Antibiofilm activity of promethazine, deferiprone, and Manuka honey in an ex vivo wound model.

This study evaluated the antibiofilm activity of promethazine, deferiprone, and Manuka honey against Staphylococcus aureus and Pseudomonas aeruginosa in vitro and ex vivo in a wound model on porcine skin. The minimum inhibitory concentrations (MICs) and the effects of the compounds on biofilms were evaluated. Then, counting colony-forming units (CFUs) and confocal microscopy were performed on biofilms cultivated on porcine skin for evaluation of the compounds. For promethazine, MICs ranging from 97.66 to 781.25 µg/ml and minimum biofilm eradication concentration (MBEC) values ranging from 195.31 to 1562.5 µg/ml were found. In addition to reducing the biomass of both species' biofilms. As for deferiprone, the MICs were 512 and >1024 µg/ml, the MBECs were ≥1024 µg/ml, and it reduced the biomass of biofilms. Manuka honey had MICs of 10%-40%, MBECs of 20 to >40% and reduced the biomass of S. aureus biofilms only. Concerning the analyses in the ex vivo model, the compounds reduced (P < .05) CFU counts for both bacterial species, altering the biofilm architecture. The action of the compounds on biofilms in in vitro and ex vivo tests raises the possibility of using them against biofilm-associated wounds. However, further studies are needed to characterize the mechanisms of action and their effectiveness on biofilms in vivo.

In vitro effect of the iron chelator deferiprone on the antimicrobial susceptibility and biofilms of Burkholderia pseudomallei.

This study evaluated the effect of the iron chelator deferiprone (DFP) on antimicrobial susceptibility and biofilm formation and maintenance by Burkholderia pseudomallei. Planktonic susceptibility to DFP alone and in combination with antibiotics was evaluated by broth microdilution and biofilm metabolic activity was determined with resazurin. DFP minimum inhibitory concentration (MIC) range was 4-64 µg/mL and in combination reduced the MIC for amoxicillin/clavulanate and meropenem. DFP reduced the biomass of biofilms by 21 and 12% at MIC and MIC/2, respectively. As for mature biofilms, DFP reduced the biomass by 47%, 59%, 52% and 30% at 512, 256, 128 and 64 µg/mL, respectively, but did not affect B. pseudomallei biofilm viability nor increased biofilm susceptibility to amoxicillin/clavulanate, meropenem and doxycycline. DFP inhibits planktonic growth and potentiates the effect of ß-lactams against B. pseudomallei in the planktonic state and reduces biofilm formation and the biomass of B. pseudomallei biofilms.