中国肺炎球菌病疾病负担研究进展

  目的  评估一种转运培养基，脱脂牛奶胰蛋白胨葡萄糖甘油（STGG)对于肺炎链球菌的保存效果。  方法  分别使用STGG和Todd-Hewitt酵母肉汤冻存液（THY，含20 %甘油）将肺炎链球菌稀释相同倍数置于4 ℃保存48 h、1周，置于 – 80 ℃保存1、2个月，涂板培养比较菌落数差异；同时使用STGG培养基制备不同浓度肺炎链球菌菌液分别于 – 20 ℃和 – 80 ℃保存不同时间后涂板培养观察菌落数变化。反复冻融STGG培养基制备的肺炎链球菌菌液后涂板培养观察菌落数变化。  结果  肺炎链球菌在THY冻存液和STGG培养基中4 ℃保存48 h，菌落数量相比于0 h仅变化了1.9 %；保存1周后，THY冻存液中肺炎链球菌菌落数量相比于48 h下降了70.9 %，STGG培养基中下降了48.3 %。不同浓度的肺炎链球菌在STGG培养基中 – 20 ℃及 – 80 ℃保存1个月菌落存活率差异无统计学意义（P > 0.05）， – 80 ℃ 保存2个月存活率明显高于 – 20 ℃（P < 0.05）。 STGG培养基保存液– 80 ℃冻融5次，与第一次冻融相比，菌落数变化在95 %～102 %以内。  结论  相较于THY冻存液，STGG培养基保存效果更好，且 – 80 ℃更利于肺炎链球菌于STGG培养基中的保存。

Streptococcus pneumoniae: transmission,colonization and invasion

  Objective  To evaluate the efficacy of skim milk-tryptone-glucose-glycerin (STGG) – a transport medium for Streptococcus pneumonia (Spn).   Methods   Bacterial suspensions of Spn at three dilution levels were prepared with STGG and Todd-Hewitt yeast broth containing 20% glycerol (THY) cryopreservation solution separately. All the suspensions were stored at 4 °C for 48 hours and one week, at – 80 °C for one month and two months. Plate culture was adopted to assess the difference in colony numbers of preserved Spn with the two medium after repeated freezing and thawing; the variation in colony numbers was also observed for the preserved Spn with STGG stored at – 20 °C and – 80 °C for different period.   Results  The number of Spn colonies changed only by 1.9% after storage with THY cryopreservation medium and STGG at 4 °C for 48 hours compared to that before the storage; while after the storage of one week, the Spn colony number dropped by 70.9% for the preservation with THY cryopreservation medium and 48.3% for with STGG. No significant difference was observed in survival rate of Spn preserved with STGG medium at different dilution levels stored at – 20 °C and – 80 °C for one month (P > 0.05), but the survival rate was significantly higher for the Spn stored at – 80 °C than that at – 20 °C for 2 months (P < 0.05). For the Spn preservation stored at – 80 °C, STGG freezing and thawing 5 times resulted in a change from 95% – 102% in the number of colonies.   Conclusion  Compared with THY cryopreservation solution, STGG medium results in a better efficacy for Streptococcus pneumoniae preservation, especially when stored at a temperature of – 80 °C.