牛源性停乳链球菌最佳培养基的筛选及影响因素研究

Screening on the culture medium for Streptococcus dysgalactiae isolated from bovine and its influencing factors

为了提高奶牛乳房炎多联苗的免疫效果,对停乳链球菌进行了最佳培养基的筛选及生长过程中影响因素的研究。结果表明,停乳链球菌在改良肉汤中生长缓慢,不适宜其生长,但在优化培养基和THB培养基中长势良好,尤其是在优化培养基中,停乳链球菌生长延迟期大大缩短,培养4 h即进入对数生长期,约12 h达到生长高峰期,生长周期比改良肉汤缩短近约50%,比THB缩短约2 h,且生长高峰期的细菌数量比THB和改良肉汤亦明显提高。培养过程中影响因素试验结果表明,溶氧量对停乳链球菌生长无影响;在优化培养基中,葡萄糖较适宜的浓度为10 g/L;在对数生长期内补加NaOH调节pH值,能明显提高细菌的产量,并能延长其对数生长期。

The aim was to screen the optimum culture medium for bovine source Streptococcus dysgalaetiae, arid to study the influeneing factors in its growing course, so to upgrade the immune effect of multiple vaccines for cow mastitis. It was shown that Streptococcus dysgalactiae proliferated tardily in the improved broth, but grew well in the optimized medium and THB medium, especially in the optimized medium, the growth-delay phase for Streptococcus dysgalactiae was shorten sharply, logarithmic growth phase started only after 4 hours, then reached its growth peak after about 12h. The growth cycle couhl be shorten for about half time than in the improved broth and 2 h than in the THB medium, and the amount of Streptococcus dysgalactiae in the growth peak increased clearly than in the THB medium and improved broth. The dissolved oxygen capacity had no effects on the growth of Streptococcus dysgalactiae, the optimized medium which contained 10 g/L glucose was feasible, the addition of NaOH to adjust the pH value in the logarithm growth phase could obviously increase the amount of Streptococcus dysgalactiae and extend the duration of the logarithm growth phase.