Definition of retain. transitive verb. 1a : to keep in possession or useb : to keep in one's pay or service; specifically : to employ by paying a retainerc : to keep in mind or memory : remember.
However, some gram- positive bacteria may also have capsules. Examples for gram-negative bacteria with capsules: Escherichia â¦coli, Klebsiella pneumoniae, Salmonella. Examples for gram-positive bacteria with capsules : Bacillus megaterium, Streptococcus pyogenes, Sterptococcus pneumoniae.
Best Answer: Three main types of bacteria exist. The cocci, plural for coccus, bacteria have a spherical shape. In nature, these bacteria may exist as individuals cells or be grouped together. Cocci cells that are grouped in pairs, known as diplococci cells, are cells that do not fully separate through cell division.