[Role of "quorum sensing" regulatory system in formation of biofilms by Burkholderia cepacia and Pseudomonas aeruginosa].

AIM

To study influence of chemically synthesized lactones with different length of carbonic chain on formation of biofilms by Burkholderia cepacia and Pseudomonas aeruginosa.

MATERIALS AND METHODS

Fifty-four strains of B. cepacia including reference strains and clinical isolates as well as etalon strain PA103 of P. aeruginosa were used. Lactones C4 [N-(3-hydroxybutanoyl-L-gomoserine lactone], C6 [N-(3-oxoohexanoyl)-L-gomoserine lactone], C8 [N-(3-oxooctanoyl)-L-gomoserine lactone], C0 [L-gomoserine lactone-HBr] were synthesized and purified by column chromatography. Formation of biofilms was studied by determination the ability of B. capacia strains to adhesion on the surface of 96-well polystyrene plate.

RESULTS

Ability to biofilms formation was identified in 83.3% studied strains. It was shown that lactones C4+C8 and C6+C8 when added to cultivation medium improve growth of B. cepacia biofilm. Analysis of optical density (OD) values for P. aeruginosa biofilm revealed that lactones C4, C8, C4+C6, C4+C8, C6+C8 inhibit the formation of biofilm. The most prominent decrease of P. aeruginosa biofilm OD was observed during growth of culture in presence of C0.

CONCLUSION

Obtained data point to different effects of lactones and their combinations on formation of biofilms by B. cepacia and P. aeruginosa. Suppression of biofilm formation by P. aeruginosa induced by lactone C0 confirms the need for development of new bacteriostatic drugs, which will be able to inhibit function of the "quorum sensing" regulatory system.