium.At 25℃,L.monocytogenes and S.aureus grew well,and a small portion of the bacterium gathered into clusters and stacked together to form biofilm at mixed culture.At 37℃,L.monocytogenes and S.aureus grew vigorously,and most of the bacterium gathered into clusters and stacked together to form biofilm at mixed culture.S.aureus was much more abundant than L.monocytogenes in the biofilm when mixed cultured at 25℃and 37℃.This study provided a reference for assessing the risk of biofilm contamination of mixed strains of L.monocytogenes and S.aureus in food production environments and for developing effective removal strategies.