**5. Flagella**

The bacterial flagellum is protrudes from the cell body in the form a long, thin filament that consists of the basal body, the hook and the filament. The basal body is rooted in the cytoplasmic membrane having three rings the outer membrane lipopolysaccharide (L) ring, the peptidoglycan (P) ring and the cytoplasmic membrane supra-membrane (MS) ring. The hook is exposed to the surface and is a flexible universal joint between the filament and basal body. The filament is made of polymerized flagellin monomers (up to 20,000 subunits) capped by the flagellar cap, FliD, which acts as mucin adhesion [22, 23].

The initial attachment of the bacteria needs flagella and have involvement in maturation of biofilm. Klausen et al. reported that the initial microcolony formation is occurred by clonal growth and flagella are not involved in biofilm development in *P. aeruginosa* during attachment [24].
