MC58Δ siaD Δ gapA-1 has a reduced ability to associate with HBME cells compared to MC58Δ siaD. The number of MC58ΔsiaD ΔgapA-1 cells associating was significantly lower than the capsule null (*P = 0.0008). Mean levels shown from three independent experiments, each using triplicate wells. Bars denote standard deviation. Cfu denotes colony forming units.