食品中金黄色葡萄球菌生物被膜形成基因分析及影响因素研究

分析金黄色葡萄球菌食品分离菌株生物被膜形成相关基因,研究茶多酚和乳酸链球菌素(Nisin)对不同菌株生长及生物被膜形成的影响。以实验室保存的16株金黄色葡萄球菌食品分离菌株为研究对象,采用聚合酶链式反应(PCR)检测14种生物被膜形成相关基因;通过微孔板法研究不同浓度茶多酚和Nisin对不同菌株生长的抑制作用,确定最小抑菌浓度(MIC);在此基础上进一步研究茶多酚和Nisin对生物被膜形成能力影响。结果表明:14种生物被膜形成相关基因中有10种被检出,其中cna、ebp S、fib和ica AD基因检出率为100%,sas C为87.5%、fnb A为68.75%、sas G为68.75%、clf B为68.75%、eno为62.5%,ica BC为56.25%;16株菌株中均不携带bbp、bap、clf A和fnb B基因。16株菌株均能形成生物被膜,但形成能力有差异,其中F23、F44、F58、F64、F71、F86、F107和F109等8株菌株为被膜强形成菌株,F7、F19、F40、F46、F60、F99、F101、F106等8株菌株为被膜弱形成菌株。茶多酚和Nisin对16株金黄色葡萄球菌食品分离菌株的MIC范围分别为0.1~0.2 g/L和0.125~1 g/L,茶多酚和Nisin在1/2MIC和1/4MIC浓度下对生物被膜形成抑制作用明显(p<0.05),且茶多酚抑制效果强于Nisin。本研究结果为食品中金黄色葡萄球菌生物被膜形成控制具有参考意义。 

Analysis of biofilm formation related genes and its influence factors for Staphylococcus aures food isolates

The present study investigated 14 biofilm formation related genes involved in Staphylococcus aureus food isolates and further evaluated the effect of tea polyphenols and Nisin on the growth and biofilm formation of these strains.All the 16 S.aureus strains were collected from food source. 14 adhesin genes were detected by polymerase chain reaction ( PCR) using specific primer.The antibacterial activity and minimal inhibitory concentration ( MIC) of tea polyphenols and Nisin were tested using the microtiter-plate method.The effects of tea polyphenols and Nisin on the biofilm formation were also executed using microtiterplate method.The results showed that 10/14 adhesin genes were detected.The detection rates of cna, ebp S, fib and ica AD genes were 100%, followed by sas C ( 87.5%) , fnb A ( 68.75%) , sas G ( 68.75%) , clf B ( 68.75%) , eno ( 62.5%) and ica BC ( 56.25%) , respectively.However, the bbp, bap, clf A and fnb B genes were not present in any strains detected. All the tested strains were found to have the ability to form and accumulate biofilm. F23、F44、F58、F64、F71、F86、F107 and F109 were strong biofilm producers, and F7、F19、F40、F46、F60、F99、F101、F106 were weak biofilm producers. The MIC values of tea polyphenols and Nisin to 16 strains ranged from 0.1 to 0.2 g/L and 0.125 to 1 g/L, respectively.1/2 MIC and 1/4MIC of tea polyphenols and Nisin had very significant inhibitory effect on the biofilm formation to the tested strains ( p < 0.05) , and tea polyphenols had better antibacterial activity to S.aureus strains than Nisin.The results of this study would play a valued role to the S.aureus food isolates biofilm formation and control strategy.