Figure
6 : Representative microscopic images of Alcian blue staining and
comparison of RGB ratio of samples stained with Alcian blue. Error bars
were produced from the standard deviation of six replicates. (n=8, mean
± SEM) **** P<0.0001 (using unpaired t-tests).
Antibiotic Treatment Test
The effect of antibiotic treatment on biofilms grown in different
interfaces was evaluated to understand the differences in biofilm
susceptibility and to validate our model as a more realistic screening
tool in biofilm management. The results of the antibiotic susceptibility
test in the range of 50-1600μg/mL for the ALI and LLI interfaces are
depicted in Fig. 7. Data is presented using the number of detached,
attached and total CFUs. CIP induced a concentration-dependent decrease
for the biofilm, detached bacteria, and total counts for both
interfaces. Statistical differences were only observed for
concentrations from 800μg/mL, and biofilms were not eradicated at the
highest concentration tested (1600μg/mL). This is probably due to the
biofilm’s complex structure and the presence of EPS, which creates an
antibiotic gradient in the biofilm community
[5-8].
The antibiotic effect on the biofilms was further corroborated by the
SEM images (Fig. 8), showing the differences in biofilm density across
the membranes when compared to the control (without antibiotic).