Abstract: Objective To identify the role of spd1672 gene in Streptococcus pneumoniae cell wall polysaccharide synthesis and proliferation. Methods spd1672-deletion strains were generated by the method of alternative inactivation in Streptococcus pneumoniae D39 and R6 strains. The thickness of capsular polysaccharide was detected by electron microscope，and teichoic acid was detected by Western blot. Furthermore，the growth of wild strains and spd1672-deletion strains in vitro were observed by absorption spectrophotometry. Results No difference was found in the thickness of capsule between wild strains and spd1672-deletion strains. However, the teichoic acid synthesis was significantly reduced in spd1672-deletion strains than that in wild strains. In addition, compared with wild strains, spd1672-deletion strains grow more slowly. Conclusion SPD1672 is a new virulence factor of Streptococcus pneumoniae, which may participate in the regulation of teichoic acid synthesis of Streptococcus pneumoniae and affect its growth in vivo.

Key words: streptococcus pneumoniae, O-Antigen polymerase, teichoic acid