TABLE 2.
Summary data (polystyrene beads) on inhibition of S. epidermidis biofilm formationa
| No. of duplicate evaluation | Mean no. of CFU/bead from various treatment regimens
|
|||
|---|---|---|---|---|
| A | B | C | D (reference) | |
| Run 1 | 1.9 × 105 (78.4) | 7.4 × 102 (99.9) | 1.7 × 105 (80.7) | 8.8 × 105 |
| Run 2 | 5.5 × 104 (72.9) | 4.8 × 102 (99.8) | 4.1 × 104 (79.8) | 2.1 × 105 |
| Run 3 | 1.3 × 105 (40.9) | 2.1 × 102 (99.9) | 3.2 × 104 (85.5) | 2.2 × 105 |
| Total mean (SEM) % inhibition | 64.1 (11.7)b | 99.9 (0.04)b | 82.0 (1.8) | |
The viable counts were compared with those recovered from beads incubated in the reference treatment (treatment D). S. epidermidis suspensions that gave a final inoculum size that ranged between 5 × 105 and 1 × 106 CFU/ml were introduced to one of the four treatment regimens and incubated with shaking (150 rpm) for 24 h at 37°C.
The statistical significance of the relative percentage of biofilm inhibtion was determined, and the difference between treatments A and B was significant (P = 0.03). However, only treatment B effectively inhibited biofilm formation. Comparisons of the mean among the groups were tested by one-way analysis of variance by Bonferroni multiple separation tests. Statistical analyses were performed with Stata software (version 7; Stata Corp.).