1.1本试验方法包括使用吖啶橙荧光直接显微镜计数程序检测和计数水生细菌。本试验方法适用于环境水和饮用水。 1.2某些类型的碎屑和其他微生物可能在吖啶橙染色的涂片中发出荧光。 1.3所述程序需要经过培训的微生物学家或技术人员，他们能够在高倍镜下根据形态学将细菌与其他荧光体区分开来。 1.4使用强光可以分化单个细菌，其中还原的甲赞沉积在极性末端。 1.5约10 4. 通过本试验方法进行检测需要每毫升细胞数。 1.6允许检测甲赞沉淀物的最小细胞大小由0.4 m的细菌表示。 2. 1.7 本标准无意解决与其使用相关的安全问题（如有）。 本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 ====意义和用途====== 细菌密度测量通常是建立细菌与其他生化过程之间关系的第一步。 5. 众所周知，经典平板计数程序低估了细菌密度，而表观荧光直接显微镜程序更准确地描述了水样中不活动或休眠和活细胞的总数。吖啶橙INT-formazan还原技术提供了有关细菌总浓度以及积极呼吸并因此参与降解过程的细菌比例的信息。 吖啶橙INT-formazan还原技术既定量又精确。 该程序适用于所有淡水和海洋环境中的浮游和表层底栖细菌的计数。 该过程可用于调查研究，以表征环境水体的细菌密度和活性。

1.1 This test method covers the detection and enumeration of aquatic bacteria by the use of an acridine-orange epifluorescence direct-microscopic counting procedure. This test method is applicable to environmental waters and potable waters. 1.2 Certain types of debris and other microorganisms may fluoresce in acridine-orange stained smears. 1.3 The procedure described requires a trained microbiologist or technician who is capable of distinguishing bacteria from other fluorescing bodies on the basis of morphology when viewed at higher magnifications. 1.4 Use of bright light permits differentiation of single bacteria where reduced formazan is deposited at the polar ends. 1.5 Approximately 10 4 cells/mL are required for detection by this test method. 1.6 Minimal cell size which allows the detection of formazan deposits is represented by bacteria of 0.4 m. 2 1.7 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== Measurement of bacterial densities is generally the first step in establishing a relationship between bacteria and other biochemical processes. 5 It is known that the classical plate count procedure underestimates bacterial densities while the epifluorescence direct microscopic procedure more accurately depicts the total numbers of nonviable or dormant and viable cells in a water sample. The acridine-orange INT-formazan reduction technique provides information on the total concentrations of bacteria as well as that proportion which are actively respiring and thus involved in degradative processes. The acridine-orange INT-formazan reduction technique is both quantitative and precise. This procedure is ideal for enumerating both pelagic and epibenthic bacteria in all fresh water and marine environments. The process can be employed in survey studies to characterize the bacteriological densities and activities of environmental waters.