目的　研究肺炎球菌多糖结合疫苗中各血清型肺炎球菌在液体培养基中传代培养的稳定性。方法　在液体培养基中对各代次肺炎球菌的培养时长进行对比；对第15代次（P15）与P4（对照组）进行菌种检定与荚膜多糖抗原基因序列分析；将P15菌种按生产工艺进行发酵培养，分析培养情况和荚膜多糖抗原产量及质量，与P4代次对比。结果　在P7—P15中，各代次培养时长相近，且P15菌种检定、抗原基因序列与P4相比无差异，序列相似度为100%；P15菌种发酵培养后，菌体生长、荚膜多糖产量与荚膜多糖相关检定指标与P4无明显差异，且均符合中国药典质量标准。结论　用于生产肺炎球菌多糖结合疫苗的各血清型肺炎球菌在液体环境中传代培养稳定。

Objective　To evaluate the passage stability of pneumococcal subcultures of all serotypes for pneumococcal polysaccharide conjugate vaccine in a liquid medium.Methods　The culture duration of each generation of pneumococcus in a liquid environment was compared. The characterization of bacteria and capsular polysaccharide antigen gene sequences of the 15th generation (P15) and P4 (control group) strain were analyzed. Then, P15 was fermented and purified according to the production process, and the yield and quality of capsular polysaccharide antigen were analyzed by determination methods and compared with P4.Results　In P7-P15, the culture duration of each generation was similar, and there was no difference in strain identification and antigen gene sequence between P15 and P4, with the sequence similarity of 100%. After the fermentation of P15 strains, there was no apparent difference in the growth of cells, the yield of capsular polysaccharides and the related indexes of capsular polysaccharides compared with P4, and the verification indexes were in line with Cinese pharmacopoeia standards.Conclusion　Pneumococcal subcultures of all serotypes for pneumococcal polysaccharide conjugate vaccine have good passage stability in a liquid environment.