May be involved in synthesis of N-acetyltrideoxygalactose, a component of exopolysaccharide EPS I which functions as a virulence factor. UDP-N-acetyl-alpha-D-glucosamine = UDP-N-acetyl-alpha-D-mannosamine Glycan metabolism; exopolysaccharide EPS I biosynthesis. Belongs to the UDP-N-acetylglucosamine 2-epimerase family.