The antibiofilm effects of docosahexaenoic acid

The ability of bacteria to form biofilms allows for recalcitrance against conventional antibiotic therapies (Potera, 1999). Therefore, this has contributed to the prevalence of biofilm acquired infections (BAI) clinically (Percival and Kite, 2018) which has resulted in increased morbidity and mortality amongst patients, with immunocompromised patients at risk in particular (Donlan, 2002). Biofilm formation on abiotic and biotic surfaces has enabled bacteria to colonise major organs and medical devices, such as within the lungs, on implant surfaces, contact lenses, and urinary catheters (Vinh and Embil, 2005; Percival et al., 2012; Seth et al., 2012). Docosahexaenoic acid (DHA) is a poly-unsaturated fatty acid known to exhibit antibiofilm and antimicrobial effects (Sun et al., 2017; Kim et al., 2018). Our research has found that DHA possesses strong anti-biofilm effects against Klebsiella pneumoniae and Enterococcus faecalis at low mM concentrations. DHA was capable of reducing biofilm formation by both K. pneumoniae and E. faecalis by approximately 60%. It is believed that this is the first time these effects have been reported. We have also have evidence that DHA in conjunction with an antibiotic is better at reducing biofilm formation by these strains better then either alone.

To date, there is much debate into how DHA exerts these anti-biofilm effects. DHA has been reported to distort bacterial membrane’s therefore, impacting biofilm formation (Sun et al., 2017). We aim to elucidate the precise mechanism of action by utilising a number of genetic approaches alongside the dynamic flow cell system and confocal microscopy.