Combinatorial Effect of D-Aminoacids and Tetracycline Against Pseudomonas Aeruginosa Biofilm

Abstract

Objective: The present study attempted to evaluate the anti-biofilm activity of D-amino acids (D-AAs) on Pseudomonas aeruginosa and determine if the combination of D-AAs with tetracycline enhances the anti-biofilm activity in vitro and ex vivo. Methods:Different D-AAs were tested for antibiofilm activity against wild type P. aeruginosa PAO1 and two multidrug resistant P. aeruginosa clinical strains in the presence of sub inhibitory concentrations of tetracycline using crystal violet microtitre plate assay. Results were further validated using in vitro wound dressing and ex vivo porcine skin models followed by cytotoxicity and hemocompatibility studies.Results: D-tryptophan (5 mmol) showed 61 % reduction in biofilm formation of P. aeruginosa. Interestingly combinatorial effect of 5 mmol Dtryptophan and 0.5 minimum inhibitory concentration (MIC) (7.5µg/ml) tetracycline showed 90% reduction in biofilm formation. 5 mmol Dmethionine shows 28 % reduction and combination with tetracycline shows 41% reduction in biofilm formation of P. aeruginosa. D-leucine and Dtyrosine alone or in combination with tetracycline did not show significant anti-biofilm activity. D tryptophan-tetracycline combination could reduce 80 % and 77 % reduction in biofilm formation in two multi drug resistant P. aeruginosa clinical strains. D-tryptophan-tetracyclinecombination could also reduce 76% and 66% reduction in biofilm formation in wound dressing model and porcine skin explant respectively. The cytotoxicity and hemocompatibility studies did not show significant toxicity when this combination was used. Conclusion:The results established the potential therapeutic application of D-tryptophan alone or in combination with tetracycline for treating biofilm associated clinical problems caused by P. aeruginosa.

Potent synergistic combination of rosuvastatin and levofloxacin against Staphylococcus aureus : in vitro and in vivo study

“…The calculation of percentage inhibition of biofilm formation was done using the following formula: Percentage (%) reduction of biofilm = (optical density of control − optical density of test)/optical density of control) × 100 (Jayalekshmi et al . 2016). The concentrations, which caused a synergistic effect against S. aureus biofilm, were used in microscope analysis of biofilm.…”

D‐tryptophan, an eco‐friendly natural, safe, and healthy compound with antimicrobial activity against food‐borne pathogens: A systematic review

“…Moreover, in the food industry, biofilms cause microbiologically influenced corrosion (MIC), equipment failure, economic losses, and environmental damage (Elgamoudi et al., 2020 ; Jia, Li, et al., 2017 ; Jia, Yang, et al., 2017 ; Wu et al., 2015 ). Studies have shown that D‐tryptophan alone or in combination with a mixture of other D‐amino acids can have antibiofilm properties (Brandenburg et al., 2013 ; Elgamoudi et al., 2020 ; Ghosh et al., 2019 ; Jayalekshmi et al., 2016 ; Jia, Li, et al., 2017 ; Jia, Yang, et al., 2017 ; Kolodkin‐Gal et al., 2010 ; Leiman et al., 2013 ; Li et al., 2015 ; Zilm et al., 2017 ).…”