Antimicrobial, Anti-adhesive and Anti-biofilm Actions of Rhamnolipids on ESKAPE Pathogens.

Abstract

The aim of this study was to test the antimicrobial, anti-adhesive and anti-biofilm activities of a rhamnolipid extracted from Pseudomonas aeruginosa UKMP14T previously isolated from oil contaminated soil in Malaysia against ESKAPE (i.e. multidrug resistant) pathogens. Zones of inhibition in an agar well diffusion assay were observed at 50μg mL-1 concentrations of rhamnolipid for all the ESKAPE bacteria. The MIC and MBC values ranged between 7.81-62.5µg mL-1 and 31.25-1000µg mL-1, respectively. Percent killing was recorded to be more than 90% except for Klebsiella pneumoniae (86.84%). Furthermore, anti-adhesion studies showed that there was 76% hindrance in attachment of E. faecium and 91% in Acinetobacter baumannii at 4xMIC. The highest inhibition in adhesion was found at 4xMIC, which was 46% for A. baumannii and 62% for Enterococcus faecium. Finally, the anti-biofilm capability of the rhamnolipid was determined which ranged between 25%-76% in A. baumannii and 35%-88% in E. faecium. To the best of our knowledge, this is the first study to include research on antimicrobial, anti-adhesive and anti-biofilm activities of rhamnolipid from the local isolate P. aeruginosa UKMP14T against ESKAPE bacteria. Obtained results suggest that this rhamnolipid can be exploited commercially for the production of novel antibiotics.