| 產品名稱： | 強化梭菌鑒別瓊脂；DRCA培養基；MPN法梭菌計數培養基 |
|---|---|
| 英文名稱： | Differential Reinforced Clostridial Agar；DRCA |
| 培養基類型： | 加富培養基 |
| 級別： | for microbiology |
| 品牌： | ELITE-MEDIA |
| 產品目錄號： | M1192-01、M1192-02 |
| 產品規格： | 250g、500g（添加劑需另購） |
| 產品外觀： | 淺棕色均一粉末。 |
| 顏色與澄清度： | 溶液加熱時呈淺琥珀色，冷卻后呈淺紅色，半透明，偶或有深色顆粒。 |
| 保存條件： | 密封，2-30ºC保存。 |
| 注意事項： | 避免呼入和皮膚接觸。 |
| 相關產品： | -- |
產品描述：
強化梭菌鑒別瓊脂（Differential Reinforced Clostridial Agar）簡稱DRCA培養基,用于培養和計數厭氧菌的芽孢，也用于梭狀芽孢桿菌的MPN法計數。用途：
DRCA用于厭氧型細菌芽孢的分離和增菌，特別是梭狀芽孢桿菌。DRCA培養基與DRCM培養基結合使用，檢測和鑒別梭狀芽孢桿菌。
向DRCA中添加多粘菌素B(70000 IU/L)能夠抑制不產芽孢的革蘭氏陰性菌的生長,提高培養基的選擇性。
原理：
強化梭菌鑒別瓊脂是在強化梭菌鑒別培養基(DRCM)中加瓊脂而來的。強化梭菌鑒別培養基是針對MPN（Most Probable Number）計數方法而設計的培養基。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長所需的營養成分。半胱氨酸作為還原劑。醋酸鈉起緩沖作用和部分篩選作用。淀粉吸附代謝毒素。梭狀芽孢桿 菌能夠將亞硫酸鹽還原成硫化物，生產硫化鐵。檸檬酸鐵和和亞硫酸鈉是硫化物指示系統，培養基變黑表明有硫化鐵生成。刃天青鈉是氧化指示劑，有氧條件下呈粉色，無氧條件下無色。配方與配制方法：
| 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 |
| 水合醋酸鈉 | 5 |
| 可溶性淀粉 | 1 |
| L-半胱氨酸鹽酸鹽 | 0.5 |
| 焦亞硫酸鈉 | 0.5 |
| 檸檬酸鐵銨 | 0.5 |
| 刃天青鈉 | 0.002 |
| 瓊脂 | 15 |
| pH7.1±0.2 |
配制方法：
1. 稱取42.5 g本品，加1 L去離子水溶解。
2. 邊攪動邊加熱，煮沸1min，使其完全溶解。
3. 121ºC滅菌15min。
實驗方法：
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.
結果分析
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.