What are 2 conditions in which an organism might stain gram variable?

An organism might stain gram variable due to the presence of a cell wall structure that is intermediate between gram-positive and gram-negative bacteria, often seen in some members of the Actinobacteria or Firmicutes phyla. Additionally, factors such as the age of the culture, where older cells may lose their ability to retain the crystal violet stain, or exposure to certain environmental stresses, such as changes in temperature or pH, can also lead to a gram variable result.