55 ± 0.07 log [CFU/cm2]) and Lotrafilcon B (7.38 ± 0.06 log [CFU/cm2]) than on Etafilcon A (7.14 ± 0.09 log [CFU/cm2]) and Comfilcon A (7.07 ± 0.05 log [CFU/cm2]). Although there

were differences in kinetics, biofilms grown for 72 h were used in qualitative experiments because variance in biofilm formation was minimised at this point of time, and biofilms had reached a stationary phase on most of the CL materials. Table 5 Significance of the differences between the viable cell counts of P. aeruginosa SG81 on different CL materials Incubation time Contact lens material   2 3 4 Independent       1 < 0.001 0.987 < 0.001 2 - < 0.001 0.980 3 - - < 0.001 24 h       1 0.070 0.057 0.093 2 - 0.001 0.998 3 - - 0.001 48 h       1 0.001 0.008 0.001 2 - 0.515 0.743 3 - - 0.154 72 h       1 < 0.001 0.601 0.006 2 - < 0.001 0.033 3 - - 0.001 Tukey's HSD Post-hoc test: 1. Acuvue 2 (Etafilcon A); 2. Proclear selleck inhibitor (Omafilcon A); 3. Biofinity (Comfilcon A); 4. Air Optix (Lotrafilcon B). P ≤ 0.05 was considered statistically significant. Characterisation PD-0332991 in vivo of biofilms on contact lenses using CLSM and SEM To characterise the predominant

biofilm structures on various CL materials (Figure 4), biofilms were stained with CTC for observation of the viable bacterial cells. The biofilms of the various CL materials often showed a heterogeneous EPS structure, visible as ConA Alexa Fluor 488, green stained fluorescent, cloud-like regions. Bacterial selleck antibody inhibitor adhesion densities on Etafilcon A and Comfilcon A were obviously lower than on Omafilcon A and Lotrafilcon B, which correlated with the findings of the viable cell count analysis. Figure 4 Predominant P. aeruginosa biofilm structures depend on contact lens materials after 72 h growth. Transmitted light micrographs: deposits and adherent bacterial cells on the contact lenses are visible as grey dots and shadows. CTC staining of the biofilms (red) shows the metabolic activity of viable bacteria cells. ConA Alexa Fluor 488 staining of the biofilms (green) verifies the presence of alginate within the biofilm matrix. Superimposition

of the transmitted light micrographs and the fluorescence micrographs (merge) shows the correlation of the CTC and ConA Alexa Fluor 488 staining regions. Bar = 20 μm. Among the observed, predominant biofilm morphologies, various structures were characterised, independent of the CL material. For example, Figure 5 depicts a heterogeneous biofilm stained with DAPI and CTC for examining the proportion of total and viable bacterial cells. A comparison of DAPI and CTC fluorescent regions showed that most of the cells were viable. Additionally, P. aeruginosa SG81 biofilms were found to occur either in a homogeneous, thin, dispersed structure (Figure 6) or in a more heterogeneous, compact form (Figure 5). Whilst both structures were found on every CL, the heterogeneous form was predominant.