金黄色葡萄球菌拮抗细菌的分离鉴定及拮抗活性分析

Isolation and identification of antagonistic bacteria and analysis of antagonistic activity against Staphylococcus aureus

该研究以自然发酵芥菜为原材料,通过分离筛选,得到9株对金黄色葡萄球菌PJ-1有拮抗活性的细菌,分别用点接法、牛津杯法筛选出拮抗活性较好的细菌,通过形态学观察和分子生物学鉴定确定细菌种类,用乙酸乙酯对拮抗细菌的发酵产物进行萃取,并用气相色谱-质谱(GC-MS)进行成分分析。结果表明,两种方法筛选出3株对金黄色葡萄球菌PJ-1拮抗作用较好的菌株SC-3、SC-6、SC-9,鉴定结果分别为贝莱斯芽孢杆菌(Bacillus velezensis)、莫海威芽孢杆菌(Bacillus mojavensis)、解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。菌株SC-3乙酸乙酯粗提物(AE)对菌株PJ-1有较好拮抗作用,其抑菌率达75.04%。通过GC-MS对菌株SC-3的乙酸乙酯粗提物进行成分分析,结果表明,主要物质为10-羟基-2-癸烯酸(41.99%)、1,4-二氮杂2,5-二氧杂-3-异丁基双环[4.3.0]壬烷(8.80%)、3-甲基二氧哌嗪(8.26%)、L-亮氨酸(5.83%)等,其可运用于食源性金黄色葡萄球菌的防治。

In this study,9 strains of bacteria with antagonistic activity against Staphylococcus aureus PJ-1 were obtained by isolation and screening from natural fermented mustard.The strains with good antagonistic activity were selected by point-joint method and Oxford cup method respectively,and the strains were identified by morphological observation and biology identification.The fermentation products of the screened strains were extracted with ethyl acetate for composition analysis by GC-MS.The results showed that three strains SC-3,SC-6,and SC-9 with better antagonistic effects on S.aureus PJ-1 were screened using two methods,and they were identified as Bacillus velezensis,Bacillus mojavensis,and Bacillus amyloliquefaciens,respectively.The crude extract of strain SC-3 from ethyl acetate had a good antagonistic effect on strain PJ-1,with an antibacterial rate of 75.04%.The composition of ethyl acetate extract of strain SC-3 was analyzed by GC-MS,it was found that the main substances were 10-hydroxy-2-decenoic acid(41.99%),1,4-diazazine,5-dioxa-3-isobutyldicycloxylic acid[4.3.0]nonane(8.80%),3-methyldioxy-piperazine(8.26%),L-leucine(5.83%),etc.It is suggested that the components of B.velezensis may be used in the control of foodborne S.aureus.