难培养微小小单胞菌培养基改良

Culture medium optimization of fastidious Parvimonas micra

摘要:

【目的】改良微小小单胞菌(Parvimonas micra)培养基组分，提高活菌量，探究一套模型化的难培养细菌培养方法。【方法】选取一株微小小单胞菌，对其进行生化分析，初步筛选出可能促进微小小单胞菌生长的底物，对每种底物分别设置3个浓度并采用单因素试验的方法进行验证，对筛选出的增菌效果明显的底物进行浓度优化，得到新的培养基。【结果】单因素试验筛选后得到增菌效果明显的底物为l-丝氨酸、l-苏氨酸、甘氨酰-l-谷氨酰胺。在本优化体系下，培养基中添加4.8 g/L的l-丝氨酸后微小小单胞菌活菌量可达3.6×10⁸ cfu/mL，较胰蛋白胨大豆肉汤(tryptone soya broth, TSB)培养基+胎牛血清(fetal bovine serum, FBS)基础培养基活菌量提高了4.2倍；将改良后的培养基应用于其他微小小单胞菌菌株，培养结果显示改良后的培养基在菌种水平上有良好地促进微小小单胞菌生长的效果。【结论】本研究表明利用生化鉴定板筛选难培养细菌培养基补充剂，是一种快捷、高效的筛选手段，并为难培养细菌的扩大培养提供参考。

Abstract:

[Objective] To improve the culture medium components of Parvimonas micra, increase the number of live cells, and develop a demonstration method for culturing fastidious bacteria. [Methods] Biochemical analysis was conducted on a strain of P. micra to screen the potential substrates that could promote bacterial growth. A single-factor experiment was carried out for each substrate with three concentrations. The substrate with a significant bacterial enrichment effect was further optimized for concentration, and thus a new culture medium was obtained. [Results] The single-factor experiment results showed that the substrates with significant bacterial enrichment effects included l-serine, l-threonine, and glycyl-l-glutamine. In the medium with the addition of 4.8 g/L l-serine, the live cell count of P. micra reached 3.6×10⁸ cfu/mL, representing a 4.2-fold increase compared with that in the basic medium with tryptone soya broth (TSB) and fetal bovine serum (FBS). Furthermore, the improved culture medium was applied to the culture of another P. micra strain, demonstrating a significant growth-promoting effect. [Conclusion] This study proves that using biochemical identification plates to screen medium supplements is a fast and efficient method, providing a reference for the enlargement culture of fastidious bacteria.