| 培养基名称 | 抗生素测定培养基3号；测定肉汤 |
|---|---|
| 英文名称: | Antibiotic Assay Medium No.3；Assay Broth |
| 培养基类型: | 营养培养基 |
| 产品目录号: | M104-01 |
| 产品规格: | 250g、500g、5kg |
| 保存条件: | 密封，阴凉干燥处保存。制备好的培养基2-8°C避光保存。 |
| 产品性状: |
麦秸色粉末。 浅黄色透明液体。 |
| 注意事项: | 避免摄入、呼入、皮肤接触。配制时在通风橱中进行，戴口罩、手套、护目镜。 |
| 相关产品: | -- |
产品描述：
抗生素测定培养基3号(Antibiotic Assay Medium No.3)也称测定肉汤，用于浊度法或者系列稀释法测定很多种抗生素效价。该培养基配方按照美国药典USP规定配制。
抗生素测定培养基3号工作原理
比浊法测定抗生素（Turbidimetric antibiotic assay）基于检测微生物在含有均匀分布的抗生素的培养基中生长速度的改变或受抑制。该方法仅适合澄清的样品。
蛋白胨、牛肉浸粉和酵母提取物提供重要的营养和生长因子。氯化钠维持渗透压平衡。磷酸盐是缓冲剂。葡萄糖是碳源和能量来源。
抗生素测定培养基3号的用途：
推荐用于微生物法测定以下抗生素:
阿米卡霉素Amikacin，卷曲霉素Capreomycin，氯霉素Chloramphenicol，金霉素Chlortetracycline，环丝氨酸Cycloserine，地美环素Demeclocycline，二双氢链霉素Dihydrostreptomycin，多西环素Doxycycline，短杆菌肽Gramicidin，卡那霉素Kanamycin，甲烯土霉素Methacycline，土霉素Oxytetracycline，吡咯烷甲基四环素Rolitetracycline，链霉素Streptomycin，四环素Tetracycline，托普霉素Tobramycin，醋竹桃霉素Troleandomycin
抗生素测定培养基3号配方与配制方法
| 成分 | g / L |
| 蛋白胨 | 5 |
| 酵母提取物 | 1.5 |
| 牛肉浸粉 | 1.5 |
| 葡萄糖 | 1 |
| 氯化钠 | 3.5 |
| 磷酸氢二钾 | 3.68 |
| 磷酸二氢钾 | 1.32 |
| pH 7.0±0.05 |
配制方法：
1. 称取17.5g本产品，用1000ml纯水重悬。
2. 加热使培养基完全溶解。
3. 121°C灭菌15min。
实验方法
Prepare slant culture of Bacillus subtillis (ATCC 6633) on Assay Medium No. 1 and incubate for 16-24 hours at 37°C. Wash the growth with sterile distilled water and transfer it to surface of Assay Medium No. 32 and incubate at 37°C for 7 days. Wash the growth with sterile distilled water. Heat to 65°C for 30 minutes in water bath. Centrifuge, decant the supernatant and resuspend the cells. Repeat this for 3 minutes in water bath. Dilute suspension with sterile distilled water (1 + 50) to read 20%T on sprectrophotometer at 530 nm before use.
Use single inoculated agar layer. Optimum concentration of suspension of Bacillus subtillis is determined prior to assay to be added to Medium M to obtain inhibition zone of adequate size (17.5 ± 2.5 mm with 1.0 μg/ml). For actual assay add appropriate amount of suspension to sterile, molten medium M (pH 6.0). Mix and add 6 ml to each plate. Prepare plates 2.5 3 hours before use. Weigh 1.0 g premix. Transfer to flask and add 100 ml methanol. Shake vigorously for 3 minutes and dilute with methanol. Dilute 4 ml of this to 100 ml methanol. Further dilute 3 ml with 22 ml methanol and water to 100 ml (1 ml= ca/μg lasalocid Na/ml 25% methanol). Prepare final concentration of feed to 0.0075%. For more details refer AOAC.
Using lasalocid, sodium obtain standard response line, assay solution. Place cylinders on each plate and alternatively fill with reference concentration and other standard concentration. Incubate at 35-36°C. Calculate zone diameters of L (Low concentration giving measurable zone) and H (Highest concentration) of standard response line and connect with straight line. This corrected reference point is used for sample calculations. Average the 9 readings of reference concentration and 9 readings of assay solution. If assay solution gives larger average than reference concentration, add difference between them to reference point on standard response line. If the assay solution gives lower average than reference concentration, subtract the difference from reference point. Using the corrected value of assay solution, amount of antibiotic is determined.
实验结果
ATCC标准菌株 测定抗生素 温度与时间 大肠埃希氏菌ATCC10536 Chloramphenicol 32-35°C/24 h 肺炎克雷伯菌 ATCC10031 Capreomycin 36-37.5°C/16-24 h Dihydrostreptomycin Streptomycin Troleandomycin 金黄色葡萄球菌ATCC29737 Amikacin 32-35°C/24 h Chlortetracycline Cycloserine Demeclocycline Doxycycline Kanamycin Lincomycin Methacycline Oxytetracycline Rolitetracycline Tetracyclin Tobramycin 希氏肠球菌ATCC10541 Gramicidin 36-37.5°C/16-18 h 金黄色葡萄球菌ATCC9144 Tylosin 35-39°C/16-18 h
