The glycocalyx can be identified by negative staining techniques. The glycocalyx is referred to as a capsule if it is firmly attached to the cell wall, or as a slime layer if loosely attached. Pathogens such as Streptococcus pneumoniae can cause pneumonia if protected by a capsule. Permit bacteria to adhere to cell surfaces and structures such as medical implants, catheters and so on. This is an important first step in colonization and sometimes leads to disease.
Capsules can be a source of nutrients and energy to microbes.
Purified polysaccharide vaccines also exist for streptococcal pneumonia and meningococcal meningitis. Flagella Bacterial flagella consist of a filament and a hook which pierces the cell wall and attaches to the base of ring-like structures. The flagella rotate and move the bacterium in a fashion similar to a propellor. Gram positive bacteria have one set of rings which anchor the flagellum into the cell while gram negative cells have two sets of rings. Flagella may also be identified by special staining techniques.