Synergistic and antibiofilm properties of ocellatin peptides against multidrug-resistant Pseudomonas aeruginosa.

Aim: To test ocellatin peptides (ocellatins-PT2-PT6) for antibacterial and antibiofilm activities and synergy with antibiotics against Pseudomonas aeruginosa.

Materials & Methods: Normal- and checkerboard-broth microdilution methods were used. Biofilm studies included microtiter plate-based assays and microscopic analysis by confocal laser scanning microscopy and atomic force microscopy.

Results: Ocellatins were more active against multidrug-resistant isolates of P. aeruginosa than against susceptible strains. Ocellatin-PT3 showed synergy with ciprofloxacin and ceftazidime against multidrug-resistant isolates and was capable of preventing the proliferation of 48-h mature biofilms at concentrations ranging from 4 to 8× the MIC. Treated biofilms had low viability and were slightly more disaggregated.

Conclusion: Ocellatin-PT3 may be promising as a template for the development of novel antimicrobial peptides against P. aeruginosa. [Formula: see text].