Department of Microbiology, Basic Medical Sciences, Panjab University, Chandigarh, India.
Department of Microbiology, Basic Medical Sciences, Panjab University, Chandigarh, India.
J Virol Methods. 2018 Dec;262:1-5. doi: 10.1016/j.jviromet.2018.09.001. Epub 2018 Sep 10.
Phage enumeration is a basic prerequisite for application of phages in industrial, medical and other processes. Double layer agar (DLA) plaque assay is the classical method employed for isolation, detection as well as enumeration of phage particles in a solution. However, DLA method is considered cumbersome due to its specific temperature requirements and need for one petriplate with two agar layers for each phage sample. We are proposing a drop cast method for enumeration of phages which is comparatively easier and cost effective than classical DLA method as single layer of agar without any specific temperature condition is required. Added advantage of this method is that 7-10 dilutions of phage suspension can be enumerated on a single agar plate in contrast to one dilution per plate as required in DLA method. Although standard deviation in phage count was higher in the proposed method than DLA method, still drop cast method provided first-approximation phage titer which can be further validated by DLA method for more accuracy. Hence, the present method can be considered reliable, easy and cost effective for determining approximate phage count in an unknown phage suspension.
噬菌体计数是噬菌体在工业、医疗和其他过程中应用的基本前提。双层琼脂（DLA）平板法是用于分离、检测和计数溶液中噬菌体颗粒的经典方法。然而，由于其特定的温度要求和每个噬菌体样品需要一个具有两层琼脂的培养皿，DLA 方法被认为很繁琐。我们提出了一种用于噬菌体计数的滴铸法，与经典的 DLA 方法相比，该方法更简单、更经济，因为它只需要一层琼脂，而不需要任何特定的温度条件。该方法的另一个优点是，与 DLA 方法每个平板只能进行一个稀释度的噬菌体悬浮液相比，在单个琼脂平板上可以对 7-10 个稀释度的噬菌体悬浮液进行计数。尽管与 DLA 方法相比，所提出方法的噬菌体计数标准偏差较高，但滴铸法仍提供了噬菌体效价的初步近似值，可通过 DLA 方法进一步验证以获得更高的准确性。因此，该方法可用于确定未知噬菌体悬浮液中的近似噬菌体数量，具有可靠、简单和经济高效的特点。
