STUDY OF ANTIADHISION/ANTIBIOFILM EFFECTS OF RHAMNOLIPID-TYPE BIOSURFACTANT AGAINST CLINICAL ISOLATES OF PSEUDOMONAS AERUGINOSA AND ACINETOBACTER BAUMANNII

Background and Aim:P. aeruginosa and A. baumannii are major causes of nosocomial infections due to their highly antibiotic resistance and biofilm formation. In this study, the anti-adhesion and anti-biofilm effects of rhamnolipid against planktonic and biofilm-producing clinical isolates of the P. aeruginosa and A. baumannii were investigated.Methods:26 clinical isolates of P. aeruginosa and A. baumannii were collected from respiratory secretions and burn wounds. The production and purification of rhamnolipid biosurfactant was carried out as described earlier (Hajfarajollah et al. 2015). Rhamnolipid-type biosurfactant was assessed for 1) its ability to inhibit planktonic growth and 2) as an approach to decrease adhesion and disruption of pre-formed P. aeruginosa and A. baumannii biofilms.Results:The MIC of rhamnolipid against planktonic growth of selected isolates of P. aeruginosa and A. baumannii was 1.4 ×107 - 5.9×107 μg/ml and 0.7 ×107 -1.4 ×107 μg/ml, respectively. The effect of the rhamnolipid on the adhesion of P. aeruginosa and A. baumannii cells to polystyrene microtitre-plates was studied. Accordingly, the effectiveness of biosurfactant on different isolates was shown a decrease in cell adhesion varying from 46 to 93%. Biofilms of clinical isolates of P. aeruginosa and A. baumannii were disrupted efficiently by rhamnolipid concentrations between 5.9×107 - 23.6×107 μg /ml and 2.9×107 - 5.9×107 μg /ml, respectively.Conclusion:Our results suggest the possible use of rhamnolipid-type biosurfactant as efficient anti-adhesive and biofilm-disrupting agent in controlling planktonic and biofilm-producing P. aeruginosa and A. baumannii. Further evaluation is required to validate anti-adhesive and anti-biofilm activities observed, at cellular and molecular levels.

کلیدواژه ها:

Pseudomonas aeruginosa ، Acinetobacter baumannii ، Biosurfactant ، rhamnolipid