B群链球菌液体显色培养基改良及性能评价

Improvement and Performance Evaluation of Liquid Chromogenic Medium for Group B Streptococcus

目的改进B群链球菌(GBS)液体显色培养基组成,提高GBS液体显色培养基筛选灵敏度。方法选取15株GBS(3株标准菌株,12株临床菌株),9株非GBS的标准菌株,通过单因子优选实验和正交试验分析,选出最优配方。选取GBS 62株,非GBS 20株,分别配制不同浓度检测改良液体培养基的性能。结果在Todd-Hewitt基础肉汤中添加质量浓度为8 g·L^(-1)的庆大霉素、15 g·L^(-1)的萘啶酸、6.5 g·L^(-1)的牛心浸粉、1.25 g·L^(-1)的羟丙基β-环糊精、3.5 g·L^(-1)的盐酸半胱氨酸、1.1 g·L^(-1)的L-鸟氨酸、0.4 g·L^(-1)的鼠李糖、12 mg·L^(-1)的氯化血红素、4 mg·L^(-1)的两性霉素B和体积分数为0.1%的绵羊血清、0.005%的DMF,其中绵羊血清和牛心浸粉、L-鸟氨酸的P值分别为0.013、0.005、0.012;改良液体显色培养基所检测82株临床菌株显示灵敏度为98.3%,特异度为100%。结论改良液体显色培养基检测GBS具有较高的灵敏度及特异度。

Objective To improve the composition of group B streptococcus(GBS)liquid chromogenic medium and improve the sensitivity of group B streptococcus liquid chromogenic medium screening.Methods A total of 15 strains of group B streptococcus(3 standard strains,12 clinical strains)and 9 standard strains of non-group B streptococcus were selected,and the optimal formula was selected by single factor optimization test and orthogonal test.A total of 62 strains of GBS and 20 strains of non-GBS were selected to prepare different concentrations to test the performance of the modified liquid medium.Results Gentamici n 8 g·L^(-1),naphthalinic acid 15 g·L^(-1),bovine heart extract powder 6.5 g·L^(-1),hydroxypropyl β-cyclodextrin 1.25 g·L^(-1),hemionine hydrochloride 3.5 g·L^(-1) and l-ornithine 1.1 g·L^(-1),rhamnose 0.4 g·L^(-1),heme chloride 12 mg·L^(-1),amphotericin B 4 mg·L^(-1),sheep serum 0.1%,DMF 0.005% were added in todd-hewitt basic broth.The P values of sheep serum,bovine heart extract powder and L-ornithine were 0.013,0.005,0.012,respectively.The sensitivity and specificity of 82 clinical strains detected by modified liquid chromogenic medium were 98.3% and 100%.Conclusion The improved liquid chromogenic medium has high sensitivity and specificity for the detection of GBS.