Biofilm growth is a universal survival strategy for bacteria, providing an effective and resilient approach for survival in an otherwise hostile environment. In the context of an
infection, a biofilm provides resistance and tolerance to host immune defenses and
antibiotics, allowing the biofilm population to survive and thrive under conditions that would destroy their planktonic counterparts. Therefore, the disruption of the biofilm is a key step in eradicating persistent
bacterial infections, as seen in many types of
chronic disease. In these studies, we used both in vitro minimum biofilm eradication concentration (MBEC) assays and an in vivo model of chronic biofilm
infection to demonstrate the biofilm-disrupting effects of an
alginate oligomer, OligoG CF-5/20. Biofilm
infections were established in mice by tracheal instillation of a mucoid clinical isolate of Pseudomonas aeruginosa embedded in
alginate polymer beads. The disruption of the biofilm by OligoG CF-5/20 was observed in a dose-dependent manner over 24 h, with up to a 2.5-log reduction in CFU in the infected mouse lungs. Furthermore, in vitro assays showed that 5% OligoG CF-5/20 significantly reduced the MBEC for
colistin from 512 μg/ml to 4 μg/ml after 8 h. These findings support the potential for OligoG CF-5/20 as a biofilm disruption agent which may have clinical value in reducing the microbial burden in chronic biofilm
infections.