A new medium for the enumeration and subculture of bacteria from potable water
A new medium for the enumeration and subculture of bacteria from potable water
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DOI：
10.1128/aem.49.1.1-7.1985
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发表时间：
1985-01
影响因子：
4.4
通讯作者：
D. Reasoner;E. Geldreich
中科院分区：
文献类型：
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作者：
D. Reasoner;E. Geldreich
平板计数琼脂是目前推荐的用于水和废水的标准细菌平板计数（35 ℃，48小时孵育）的培养基。然而，平板计数琼脂不允许许多可能存在于经处理的饮用水供应中的细菌生长。开发了一种新的培养基，用于异养平板计数分析和饮用水样品中分离的细菌的传代培养。命名为R2A的新培养基含有0.5g酵母提取物、0.5g Difco蛋白糖蛋白胨3号（Difco Laboratories）、0.5g酪蛋白氨基酸（Difco）、0.5g葡萄糖、0.5g可溶性淀粉、0.3g K2HPO4、0.05g MgSO4 × 7H2O、0.3g丙酮酸钠、和每升实验室质量水15克琼脂。用结晶K2HPO4或KH2PO4调节pH值至7.2，并在121 ℃下灭菌15 min。用涂布、膜过滤和倾注平板程序进行平行研究的结果表明，R2A培养基产生的细菌计数显著高于平板计数琼脂。对孵育温度影响的研究表明，计数的大小与孵育温度成反比。更长的孵育时间，长达14天，产生更高的计数和增加色素细菌的检测。在20 ℃下孵育14天后获得最大细菌计数。作为监测水处理过程和处理过的配水中异养细菌种群的工具，建议在28 ℃下培养5至7天的R2A铺展或膜滤板。（250字处删节）
Plate count agar is presently the recommended medium for the standard bacterial plate count (35 degrees C, 48-h incubation) of water and wastewater. However, plate count agar does not permit the growth of many bacteria that may be present in treated potable water supplies. A new medium was developed for use in heterotrophic plate count analyses and for subculture of bacteria isolated from potable water samples. The new medium, designated R2A, contains 0.5 g of yeast extract, 0.5 g of Difco Proteose Peptone no. 3 (Difco Laboratories), 0.5 g of Casamino Acids (Difco), 0.5 g of glucose, 0.5 g of soluble starch, 0.3 g of K2HPO4, 0.05 g of MgSO4 X 7H2O, 0.3 g of sodium pyruvate, and 15 g of agar per liter of laboratory quality water. Adjust the pH to 7.2 with crystalline K2HPO4 or KH2PO4 and sterilize at 121 degrees C for 15 min. Results from parallel studies with spread, membrane filter, and pour plate procedures showed that R2A medium yielded significantly higher bacterial counts than did plate count agar. Studies of the effect of incubation temperature showed that the magnitude of the count was inversely proportional to the incubation temperature. Longer incubation time, up to 14 days, yielded higher counts and increased detection of pigmented bacteria. Maximal bacterial counts were obtained after incubation at 20 degrees C for 14 days. As a tool to monitor heterotrophic bacterial populations in water treatment processes and in treated distribution water, R2A spread or membrane filter plates incubated at 28 degrees C for 5 to 7 days is recommended.(ABSTRACT TRUNCATED AT 250 WORDS)