(a) The pour plate method 采用培养平板计数法要求操作熟练 1.0 or 0. 1 ml 0.1ml 准确,否则难以得到正确的结果: Inoculate Inoculate plate empty plate 样品充分混匀 Bacterial dilution 每支移液管及涂布棒只能接触一个 稀释度的菌液; (Add melted nutrient agar 同一稀释度三个以上重复取平均 值 Swirl to mⅸ 每个平板上的菌落数目合适,便于 准确计数 ( Colonies Colonies grow grow in and only on surface on solidified of medium 个菌落可能是多个细胞一起形成,所以在科研中一般用 菌落形成单位( colony forming units,CFU)来表示,而 不是直接表示为细胞数
采用培养平板计数法要求操作熟练 、准确，否则难以得到正确的结果： 样品充分混匀； 每支移液管及涂布棒只能接触一个 稀释度的菌液； 同一稀释度三个以上重复,取平均 值； 每个平板上的菌落数目合适，便于 准确计数； 一个菌落可能是多个细胞一起形成，所以在科研中一般用 菌落形成单位（colony forming units， CFU）来表示，而 不是直接表示为细胞数
膜过滤培养法 Figure 6.17 Counting bacteria by filtration. (a)The bacteria in 100 ml of water were sieved out onto the surface of a membrane filter.(b) Such a filter, with the bacteria much more widely spaced was placed on a pad saturated with quid nutrient medium, and the individual bacteria grew into visible colonies. One hundred twenty four colonies are visible, so we would record 124 bacteria per 100 ml of water sample Bacteria can be counted by filtra tion when their quantity is very mall (b) SEM2 um 当样品中菌数很低时,可以将一定体积的湖水、海水或饮用水等样 品通过膜过滤器,然后将将膜转到相应的培养基上进行培养,对形 成的菌落进行统计
2、膜过滤培养法 当样品中菌数很低时，可以将一定体积的湖水、海水或饮用水等样 品通过膜过滤器，然后将将膜转到相应的培养基上进行培养，对形 成的菌落进行统计
3、 The most probable number method(液体稀释法) 主要适用于只能进行液体培养的微生[n 95% Confidence MPN Index/ 物,或采用液体鉴别培养基进行直接【0 100ml Lower 鉴定并计数的微生物 273 12 15 4-4-0 Volume of Inoculum for Tubes of Nutrient Medium Number of Positive 5-0-0 Each Set of ( Sets of Five Tubes) 50-1 Five Tubes Tubes in Set mn日目目日 5-2-0 50 0日 2000000 222 0.1ml 5-3-1 110 5-3-2 Figure 6.18 The most probable number(MPN) method. In this example, there are three sets of tubes and five tubes in each set. Each tube in the first set of five tubes receives 10 ml of the inoculum, such as a sample of water. Each tube in the second set of five tubes receives I ml of the sample, and the third set, 0. 1 ml each. There were enough bacteria in the sample that all five tubes in the first set showed bacterial growth and were recorded as positive. In the second set, which received only one-tenth as much inoculum, only three tubes were positive. In 对未知样品进行十倍稀释,然后根据估算取三个连续的稀释度 平行接种多支试管,对这些平行试管的微生物生长情况进行统 计,长菌的为阳性,未长菌的为阴性,然后根据数学统计计算 出样品中的微生物数目
3、The most probable number method（液体稀释法） 主要适用于只能进行液体培养的微生 物，或采用液体鉴别培养基进行直接 鉴定并计数的微生物。 对未知样品进行十倍稀释，然后根据估算取三个连续的稀释度 平行接种多支试管，对这些平行试管的微生物生长情况进行统 计，长菌的为阳性，未长菌的为阴性，然后根据数学统计计算 出样品中的微生物数目
4、显微镜直接计数法 1)常规方法: Fiqure 6.19 Direct Grid with 25 large squares microscopic count of bacteria with a Petroff-Hausser cell Cover glass counter. The average number of cells within a large square multiplied by a factor of 1, 250,000 gives the number of bacteria per milliliter Direct microscopic counts are 缺点: 3 Microscopic count: All cells in several large squares are 不能区分死菌与活菌; counted, and the numbers are averaged. The large square 不适于对运动细菌的计数 shown here has 14 bacterial cells The volume of fluid over the 需要相对高的细菌浓度; large square is 1/1, 250,000 is known of a milliliter. If it contains 14 own cells, as shown here, then there 个体小的细菌在显微镜下难以观察:m are 14 times 1,250,000 (17, 500,000)cells in a milliter
4、显微镜直接计数法 1）常规方法： 缺点： 不能区分死菌与活菌； 不适于对运动细菌的计数； 需要相对高的细菌浓度； 个体小的细菌在显微镜下难以观察；