Mahesh P P, Kolape Jaydeep, Sultana Hameeda, Neelakanta Girish
Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
Advanced Microscopy and Imaging Center, College of Arts and Sciences, University of Tennessee, Knoxville, TN 37996, USA.
Microorganisms. 2025 Mar 14;13(3):662. doi: 10.3390/microorganisms13030662.
is an obligate intracellular Gram-negative bacterium that causes human granulocytic anaplasmosis. Assessing the number of these bacteria is important for in vitro and in vivo infection studies. Colony count is used to set references for the multiplicity of infections in the case of culturable bacteria. However, the number of bacteria present inside the host cells, in which the bacteria are maintained, can be considered in the case of obligate intracellular bacteria. McFarland standards are a series of turbidity-based standards used to visually assess the approximate number of culturable bacteria. The turbidity of each standard can be related to their respective absorbances or optical densities (ODs). In this study, we describe a simple method to assess the approximate number of based on McFarland standards. The ODs of cell-free crude extracts of were used to assess the approximate number of bacteria while considering that the cell debris also contributes to the ODs. The consistency of this method was also tested using the bacterial cultures grown at different times. In summary, we provide a simple method to estimate the number of obligate intracellular bacteria for use in in vitro infection studies.
是一种 obligate intracellular 革兰氏阴性细菌，可引起人类粒细胞无形体病。评估这些细菌的数量对于体外和体内感染研究很重要。对于可培养细菌，菌落计数用于设定感染复数的参考标准。然而，对于 obligate intracellular 细菌，可考虑宿主细胞内维持的细菌数量。麦克法兰标准是一系列基于浊度的标准，用于目视评估可培养细菌的大致数量。每个标准的浊度可与其各自的吸光度或光密度（OD）相关。在本研究中，我们描述了一种基于麦克法兰标准评估 的大致数量的简单方法。考虑到细胞碎片也对 OD 有贡献， 的无细胞粗提物的 OD 用于评估细菌的大致数量。还使用在不同时间培养的细菌培养物测试了该方法的一致性。总之，我们提供了一种简单方法来估计用于体外感染研究的 obligate intracellular 细菌数量。
