Rod-shaped gram-positive Bacillus anthracis bacteria in a cerebrospinal fluid sample stand out from round white blood cells. Violet stained gram-positive cocci and pink stained gram-negative rod-shaped bacteria. Gram-positive bacteria are bacteria that give a positive result in the Gram stain test.Gram-positive bacteria take up the crystal violet stain used in the test, and then appear to be purple-coloured when seen through a microscope.pecific to gram-positive bacteria is the presence of teichoic acids in the cell wall. Some of these are lipoteichoic acids, which have a lipid component in the cell membrane that can assist in anchoring the peptidoglycan.