<prompt> Which among the following organism cant be demonstrated by gram staining?BorreliaspirochetesStrep.pneumoniaeMycoplasma  <response>: Ans: b SpirochetesBorrelia- gram negativeStrep pneumonia- gram positiveMycoplasma- gram negativeGram positive bacteria becomes gram negative when the cell wall is damaged.Even though spirochetes are grouped under gram negative organism, it is not a preferred test for diagnosing spirochetal disease. 