Adhesion to and biofilm formation on IB3-1 cell monolayer of clinical isolates of S. maltophilia from CF patients. A. Adhesion levels of S. maltophilia to IB3-1 cell monolayers. Strains OBGTC9 and OBGTC10 showed the highest level of adhesiveness, significantly higher than for the other strains (** P < 0.001; ANOVA-test followed by Newman-Keuls multiple comparison post-test). B. Biofilm formed by S. maltophilia on IB3-1 cell monolayers. Strain OBGTC37 formed the highest amount of biofilm, significantly higher (** P < 0.001; ANOVA-test followed by Newman-Keuls multiple comparison post-test) than other strains tested. Results are expressed as means + SDs.