| 产品名称： | 强化梭菌鉴别琼脂；DRCA培养基；MPN法梭菌计数培养基 |
|---|---|
| 英文名称： | Differential Reinforced Clostridial Agar；DRCA |
| 培养基类型： | 加富培养基 |
| 级别： | for microbiology |
| 品牌： | ELITE-MEDIA |
| 产品目录号： | M1192-01、M1192-02 |
| 产品规格： | 250g、500g（添加剂需另购） |
| 产品外观： | 浅棕色均一粉末。 |
| 颜色与澄清度： | 溶液加热时呈浅琥珀色，冷却后呈浅红色，半透明，偶或有深色颗粒。 |
| 保存条件： | 密封，2-30ºC保存。 |
| 注意事项： | 避免呼入和皮肤接触。 |
| 相关产品： | -- |
产品描述：
强化梭菌鉴别琼脂（Differential Reinforced Clostridial Agar）简称DRCA培养基,用于培养和计数厌氧菌的芽孢，也用于梭状芽孢杆菌的MPN法计数。用途：
DRCA用于厌氧型细菌芽孢的分离和增菌，特别是梭状芽孢杆菌。DRCA培养基与DRCM培养基结合使用，检测和鉴别梭状芽孢杆菌。
向DRCA中添加多粘菌素B(70000 IU/L)能够抑制不产芽孢的革兰氏阴性菌的生长,提高培养基的选择性。
原理：
强化梭菌鉴别琼脂是在强化梭菌鉴别培养基(DRCM)中加琼脂而来的。强化梭菌鉴别培养基是针对MPN（Most Probable Number）计数方法而设计的培养基。配方中的蛋白胨、酵母提取物、牛肉提取物和葡萄糖提供梭菌生长所需的营养成分。半胱氨酸作为还原剂。醋酸钠起缓冲作用和部分筛选作用。淀粉吸附代谢毒素。梭状芽孢杆 菌能够将亚硫酸盐还原成硫化物，生产硫化铁。柠檬酸铁和和亚硫酸钠是硫化物指示系统，培养基变黑表明有硫化铁生成。刃天青钠是氧化指示剂，有氧条件下呈粉色，无氧条件下无色。配方与配制方法：
| 成分 | g/L |
| 胰蛋白胨 | 5 |
| 蛋白胨 | 5 |
| 牛肉提取物 | 8 |
| 酵母提取物 | 1 |
| D-葡萄糖 | 1 |
| 水合醋酸钠 | 5 |
| 可溶性淀粉 | 1 |
| L-半胱氨酸盐酸盐 | 0.5 |
| 焦亚硫酸钠 | 0.5 |
| 柠檬酸铁铵 | 0.5 |
| 刃天青钠 | 0.002 |
| 琼脂 | 15 |
| pH7.1±0.2 |
配制方法：
1. 称取42.5 g本品，加1 L去离子水溶解。
2. 边搅动边加热，煮沸1min，使其完全溶解。
3. 121ºC灭菌15min。
实验方法：
1. Prepare serial 10-fold dilutions of the sample in 1/4 strength Ringer’s solution or 0.1% peptone water.2. Depending on the amount of the initial sample, transfer 1 mL or 0.1 mL of the appropriate dilution, prepared in step 1, to the bottom of a molten (45-50°C) DRCA tube.Prepare a duplicate tube using the same procedure.
3. Tighten the caps on the tubes.
4. Heat one of the duplicate DRCA tubes prepared in step 2 to 80 ± 1°C for 10 minutes to kill vegetative cells.
5. Incubate both tubes, heat-shocked and non-heat-shocked, at 35 ± 1°C for 5 days; examine for sulfite reduction. Non-heat-shocked cultures showing blackening must be heat shocked and subcultured to DRCA for confirmation.
其它方法
Inoculate samples onto the surface of agar plates using the streak plate or spread plate technique. Samples may be inoculated into DRCA using the pour plate technique. Agar in agar deeps may be inoculated using the stab technique. DRCA may be used to overlay the membrane filter in the membrane filter technique. Incubate plates and tubes at 35 ± 1°C for 24-48 hours under anaerobic conditions. Agar deeps may be incubated under aerobic conditions when following the Prickett tube method.
结果分析
The presence of clostridia is presumptively indicated by blackening in the Agar. Heat-shocked tubes showing blackening should be considered confirmatory for the presence of sulfite-reducing clostridia.
