Carey R B, Gross K C, Roberts R B
J Infect Dis. 1975 Jun;131(6):722-6. doi: 10.1093/infdis/131.6.722.
Strains of nutritional-variant viridans Streptococcus were isolated from two patients with bacterial endocarditis and from one patient with a pancreatic abscess. All three strains grew as satellite colonies of other bacteria but did not grow as pure cultures in media lacking sufficient thiol compounds. For one-half maximal growth these organisms required the addition of one of the active forms of the B6 vitamin, pyridoxal with HCl (0.16-1.45 mug/ml) or pyridoxamine dihydrochloride (0.67-2.0 mug/ml), or addition of l-cysteine (0.235-0.425 mg/ml) to routine bacteriological media. The active forms of vitamin B6 are essential coenzymes in the synthesis of l-cysteine and of other thiol compounds. Use of media supplemented with 0.001 percent pyridoxal with HCL led to identification of the strains as Streptococcus mitior (mitis). Incorporation of pyridoxal with HCl, pyridoxamine dihydrochloride, or l-cysteine into media is recommended for the isolation and identification of vitamin B6-dependent viridans streptococci.
从两名患有细菌性心内膜炎的患者和一名患有胰腺脓肿的患者中分离出营养变异型草绿色链球菌菌株。所有这三株菌株都作为其他细菌的卫星菌落生长，但在缺乏足够硫醇化合物的培养基中不能作为纯培养物生长。为了实现最大生长量的一半，这些微生物需要添加维生素B6的一种活性形式，即盐酸吡哆醛（0.16 - 1.45微克/毫升）或盐酸吡哆胺（0.67 - 2.0微克/毫升），或者向常规细菌学培养基中添加L-半胱氨酸（0.235 - 0.425毫克/毫升）。维生素B6的活性形式是L-半胱氨酸和其他硫醇化合物合成中必不可少的辅酶。使用添加了0.001%盐酸吡哆醛的培养基可将这些菌株鉴定为轻型链球菌（缓症链球菌）。建议在培养基中加入盐酸吡哆醛、盐酸吡哆胺或L-半胱氨酸，用于分离和鉴定依赖维生素B6的草绿色链球菌。
