HiMedia – M1840andM1966 HiCrome™ Strep B Selective Agar Base / Modified

Principle and Interpretation
Group B Streptococcus infection is a leading illness causing death in newborns. Group B streptococci can also cause serious diseases in pregnant women, the elderly, and adults with other illnesses. GBS normally reside in the vagina of women and rectum of men and women (1). In newborns, group B strep is the most common cause of sepsis (infection of the bloodstream) and meningitis (infection of the lining and fluid surrounding the brain) and a common cause of pneumonia. In adults, group B strep can rarely lead to serious bloodstream infections, urinary tract infections, skin infections, and pneumonia, especially in people with weak immune systems. Heavy colonization of the maternal genital tract is associated with colonization of infants and risk of neonatal disease (2). The sample collection is usually done by collection of vaginal and rectal swab between 35 and 37 weeks of pregnancy. The swab is then processed on HiCrome™ Strep B Selective Agar Base. For the conventional methods optimum recovery is however achieved by selective enrichment into Todd Hewitt broth with colistin and nalidixic acid and then subculture on Blood Agar (3, 4). Protein hydrolysate, peptone special and yeast extract provides nitrogenous and carbonaceous compounds, long chain amino acids, vitamins and essential nutrients for the growth of Streptococci. Buffers present provides buffering to the medium. Selective agents in the medium inhibits accompanying flora. One of the substrate in the chromogenic mixture is cleaved by beta glucosidase possesed by Group B Streptococci resulting in blue coloured colonies in M1840 and purple coloured colonies in M1966 w/ Phenol red as indicator dye. Other streptococci in (M1966) either give blue or bluish green coloured colonies with yellow background.

原理與解釋
B組鏈球菌感染是導致新生兒死亡的主要疾病。 B組鏈球菌也可能導致孕婦，老年人和其他患有其他疾病的成年人患上嚴重疾病。 GBS通常位於男性和女性的女性和直腸陰道內（1）。在新生兒中，B組鏈球菌是敗血症（血液感染）和腦膜炎（內膜感染）的最常見原因 和腦周圍的液體）和肺炎的常見原因。在成人中，B組鏈球菌很少會導致嚴重的血流感染，尿路感染，皮膚感染和肺炎，特別是在免疫系統較弱的人群中。母體生殖道的嚴重定植與嬰兒的定植和新生兒疾病的風險相關（2）。 樣本採集通常通過在懷孕35至37週之間收集陰道和直腸拭子來完成。然後在HiCrome™Strep B選擇性瓊脂基質上處理拭子。然而，對於常規方法，通過用粘菌素和萘啶酸選擇性富集到Todd Hewitt肉湯中然後在血瓊脂上進行傳代培養來實現最佳恢復（3,4）。 蛋白質水解產物，蛋白腖特殊和酵母提取物為鏈球菌的生長提供含氮和含碳化合物，長鏈氨基酸，維生素和必需營養素。存在的緩衝器為介質提供緩衝。培養基中的選擇性試劑抑制伴隨的菌群。其中一個基板 顯色混合物被B組鏈球菌所具有的β葡糖苷酶切割，產生M1840中的藍色菌落和M1966中的紫色菌落，其中酚紅為指示劑染料。 （M1966）中的其他鏈球菌或者給出具有黃色背景的藍色或帶藍綠色的菌落。