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.
Coccus. Cocci are round, spherical-shaped bacteria. They can occur as a single bacterium or be arranged in a pair, chain or cluster of bacteria depending on which type of coccus it is. These bacteria cause many different types of common diseases.ibrio. Vibrios are one of three types of bacteria with a spiral-like shape. Vibrios are comma-shaped bacteria that look like a curved rod. They typically live in aquatic environments. Vibrio cholera moves in a darting motion by a single flagellum, a whiplike structure, and is the bacteria that causes cholera.