Fang W, Shi M, Huang L, Chen J, Wang Y
Department of Veterinary Medicine, College of Animal Sciences, Zhejiang Agricultural University, Hangzhou, China.
Vet Res. 1996;27(1):3-12.
The antagonistic effect of lactic acid bacteria (LAB, including Lactobacillus acidophilus, L. bulgaricus, L. casei and Streptococcus thermophilus) on Staphylococcus aureus and Escherichia coli was evaluated on MRS agar with the deferred and cross-streaking techniques, and in milk with the plate counting method. All LAB were repressive to S aureus and E coli on the agar medium. However, their suppressive activity was significantly reduced when the agar medium was buffered to pH 7.2. In normal milk, L acidophilus strains A and B, S thermophilus and its combinations with L acidophilus A and L bulgaricus 6032 were inhibitory to S aureus, while in mastitic milk, only S thermophilus and its combinations showed inhibition. L acidophilus A and L bulgaricus 34104 were repressive to E coli growth in normal milk. S thermophilus and its combinations were inhibitory to E coli in both the normal and mastitic milk samples. These results indicate that the antagonistic activity of LAB on pathogenic bacteria varied with the type of media in which the tests were done, and that testing of in vitro antagonism in milk would be more informative than that in artificial media for in vivo tests concerning the possible roles of competitive microbiological ecology in mastitis control.
采用延迟划线和交叉划线技术，在MRS琼脂培养基上，并用平板计数法在牛奶中评估了乳酸菌（LAB，包括嗜酸乳杆菌、保加利亚乳杆菌、干酪乳杆菌和嗜热链球菌）对金黄色葡萄球菌和大肠杆菌的拮抗作用。所有乳酸菌在琼脂培养基上均对金黄色葡萄球菌和大肠杆菌有抑制作用。然而，当琼脂培养基缓冲至pH 7.2时，它们的抑制活性显著降低。在正常牛奶中，嗜酸乳杆菌菌株A和B、嗜热链球菌及其与嗜酸乳杆菌A和保加利亚乳杆菌6032的组合对金黄色葡萄球菌有抑制作用，而在患乳腺炎的牛奶中，只有嗜热链球菌及其组合显示出抑制作用。嗜酸乳杆菌A和保加利亚乳杆菌34104对正常牛奶中大肠杆菌的生长有抑制作用。嗜热链球菌及其组合在正常和患乳腺炎的牛奶样本中均对大肠杆菌有抑制作用。这些结果表明，乳酸菌对病原菌的拮抗活性随测试所用培养基类型的不同而变化，并且对于乳腺炎控制中竞争性微生物生态学可能发挥的作用而言，在牛奶中进行体外拮抗测试比在人工培养基中进行测试对于体内测试更具参考价值。
